The Awesome Science of Coffee Production

By Sydney Hubbard

During the summer of 2017, Kayla Bellman was working with Habitat for Humanity delivering latrines, smokeless stoves, and water filters to families living in extreme poverty in a remote region of Guatemala. This particular region, along with many other rural, agrarian areas of Guatemala, had a local economy largely pillared on coffee production. It was during this summer that her team hired a mason, Luis. To make ends meet, Luis worked for Habitat for Humanity and on a nearby coffee farm as a picker. Kayla soon realized that, despite having two jobs, Luis and his family were still living well below the poverty line.

How could such a large, profitable industry, like the coffee industry, leave its laborers and producers so vulnerable?

Workers at a milling and processing station in El Salvador hand-sorting green coffee for defects.

Workers at a milling and processing station in El Salvador

As Kayla continued her work with Habitat that summer, she noticed a pattern: “Most of the families that qualified for Habitat assistance had one or more family members employed as manual labor on local coffee farms. These people had full-time, legitimate employment, and yet they were still living on one dollar a day.” How could such a large, profitable industry, like the coffee industry, leave its laborers and producers so vulnerable? The dots Kayla connected that summer pointed her towards glaring gaps and severe inequities in the coffee value chain and set her on a path not only towards a more mindful consumption of that product but ultimately to a career in development.

It is a little too late in the day for coffee, so I sit with Kayla Bellman and her colleague Aelish Brown over craft beers at the Bookhouse Pub in Atlanta to discuss the fundamentals of coffee production, the coffee value chain and finance sector, and fair trade, among other topics. Kayla is a current student in the Masters in Development Practice program at Emory University and a project intern at Transparent Trade Coffee (TTC), a program at Emory University’s Social Enterprise at Goizueta Center (SEG). Aelish Brown is a program associate at SEG.

As I am a coffee novice in all senses of the word, I ask them to start at the beginning: How does coffee travel from a distant farm in a foreign country into the filter used for my morning drip? Aelish patiently explains this process, known as “bean to cup.”

Where does coffee come from?

Green coffee cherries

Green coffee cherries growing in Guatemala pre-harvest season.

Coffee is grown on trees (genus Coffea) with beautiful white flowers in tropical climates, typically in Latin American, Asian, or African countries. These white flowers produce cherry-like fruits that change color from green to red and are harvested once a year over an approximately three-month period. Inside the skin of these red cherries are several hard seeds, which will become coffee beans. Farms hire local, seasonal labor to handpick the red cherries to procure the seeds inside. If the farm is in an area with access to adequate supplies of water, the seeds undergo a “wet process” in which they are fermented in tanks of water for 24 hours to remove the excess pulp from the fruit and then dried.

Drying patio where honey-processed coffee has been laid out in the sun.

Drying patio at a milling and processing station near Ataco, El Salvador

However, if water is scarce, farms opt for a “dry process” in which seeds are placed on giant patties to dry in the sun, and then the excess fruit is removed. Once the seeds undergo one of these processes, the resulting beans, often referred to as “green coffee,” are sorted by size, graded for quality, and bagged for sale. Individual farms or cooperatives (groups of farms investing in equipment and labor together) then sell these bags to an exporter. Exporters are based out of producing countries. They typically coordinate with importers in consuming countries in the global north (United States, Europe, etc.) to move the green coffee via cargo ships. Importers and exporters coordinate putting this haul in warehouses and listing the types of coffee.

The actual roasting of green coffee takes place in importing countries. The beans are placed in roasting machines and transform into the brown beans we know, love, and purchase in stores.  At this point, a roaster will go to the warehouse, select and buy coffee, and move it to stores and coffee shops where it is ready for consumption. (For a video of the process, here’s NPR’s Bean to Cup.)

The fundamentals of coffee production

The coffee ecosystem includes the labor of farmers and their employees, as well as importers, exporters, roasters, and consumers.  Also swirling around this delicate ecosystem is the finance sector and something called the C price. “Coffee is treated as a commodity by the New York Stock exchange. The trading price of a green pound of coffee is known as the ‘C price,’ and this figure ultimately affects the price of coffee,” Aelish describes. Like other commodities, the law of supply and demand determines the C price. For example, if there is coffee scarcity, the price will go up until consumers stop buying it because it is too high. If there is an abundance of coffee, the price will drop.

The average production cost of coffee ranges anywhere from $1.05 to $1.40 per pound.

Green coffee warehouse in El Salvador, where labelled lots await the final round of milling and sorting before they are ready for export and roasting

Labeled lots await the final round of milling and sorting before they are ready for export and roasting

The C price should reflect how much coffee is available and how much people want it. However, this is not exactly how the C price operates in reality. Much of the pricing around coffee is determined via speculation of what the price of coffee will be on a future delivery date. If there is speculation that the price of coffee will drop in the future (say due to abundance), people will start selling coffee and futures contracts, and the CURRENT price of coffee will drop. Therefore, the C price is not linked to current, real market conditions but to highly variable market predictions, and this can have a severe impact on the price of coffee and coffee producers.

According to Caravela, the average production cost of coffee ranges anywhere from $1.05 to $1.40 per pound. With recent booms in coffee production, the C price has dipped as low as one dollar per pound, leaving coffee farmers in the red. Furthermore, considering that the majority of cost around coffee production is labor, farmworkers like Luis often withstand the worst of this deficit.  And it is in this way that the cycle of poverty remains at the farm level, and profits stay in the hands of large companies.

Third-party certifications of coffee products were born to attempt to fix this problem and to assure consumers the product was harvested under both eco-friendly and economically fair conditions; the most well known of these certifications is “fair trade.” Fair trade guarantees a minimum price for commodities (like coffee) to ensure that laborers in producing countries are paid a just wage. When the C price falls, they are still paid the agreed-upon minimum price for their product. In theory, this minimum price creates a safety net for farmers.

However, if the C price happens to take an upswing, under fair trade rules, coffee growers are paid the same fair-trade price (even if the C price exceeds this price). Or as Aelish put it, “When you create a floor, people will sit on it.” Basically, fair trade ensures that farmers do not lose when coffee prices fall, but they do not gain when the prices climb either. In this scenario, again, the benefits and profits often fall into the hands of large companies. 

Direct-trade coffee alternatives

Many experts in the coffee industry argue that a blanket minimum price is not the solution. Instead, prices need to be based on the real cost of production, which varies by country, and emphasis needs to be placed on transparency along the entire value chain. This is where new buying models and social enterprises like TTC enter the picture.

TTC is one of a number of organizations spearheading a direct-trade approach to the coffee industry. Essentially, direct-trade approaches cut out the middlemen. Small coffee farmers sell directly to buyers and are often paid substantially more in the process. TTC has compiled a list of “Transparently Traded Coffees” that allows consumers to see the effective return to origin, or the percentage of a coffee retail sale that goes back to farm, for each brand of coffee. This information allows consumers to know exactly how much a farmer was paid for his/her product and make their own informed choices about which coffees to buy (Transparent Trade Coffees).

In the end, the ultimate goal of third-party certifications and direct-trade approaches is to get money out of the hands of big corporations and back into the hands of small farm owners and their laborers, allowing people like Luis to provide for their families and lift themselves out of poverty.

Think before you drink

As we finished our beers and our conversation, Aelish Brown made her final call to action: “We all have that one thing we care about: maybe it’s coffee, maybe it’s clothing, maybe it’s this craft beer we’re drinking. Whatever it is, I hope that learning about the value chain of coffee and thinking about where it comes from has incentivized you to care OR at least think more critically about other products. Even if I haven’t reframed the way you think specifically about coffee, even if you don’t practice it day-to-day, I hope you can take this logic and thoughtfulness and apply it to that one thing you care about.”

Thank you to Kayla Bellman and Aelish Brown for teaching us about the incredible science of coffee production! Check out Transparent Trade Coffee for direct-trade coffee that helps support small farmers.

For more Awesome Science of Everyday Life features and other science updates, follow Science ATL on FacebookTwitter, and Instagram!

The Awesome Science of Music Technology


Close-up photo of a hand adjusting dials on a music mixer in the music technology field.

Photo by Drew Patrick Miller on Unsplash

By Amin Ghane

Musicians spend countless hours tweaking, calibrating, and arranging sounds and ideas to create your favorite jams. And then, of course, there are the instruments themselves that provide a conduit through which creativity can be expressed. The field of music technology develops and improves how musicians create – and how we interact with – music.

17th-century music technology

Dating from 1720, this grand piano was invented by Bartolomeo Cristofori.

Breakthroughs in music technology have always led to booms in musical innovation. Consider that most ubiquitous of all Western instruments: the piano. Invented around the 18th century by Bartolomeo Cristofori, the piano was an advancement upon the harpsichord, which introduced the musician’s ability to adjust the volume and duration of the notes played. Classical and Romantic musicians took advantage of these attributes to create some of the most enduring pieces of all time. 

And the work of music technologists hasn’t stopped. In fact, advances in computation have provided musicians the power to produce, edit, and play their music with more flexibility and expression than ever before. Whereas the work of recording and editing music was previously reserved for experts who would charge a fortune for their services, now anyone with an iPad and some curiosity can get into the basics. The latest, top-of-the-line synthesizers are producing noises that grip our attention.

From the underground artist slapping together beats in their garage to the latest number one hit from Taylor Swift, music lovers of all styles benefit from this innovation. To take a look at what’s going on the front lines at the intersection of technology and artistic expression, I ventured to Georgia Tech’s School of Music, which houses one of the country’s foremost academic and research programs in music technology.

The future of music

Innovation on display at Georgia Tech’s annual Guthman Musical Instrument Competition

As I walked into the J. Allen Couch Building, I was immediately greeted by the sound of violins filling the sonic space between gentle scales being played on the cello. These musical instruments are centuries old, but I’m here for what is emerging from the cutting-edge music labs on the second floor. As he leads me upstairs, Avneesh Sarwate, a master’s student in music technology, explains, “Most of those kids also spend a lot of time building synthesizers and coding. Half of them are also in the laptop orchestra.” In a discipline as ancient as music, it is eye-opening to see first hand how intimately the old and new are joined in this hub of experimental music.

In a discipline as ancient as music, it is eye-opening to see first hand how intimately the old and new are joined in this hub of experimental music.

We walk down a long hallway, passing rooms and labs that each have their own character. One room has gigantic speakers surrounding a sole computer monitor, while the next has what looks to be an entirely newly invented instrument made out of scrap metal sitting amid piles of tools and screwdrivers. Avneesh notices my confusion. “Oh yeah, that lab is working with acoustical engineers. I don’t think it’s ready yet.” I intuit that acoustical engineers, who study the control of sound or noise, must play a central role in the development and design of any instrument because they study how different materials and design elements will determine how the sound, well, sounds.

Finally, we arrive at his lab at the end of the hall on the left. As Avneesh swipes his ID card and the door swings open, I’m greeted by what looks, at first, like a traditional computer lab. On second glance, I see some clues about what goes on in here: stacks of keyboards and mixing boards around the room, for example, or the piles of sheet music strewn about on the desks.

“I was a very creative kid growing up. I played guitar and my dad did whatever he could to help me grow creatively,” Avneesh tells me as his computer boots up. “I went to school for software engineering, but I never really stopped playing music. At some point, I just figured I’d use software to help my music and that’s how I got into interactive art.” 

“At some point, I just figured I’d use software to help my music and that’s how I got into interactive art.”

When I ask what he means by interactive art, Avneesh opens a program on his computer and starts typing computer code. Just when I feel I can’t take the anticipation any longer, the speakers on either side of his desk come alive with an ethereal melody looping around a drumbeat that, while simple, demands my attention. “This is a module I wrote that lets you generate melodies with algorithms.” Then, with another line of code, the melody shifts: whereas before the synthesizer was coming out of each speaker equally, the melody now faded between the speakers, almost oscillating, creating a rather gripping effect. I was reminded of the way thoughts swirl together when one is on the cusp of sleep.

Bringing art to life with technology

Live coding in action

What Avneesh is doing is called live coding, creating art in real-time using computer code – whereas software is traditionally written, tested, debugged, and then used, live coding allows one to use programming as an actual instrument, the way you would a keyboard or a guitar. And it doesn’t stop at music.

“Yeah, I’ve actually done this with performance art as well.” He’s referring to Paradise Lost, an “immersive musical theater performance for which I developed interactive graphics.” He shows me videos of performers dancing while he live-coded various graphical effects onto the performance. In one, the dancers are given a wave-like effect while in another, mesmerizing pixelation effect reminds one of a faded memory. Bravely, Avneesh displays the code on the screen the whole time for the audience to see. “That would’ve been a bad time for a typo!” he says with a smile.

Avneesh is especially interested in developing interfaces, ways to foster connection between live-coding musicians and musicians who are playing physical instruments live. In one paper, he prototypes tools that allow traditional performers to see and understand what the coder is doing. One method uses colorful balls to represent notes, which move around in a pattern that corresponds with the code. “A big part of my work is making everything as accessible as possible,” he says. And it’s true – Avneesh has also been part of an effort to create an entirely new platform for creating computer music aimed at non-technologically inclined musicians, thereby opening new doors for creativity.

“A big part of my work is making everything as accessible as possible.”

I peer into another room on our way out, expecting some more engineering and computer equipment. Instead, there sits a lone baby grand piano in the corner facing a few rows of chairs. I smirk, thinking of where we’d be if the harpsichord had never been improved on. Thanks to the work of people like Mr. Cristofori in the 1700s – and Avneesh today – the bounds of music will never stop expanding.

Thank you to the Georgia Tech School of Music and Avneesh Sarwate for sharing their interactive music technology! Follow Science ATL on FacebookTwitter, and Instagram for more Awesome Science of Everyday Life features and other science updates.

The Awesome Science of Traffic

Traffic jam in Atlanta, Georgia.

By Ana Cheng

Atlanta is the 11th most congested city in the country, and most ATLiens are familiar with the frustrating ballet of rush hour traffic. On average, drivers lose 97 hours and $1,348 each year just stuck in traffic. Atlanta is also the fourth fastest-growing city in the country, meaning our roads will have to support increasingly more commuters year over year. However, like with most modern-day problems, there are teams of scientists and engineers heroically searching for ways to improve our lives. I spoke with Dr. Jorge Laval, a civil engineering professor at Georgia Tech who specializes in transportation, to find out more.

What is Traffic Theory?

The field of traffic theory can trace its roots back to the mid-twentieth century, shortly after cars gained popularity. Engineers began measuring traffic flow with cameras and appropriated fluid mechanical concepts to describe the patterns they observed, likening traffic to the flow of water in rivers. Since then, new models and technology have enabled research through advanced simulations of driver behavior. Dr. Laval, who has been studying transportation for twenty years, uses this technology to study traffic patterns. He’s among a handful of transportation researchers at Georgia Tech and part of the Georgia Transportation Institute, a consortium of researchers at various universities working in policy and planning, environmental issues, transportation technology and infrastructure, and traffic operations.

Driving simulator at Georgia Tech.

The Autonomous and Connected Transportation Driving Simulator Laboratory (ACT-DSL), a driving simulator in the lab of Dr. Srinivas Peeta (Georgia Tech) which helps researchers better understand human driving behavior.

Although these researchers use sophisticated simulations and math to understand traffic patterns, one does not need a PhD in civil engineering to understand the real-world effects of congestion. “You’re a driver, so you experience it every day,” says Dr. Laval. Take, for instance, the concept of capacity drop. Capacity refers to the maximum number of vehicles that may pass a given point on a road during a given period of time. Because of varying road conditions like accidents or lane changes, this number might drop, causing a disproportionate effect on traffic. “When [capacity] drops, it goes down by typically 10-20%. It doesn’t sound like much, but in queueing systems like these, that’s a huge difference. It could mean twice the delay,” explains Dr. Laval. 

To understand factors that contribute to changes in capacity on a macroscopic scale, he and other theorists utilize fundamental diagrams, created using data collected by loop detectors (those pairs of black cables laid across the road). Every city or “network” of roads has a unique set of properties that give it a characteristic fundamental diagram, meaning that the diagrams for Atlanta and Los Angeles will be different. Once researchers have obtained a diagram for a specific network, all they need to know to understand current road conditions is the number of vehicles on the road, which they can count with loop detectors (those pairs of black cables sometimes laid across a road). From this, they can glean the average speed and travel time for any given path. For example, researchers can look at the diagram below and find the optimum density of cars for maximum flow or the least traffic (labeled with a red star).

Fundamental diagram of traffic flow

What Causes Traffic?

In order to apply what they know, researchers must first understand what causes traffic in the first place. Freeway on-ramps, accidents, and rubbernecking are obvious culprits. The unifying factor in all traffic jams is human error. Consider the on-ramp scenario: when vehicles enter the freeway, they’re typically going slower than the rest of traffic, creating small disturbances in flow. It’s made worse when other cars start to change lanes, causing disruptions across multiple lanes. In fact, lane-changing activity is the main contributor to capacity drop. In other situations, traffic jams seemingly appear out of nowhere. In these cases, slight variations from driver to driver lead to minute braking and acceleration, which become magnified as following cars react. Dr. Laval calls these stop-and-go waves. 

In downtown areas, traffic is mainly influenced by the length of city blocks and the timing of green lights (called green time). Short blocks mean a lot of stopping and starting, which is a recipe for traffic disaster. If the lights aren’t synchronized efficiently, spillback can happen. Spillback is the phenomenon that occurs when cars move forward because their light turned green, but end up blocking intersections because the next light is still red. The ideal grid has long blocks and short green lights, minimizing the spillback effect. However, if we zoom out on dense urban areas, not even traffic light coordination has much of an effect on the average speed of the network. The main factors remain the block length and average green time.

As for why Atlanta traffic is especially bad; it’s surprisingly not due to our non-grid layout. Dr. Laval blames sprawl and underuse of public transport for increasing the number of vehicles on the road. Moreover, our infrastructure was built using outdated traffic models—and for a much smaller population than that of present-day Atlanta.

Fortunately, Dr. Laval is working on ways to bring our roadways into the twenty-first century. He’s developed a variable speed limit algorithm which adjusts the maximum speed on the freeway to optimize the capacity. “It hasn’t worked really well because people don’t comply,” he laments. It’s because the algorithm can sometimes seem counterintuitive: drivers who read a speed limit of 45 mph tend to drive faster if they don’t see many cars on the freeway, even though the displayed limit will improve the capacity. So now Dr. Laval is hoping to coordinate variable speed limits with real-time ramp metering algorithms—algorithms that respond to current traffic conditions by adjusting the rate of green lights—in a collaboration with the Georgia Department of Transportation (GDOT).

Reducing Traffic Congestion

Diagram of Atlanta's roads, courtesty of Dr. Laval.

Diagram of Atlanta’s roads, courtesy of Dr. Laval.

The unfortunate truth is that to minimize overall traffic, some people would have to take longer routes. It might seem straightforward for every driver to take the most direct route to their destination, but this has a hidden social cost—increased traffic due to congestion on popular roads. Introducing congestion pricing might help accomplish that by making it less enticing to take a busy road if it comes with a pricier toll, even though it may be the shortest route. With this system, “People act as if they’re minimizing their own cost, but they internalize their social cost. That’s one way in theory that you can have people choose their own routes but have tolls such that the equilibrium is going to give you the system optimum,” explains Dr. Laval.

In other words, by making the more socially costly (read: busier) roads more financially costly with tolls, enough drivers will take the cheaper routes that it will minimize the overall traffic. However, it may mean that only wealthier drivers have an improved driving experience. Alternatively, apps like Waze and Google Maps also have the power to offer drivers alternate routes that would improve overall traffic without the economic barrier posed by congestion pricing. Being able to regulate the behavior of every car through an app? “That’s the holy grail of city planning,” says Dr. Laval.

Another simple fix is encouraging more people to utilize public transit options. Studies have found that if 1% of drivers opted for public transit, average commute times could be reduced by 18%. Further, because less congestion would lead to more reliable bus schedules, it would start a virtuous cycle that would make public transit even more appealing and reduce traffic in addition to its environmental and health impacts.

“We know nothing about (autonomous vehicles) and that’s a problem because they’re coming—they’re already here.”

Overall, in order to truly eradicate congestion, we must remove human error from the driving equation. Could autonomous vehicles (AVs) be the grand solution? Dr. Laval explains there’s a shift happening in the field of traffic research as AVs have begun to hit the road. “We know nothing about AVs and that’s a problem because they’re coming—they’re already here,” he says, “We don’t know what they are going to do to capacity. My bet is that it’s going to be bad in the beginning. Due to safety concerns, they will overreact and be very conservative by driving really slowly.” In fact, the current models show that when mixed in with human drivers AVs are worse for traffic, likely due to programming that overcompensates for safety concerns. We may not see the benefits of AVs until they make up the majority of the road. So until their inevitable takeover, take the bus when possible, obey variable speed limits, and don’t change lanes near bottlenecks.

Thank you to Dr. Jorge Laval for navigating through the science of traffic patterns in Atlanta! Follow Science ATL on FacebookTwitter, and Instagram for more Awesome Science of Everyday Life features and other science updates.

Cracking the Science Behind Pottery with MudFire Pottery Studio

By Helen Siaw

MudFire Studio in Decatur, GA

MudFire Studio in Decatur, GA

Two rows of pottery wheels sit at the center of the pristinely clean 8000 square-feet studio, surrounded by shelves of artwork done by the studio’s members, Mudfire Pottery Studio is a go-to pottery studio for the local community. Daphne Ranlett and her partner Deanna Ranlett have been running the studio since 2013. Daphne’s passion for pottery stemmed from a ceramics course in college. “The science behind pottery and the process in crafting it are intriguing.” With a Bachelor of Fine Arts in ceramics from Georgia State University and decades of experience, Daphne is a tried-and-true expert in ceramics.

Clay, water, fire – essential elements in pottery making go back thousands of years. The oldest known ceramic artifact was a figurine constructed about 32,000 years ago in the early Stone Age. In the Bronze Age, the invention of glazes and pottery wheels opened a realm of new possibilities for artists to shape and decorate. Today, local studios like MudFire Pottery Studio provide the community a place to create and innovate these ancient elements.

It All Begins With Clay

Clay contains a mixture of minerals, which determine the temperature needed to transform soft clay into hard ceramics (firing temperature). Kaolinite is one of the major clay minerals. In kaolinite, two minerals are linked together by oxygen atoms to form a sheet-like structure. Similar to how buttercream frosting holds a two-tiered cake upright, molecular interactions between the mineral sheets help to maintain the shape of the clay. When force is applied to the clay these interactions allow the mineral sheets in the clay to slide past each other. This unique property allows it to be shaped and formed by the potter.1

Meredith Bradley, one of the studio’s resident artists, showed us how to shape wet clay on a pottery wheel.

Meredith Bradley, one of the studio’s resident artists, showed us how to shape wet clay on a pottery wheel.


The wet clay can be shaped using a hand building method or with wheel throwing. With hand building, potters frequently use simple tools to create a piece. Wheel throwing utilizes a pottery wheel. This method depends on a balance between the force exerted on the clay when the pottery wheel spins and the friction between the clay and a potter’s hand. “Wheel throwing is all about the rhythm,” Deanna says with a smile. 

Once a piece is molded into the desired shape, the pottery is left to dry before firing. “You have to let water evaporate from the clay as much as possible before firing. Otherwise, any water trapped in the clay body will turn into steam at 100oC, and it will burst the clay piece,” Daphne warns. 

The air-dried pot is then heated to drive off any lingering water. This heating process transforms the sliding mineral sheets into a stronger network of crosslinked clay particles. From this stage, the clay cannot be reshaped by adding water. Now, layers of ceramic glaze can be applied to this piece, for either decorative or practical purposes such as holding foods.2 

Artists’ Experiment

MudFire studio has a kiln room for members to fire their artworks. They also have an impressive collection of glazes.

MudFire studio offers an impressive collection of glazes.

Ceramic glaze consists of metal oxides, which give colors to glazes because of their light-absorbing properties.2 As a result of this light absorption property, we see the complementary color. For example, when orange light is absorbed by a metal oxide, we see the blue color. “Cobalt gives a blue color, iron gives a brown color, manganese gives a pink color,” Daphne explains as she shows us the mini ‘laboratory’ they have for preparing glazes.

“We like to experiment and mix our own glazes. We melt each glaze ingredient at a different temperature and observe what will happen. Then we mix different ingredients at different concentrations to see if we can get a different effect.” Through this trial-and-error process, artists at Mudfire Studio created 22 new glazes from scratch.

Bracing the Heat!

Pottery produced by resident artists are available for sale at the studio.

Pottery produced by resident artists are available for sale at the studio.

At the back of the studio is where all the firing happens – in a furnace called a kiln. MudFire carries three different types of kilns: electric, soda, and raku. “An electric kiln is basically an oven with a built-in temperature sensor. There’s not much interaction,” Daphne says. Firing with an electric kiln is similar to baking cookies in an oven. The potter has no control over firing conditions besides the temperature and firing time.

With soda firing, a drop of soda ash solution is added to the large gas furnace at peak temperature it vaporizes immediately and attracts the soda ash to particles in the clay and to the glaze, giving unique patterns. “It’s magical! You have no ability to control where the soda deposits or the final firing pattern. It’s submitting to the will of the firing elements,” says Daphne.

Raku firing, the last method offered at the studio, operates very differently from other firing techniques. The clay piece is first quickly heated up to 1800 oC in the furnace, then immediately placed in a bin with combustible materials such as newspapers, causing simple chemistry to take place. The newspaper reacts with oxygen in the air and generates carbon. The carbon then reacts with the oxygen in glaze’s metal oxides and strips it away, a process known as reduction.3 Raku firing tends to produce thin and fragile pottery with easily chipped glaze surface due to its rapid-firing process.4 “Raku is not food and beverage safe. It’s just decorative,” Daphne says as she walks us through the warm kiln room. 

Where Clay Meets Community

MudFire studio resident artists, Kaitlyn Chipps, Meredith Bradley, Marisa Mahathey, and owner Daphne Ranlett (middle).

MudFire studio resident artists, Kaitlyn Chipps, Meredith Bradley, Marisa Mahathey, and owner Daphne Ranlett (middle).

Whether you are a pottery expert or a beginner, Mudfire Studio opens their door to everyone. “We aim to create a safe space for expression,” she explains, “Leave your baggage at the door. Come on in and create.” Besides ceramics, Daphne and Deanna value mentorship to young ceramic artists. They work closely with other young pottery business owners and are in the process of setting up professional development workshops. For more information about Mudfire Studio, you can find them on Facebook, Instagram, and Twitter, or visit

“What’s the next step for MudFire after this?” I ask.

“Global domination,” says Daphne.

Thank you so much to Daphne Ranlett and the artists at Mudfire Pottery Studio for taking us through the science of behind pottery! Follow Science ATL on FacebookTwitter, and Instagram for more Awesome Science of Everyday Life features and other science updates.

1 Breuer, S. The Chemistry of Pottery. Education in Chemistry, July 2012, pp 17-20.
2 Bloomfield, L. Techno File: The Chemistry of Color. Ceramics Arts Network Daily,
3 Whitaker, G. Using the Raku Glazing Process to Show Oxidation-Reducation in Chemistry. U.S. Department of Energy, Pacific Northwest Laboratory, pp 6.51-6.59.
4 Branfmann, S. Successful Tips and Techniques for Raku Firing. Ceramics Arts Network Daily,

The Awesome Science of Apples at Mercier Orchards

By Laura Mast

Apple orchard at Mercier Orchards.

“There’s a lot more science than people realize. People think, you go out there, you dig a hole, you plant a tree and pick it. There’s a lot more.” David Lillard, orchard manager at Mercier Orchards, leans back in his chair and smiles good-naturedly at me and Ian Flom, Mercier’s brewmaster. Flom adds, “I grew up local, in this area. I knew Mercier’s was an apple farm, but I didn’t realize how extensive the process was until I actually became an employee here.”

“There’s a lot more science than people realize. People think, you go out there, you dig a hole, you plant a tree and pick it.”

In its 75 years of operation, Mercier Orchards has grown to over 300 acres with over 100 thousand fruit trees. Nestled in the North Georgia Mountains, it’s blessed by temperate conditions perfect for growing apples: moderate summers, cold winters, and high humidity. Lillard tells me they get 60” of rain every year. 

These features, though, also present dangers. Moisture is also great for pests, and an early frost in the spring could kill the budding fruit. Keeping these many trees – and the new trees they buy each season- healthy and hearty, takes a careful eye, hard work, and of course: science. 

A flood of pheromones, and a blanket made of ice

Lillard has a few tricks up his sleeve to handle pests and frost. 

“There’s just no way I can fight that disease cycle organically in this neck of the woods,” says Lillard. But instead of using pesticides every year, they rotate in four-year cycles. They’ll do a round of regular pesticides in one year, and then for the other three, they do an organic treatment focusing on the two most prevalent pests: the oriental fruit moth and the coddling moth. 

Each spring, orchard laborers go into the fields and hang lures from the branches of every other tree. These lures, which look like bread ties, are soaked in insect pheromones, and flood the orchard with scent for the next 90 days. These confuse the male insects, who use the smell to track female insects. As a result, the males are unable to locate and breed with female insects. 

If insects are a long-term issue, weather is a short term one. “I spent a lot of time, effort and money getting a crop to a certain point and I could lose everything in five seconds if Mother Nature decides to take from us. You have to be pretty zen to work in this industry,” says Lillard.

“You have to be pretty zen to work in this industry.”

If the temperatures are forecasted to drop so much that the apple buds are in danger, Lillard turns on an overhead irrigation system. This system mists water vapor over all the trees. As the water condenses on the trees, it goes from a gas to a liquid. This is an exothermic reaction, meaning the water releases heat onto the buds, keeping them warm. 

Keeping trees healthy is important because if “a tree gets sick,” says Lillard, “that’s it. There’s no cure- only prevention.” 

One particular strategy for keeping trees healthy is, unsurprisingly, starting out with healthy trees.

Where do baby trees come from?

Close up on gardener man hand grafting apple tree

Well, in the case of apple trees, it’s not quite what you think. Apple trees are not “true to seed:” that is, if you were to take the seeds from your Red Delicious apple at lunch and plant them, and grow them into a tree, the fruit from that tree would not produce Red Delicious apples. “They might taste like cork, but it will be an apple,” laughs Lillard. 

Ninety-nine percent of all apple trees in the US are produced using a technique called grafting. A grafted apple tree consists of two parts: the rootstock, which includes the roots and the base of what will be the trunk of the tree, and the scion, which is the stem. A wedge is cut out of the rootstock, and the base of the scion is cut into a wedge. The two ends are jig-sawed together and wrapped until they heal together. You can see this junction in a young tree as a distinct bulge in the trunk a few inches above the ground.

While it’s easy to see the role of the scion- it creates the apple varietal you want! – the role of the rootstock is a little more complex. The rootstock controls the size of the tree, the age when the scion will start to produce fruit, how the tree responds to adverse conditions like weather, insects, and diseases, and more. 

Most orchards, including Mercier, order their trees from nurseries. It takes three to four years to grow the rootstock, and then several more years before the tree is ready to bear fruit. 

Predicting the future

Close up shot of a bag of apples from Mercier Orchards.

Image credit: Select Georgia

“I’m 5, 6, 7 years down the road before a tree is going to produce so I got to make sure I get what you want in seven years,” says Lillard. To choose new apple varieties, he and his team will go to horticulture shows and taste test: “We sit down and we’ll sample 100 apples, and we’ll figure out what they taste like. We learn how it’s been growing in the nursery, some other characteristics and then we’ll say hey, that’s a good one. We’ll plant that one and we’ll try that one.”

“I’m 5, 6, 7 years down the road before a tree is going to produce so I got to make sure I get what you want in seven years.”

After working in the orchard for twenty years, Lillard knows his trees: where you could get out fancy scientific gadgets to measure color and sugar, he just uses his hard-earned experience.

“There’s not a lot to it,” says Lillard. “If I know it’s that time of year, so if I know that reds come in at the beginning of September, I’m looking at Red. Do they have enough color? Are the seeds black? Do they taste good?”

You can always try taste-testing yourself: Mercier Orchards offers U-Pick weekends through the summer through the fall, during prime harvest seasons, complete with tractor rides throughout the farm. Put it in your calendar! “If I like them, and they’re ready to go, well, that means you’re gonna like them.”

Can one bad apple really spoil the bunch?

Assortment of apples from Mercier's Orchard

Assortment of apples from Mercier Orchards

Turns out, yes, and here’s where the cool science comes in with harvesting: storing the apples. You may have noticed that just about any time of year, you can buy apples, as if they were just freshly picked yesterday. This is the result of treatment with 1-methylcyclopropene, or 1-MCP.

As fruits ripen, they release a natural plant hormone called ethylene. This gas prompts the plant to ripen even further: the fruit becomes softer and sweeter, until your forgotten apples are mealy and soft. The ethylene binds to ethylene-specific receptors in the apple skin, which fit together just like a jigsaw puzzle. 

1-MCP looks very similar to ethylene, and it can trick the receptors into letting it bind in ethylene’s spot. 1-MCP treatment fills all the receptors for ethylene with 1-MCP instead, effectively hitting pause on ripening. 

This allows growers to ship out fresh fruit all year round, so you can make your own apple pie any time of year (or, pick up your own or order from their store any time!). 

Come for the apples, stay for the (hard) cider

Display of apple ciders and beverages at Mercier Orchards.

The Tasting Room at Mercier Orchards

At Mercier Orchards, the  apples are divided: of course, there’s fruit for sale in the marketplace, and a good portion goes to the kitchen for pies, fried pies (you haven’t lived until you’ve had one, they sell over one million annually), breads, jams, preserves, relishes, butters and all kinds of sauces, and more. But the rest goes to cider, both hard and regular. This is Ian Flom’s territory. As the brewmaster, he’s led the production of hard cider in particular; regular cider has been an orchard staple for decades.

“When I started making cider, it was just a way to get rid of fruit that I couldn’t sell in the market. Now, I set aside blocks of trees purposely as cider fruit,” says Lillard. This has allowed Flom and his team to experiment with a lot of different flavors. Flom says the most variability in regular and hard cider flavors come from the apples: with 10,000 varieties of apples, it’s easy to see how. 

The main things to consider are sugar content and acidity, says Flom. “You’re not going to have the same acidity level in a Red Delicious versus a Mutzu or a Granny Smith, right? Well, just that difference in the acidity can change your flavor profile of your juice. If you were to heavy on the reds and get, let’s say, one part green apple, and then you’re not gonna have the same tartness after fermentation.”

Fermentation is done very similarly to wine: yeast is added to the apple juice mixture, and it consumes sugars, producing alcohol. Fermentation only takes about two weeks; in fact, for a 500 gallon batch of hard cider, going from apples to bottle takes only 18 days. But it’s after fermentation that the fun begins.

Experimenting with Flavor

Flom tends to experiment with small batches (3.5 gallons) at home before bringing his ideas to work. He says the open-minded and passionate attitude of the team has led to some fun discoveries. 

The Just Peachy recipe, a hard sweet peach cider, transformed along this vein. “I remember, David asked me ‘why don’t we do something hot?’ Why not? And then you know, through some trial and error, we end up with the Jalapeacho, which is one of our top sellers.” 

Another example is the Gone With The Ginger, a sweet hard cider that was born after Flom had been cooking at home. “What if I put some ginger in it? What if I cut it up first, what if I roast it, cook it? So it’s a little trial and error.”

Regular cider doesn’t require nearly as many steps. After the apples are juiced, the juice has to be pasteurized. At Mercier Orchards, they use two different pasteurization methods. The first process, full pasteurization, heats the juice to 180 degrees, yielding a cider that’s shelf-stable for up to two years. Flash pasteurization, however, only heats the juice very quickly to 161 degrees for a matter of seconds. The flash pasteurized juice retains more flavor but doesn’t last as long.

Modern agricultural science at Mercier Orchards

Exterior shot of Mercier Orchard's store.

Image credit: Select Georgia

Tim Mercier, CEO of Mercier Orchards, has said he believes the company’s willingness to learn, adapt and change are their most important assets, something that Lillard and Flom strongly support.

Years ago, the farm was only open from September to December; now, 12 months a year you can head to the farm and do so much more than buy apples. Beyond the bakery, the café, the winery, and the marketplace, you can also take a cooking class, do a tasting, take a tractor tour with a guide, or get out in the fields and pick fruit yourself. Every year brings new varieties of apples, and they’ve expanded to peaches, blueberries, blackberries, strawberries, and nectarines as well.

So load up your family, and take them up to Mercier Orchards for a day outside, with a cup of hot cider, a fried pie, and see this family farm do modern agricultural science for yourself.

Thank you so much to David Lillard, Ian Flom, and everyone at Mercier Orchards for taking us through the science of apple growing! To keep up with Mercier Orchards, follow them on Facebook and Instagram. Check out their website for the most up to date information (and to place any orders!):

Follow Science ATL on FacebookTwitter, and Instagram for more Awesome Science of Everyday Life features and other science updates!

Atlanta’s Living History: Old-Growth Forests in the City

By Elizabeth Spiers

“Grandmother” Beech, Cascade Springs Nature Preserve, photo © Kathryn Kolb

When I greet Kathryn Kolb near Proctor Creek Trail, she leads me towards a slope, “This little patch right here, is attached to a large tract of old-growth forest. It looks like nothing, but it does have some characteristics that are consistent with areas where we find old forests. There’s a steep slope and narrow stream corridor, so people didn’t disturb the soils here when they started farming and building”. We’ve met to discuss the history and ecological impact of old-growth forests and trees in the Atlanta region.

Kolb has worked with organizations such as The Wilderness Society, Georgia Forestwatch, Georgia Conservancy, and Trees Atlanta to raise awareness and provide education on the important processes and roles that trees can provide. Kolb has been a naturalist for over 30 years in the Southeast United States and is an expert on old-growth forests within the city of Atlanta. 

What Are Old-Growth Forests?

Old growth trees near Atlanta, GA

Old-growth forests still exist in small pockets throughout Atlanta.

Old-growth forests are typically defined as an area of land undisturbed by human agriculture or development for 120 years or more. The soil and plant life in these areas has remained relatively untouched from human influences. 200 years ago, Atlanta was home to an expansive old-growth forest. These forests provide unique ecological features, including large trees, multi-layered canopies, rich soils, and unique biological niches for native species. [Image 1] Kolb explains, “A lot of the trees in old-growth areas are not necessarily older trees, they’re younger trees. It’s possible to tell an area is older from native plants, called indicator species, such as bloodroots, trilliums, and hepatica”. Most of these species have seeds that are not distributed by wind or transported by sticking to larger animals. The seeds are distributed by ants or just fall close to the mother plant, so they are a continuation of original plants and don’t migrate from other areas. An abundance of these ‘indicator species’ signifies the soil and root networks have been mostly undisturbed by development or agriculture.

As Kolb leads me into an area of old-growth forest, the vibrant natural diversity becomes almost immediately apparent. Invasive ivies abundant along the road completely disappear. Within fifteen minutes we encounter beech, pine, sourwood, hickory, oak, black gum, and tulip trees. Kolb has an expert eye, identifying the various species and pointing out each to me as we walk. 

Atlanta’s Biodiverse History

Kolb emphasizes how the history of Atlanta is unique from most other major metro cities in the United States. The primary difference being that Atlanta’s development was relatively late, beginning around 1821, almost 100 years after most other major cities on the eastern seaboard. Shortly after, the Civil War began, and the area stayed in a depressed and rural condition. Wide development and expansion of Atlanta didn’t truly begin until the 1960’s, Kolb explains. The byproduct of this slower development is that Atlanta didn’t go through the sprawling intermediate phase most other cities went through, resulting in the retention of ‘old-growth forest’ throughout metro Atlanta. This is a unique characteristic of a major city in the United States. Few other cities harbor ancient trees and soils that provide such rich biodiversity. The untouched soils and tree growths around Atlanta are not only unique, they also provide important natural resources and biological processes that benefit our city.

In addition to providing a link to the history of the land, Kolb explains that these trees all provide practical resources to our community. One is controlling storm run-off. When tree root networks are removed from an area, the soils are easily washed away by stormwater. However, when the tree root networks are maintained, the roots hold the soil in place, preventing erosion and loss of hill slopes. The rich soils in these older, undisturbed areas also absorb water, preventing the water from flooding down-slope regions. Increases in urban development and concrete abundance, prevent water from being absorbed into the ground, leading to larger amounts of flooding. This is easily seen around the city when giant puddles form on the sides of roads and sidewalks during storms. Areas that have large tree populations are less prone to such issues.

It’s All About the Soil

Image of a forest floor, covered in pinecones, straw, and twigs.

The soils in remnant forests not only absorb storm runoff but contain unique fungi. Those fungi have partnerships with all the other species. “It’s all about the soil”, explains Kolb. During our walk, I notice that the soil does, in fact, feel different underfoot. It is very soft with a thick layer of debris and organic material on top, causing my shoe to sink nearly an inch into the ground as I walk. Microbe and fungi populations within this thick layer of organic material and soil work together in a biodiverse network, promoting the growth and life cycle of native species.

Think of a biodiverse forest network like a city. The roads, people, houses, and stores all work together to provide a thriving community. In a similar way, the trees, fungi, microbes, soil, water, and plants all work together through chemical, biological, and geological processes to help one another thrive and grow. For example, orchids are fully dependent on fungi for their seed germination and life cycle. Without fungi, they cannot reproduce new flowers. And orchids are not alone; many native forest species depend on the interconnected system of tree roots, rotting organic matter, fungi, and microbial populations in the soils that these untouched forests contain. 

Take a Deep Breath

Another benefit to native tree populations and old-growth forests is they clean our air of pollutants through photosynthesis, the process by which plants metabolize energy and grow. Plants convert light energy from the sun into chemical energy that the plants can use as food. In this process, the plants take in carbon dioxide (CO2), water (H2O), and sunlight and then convert those into carbohydrates (CH2O), which the plants use to grow, and oxygen (O2), which goes into our atmosphere. When the plants and trees take in carbon dioxide and release oxygen, they help improve the air quality in our neighborhoods. In 1994, trees in urban forests in Atlanta removed an estimated 1,196 metric tons of air pollution at an estimated value to society of $6.5 million. Larger, older trees such as those in old-growths are especially good at this process and can process a much larger volume of carbon dioxide than younger trees can within a year.

A Living History

Kolb works through organizations and community networks to protect and raise awareness of the utility of forests, but also the aesthetic and emotional value they provide. Through her work and the work of other area naturalists, Atlanta has earned a reputation of being a highly forested city with rich tree canopies. These trees are not only practical resources, they are also a living history of the city of Atlanta. As we walked further into the pocket of forest, we approached a large beech tree, much larger than any of the other ones we had encountered. [Image 2] Kolb estimates based on its size, it may be older than 200 years. To try to get an idea of the tree’s age, we examined the etchings on the tree made by other people decades ago, “Keith + Franklin, 1977”, “1956, Roy F”, “W, 1911.”

Photo collage of etchings on an old beech tree.

Etchings on an old beech tree, showing a living history of Atlanta.

Some of the markings are old enough that they have been stretched to the point of unreadability as the tree has grown. It is a tall, gorgeous sentinel, that has withstood Atlanta’s continuous growth, a larger than life illustration of how these forest remnants are a natural part of our city’s past, present, and (hopefully) future. 

Thank you so much to Kathryn Kolb for taking us through a journey of Atlanta’s biodiverse history! Learn more about Atlanta’s public old-growth forests here, visit Kathryn’s website, and get involved with EcoAddendum, which raises awareness of Georgia’s natural environment. Follow Science ATL on FacebookTwitter, and Instagram for more Awesome Science of Everyday Life features and other science updates!

The Science Behind Honey with Urban Honey Bee Project

By: Brielle James
Photos provided by Jennifer Leavey

On the roof of the Georgia Institute of Technology’s Clough Undergraduate Learning Commons sit four waist-high stacks of white boxes. For about 200,000 Western honey bees (Apis mellifera), these boxes are considered home. Together, the boxes (known as supers or hive boxes, each containing numerous wooden frames for the bees to build their honeycomb on) form four beehives belonging to the Georgia Tech Urban Honey Bee Project.

Since the Spring of 2013, the Urban Honey Bee Project, led by Dr. Jennifer Leavey, has maintained anywhere between two and seven hives on the roof of this building. “Once I brought bees to campus,” Dr. Leavey said, “people were really interested in using them for research and learning how to keep bees.” Western honey bees, which originated in eastern Europe, are the most widely managed bees in the world, supplying honey for a worldwide commercial market. How they do this is driven mainly by their biology, allowing them to work together as pint-sized chemists to create the honey we all love.


Survival of the colony and honey production requires a group effort from all of the bees in the hive. In every honey bee hive, Dr. Leavey explained, there are 3 types of bees: the queen, worker bees, and drones. Queen bees are responsible for laying and fertilizing eggs (known as brood) to grow the colony.

Pointing out the queen bee in the hive

Pointing out the queen bee in the hive

Worker bees, which are all nonreproducing female bees, make up the majority of the colony. “Worker bees do different jobs at different ages,” Dr. Leavey says. Young bees work inside of the hive as “nurse” bees to eggs and larvae, queen attendants, and hive janitors. As the bees age, they transition to guard bees at the hive entrance and then foragers. 

Lastly, there are the drones, which are male bees whose only job is to mate with queens from other colonies. Compared to worker bees, there are not many drone bees in the colony. “Depending on the time of year there are none of them [drone bees] in the hive. They kick them out in the fall. They don’t feed them, because they’ll raise more in the spring,” Dr. Leavey says. 


The first step in honey production relies on the forager bees collecting nectar from plants. Honey bees collect the nectar in their honey stomachs, which contain a digestive enzyme called invertase. This enzyme breaks down the nectar’s sugar molecules (splitting sucrose into fructose and glucose). Upon returning to the hive, the forager bees then regurgitate the nectar into cells of the honeycomb. The nectar is repeatedly ingested and regurgitated by the hive bees, adding additional invertase to continue breaking it down.

“[Invertase] is the same enzyme that’s used in the sugar industry to take the fructose produced by corn and produce high fructose corn syrup,” Dr. Leavey says. “So chemically it’s almost impossible to distinguish high fructose corn syrup from honey.” The only way to tell that honey is, in fact, honey is by the residual pollen in it, but big honey producers ultra-filter their honey to sell honey that appears clear and perfect. As a result, “they’ve removed the only thing that distinguishes honey from sugar syrup.”

Chemically, it’s almost impossible to distinguish high fructose corn syrup from honey.

How much honey a hive produces depends on the colony and can vary yearly, but Dr. Leavey says this usually ranges from 50 to 100 lbs of honey per year. She usually takes less than 50 lbs of excess honey from her hives in the mid-summer after the main nectar flow. To do this, she must first harvest the honey. “Sometimes we just take frame by frame,” Dr. Leavey explained. “We’ve got a soft brush and we’ll just brush any bees off and then put [the frame] in a box with a lid.” As she described this initial step, she also shared one of her tricks to harvesting – “if you do it at a time when stuff is still blooming, the bees don’t get mad,” she said. Next, the honey must be extracted out of the honeycomb. Dr. Leavey explained that “if you remove [the honey] from the comb, you can put the comb back for the bees and then they don’t have to make more wax.” A nice way to reduce, reuse, and recycle! 

To extract the honey, students at the Urban Honey Bee Project use a knife to cut the wax off of the comb that the bees have used to seal the honey. The comb then goes into an extractor, a centrifuge that spins the honey out of the comb using centrifugal force. The honey slowly drips to the bottom of the extractor, which has a spout through which the honey can be collected. Beekeepers then strain the honey through screens to filter out any pieces of remaining wax. Wax and pollen can be starting points for crystal formation (solid sugar granules) in the honey, making it gritty and less desirable to eat. Crystallized honey also comes with risks. “If your regular honey, that’s well dissolved, is 83% sugar and then now you’ve got crystals forming, the resulting fluid will have higher water content. If you have higher water content, you can get fermentation to start to occur,” explained Dr. Leavey.


Within the honey bees’ hive, there are different storage areas – honey stores, pollen stores, and brood. “The brood area [in the hive] is basically, in 3D space, the size of a football…and then above the football would be where all the honey is stored and then kind of to the sides and underneath is where the pollen tends to be stored,” Dr. Leavey explained. The brood area is home to all of the baby bees as they grow, while the honey and pollen stores provide the colony with food. “When you open up a beehive, in general, you’ll see all the bees in the brood area, because the nurse bees are really busy there,” Dr. Leavey says. It is there where the queen lays her eggs, which hatch into larvae. Once hatched, nurse bees feed the larvae royal jelly. Royal jelly is “the breast milk of bees,” according to Dr. Leavey, a substance full of vitamins and growth factors produced by bees from glands in their neck. Larvae eventually transition to a diet of pollen and honey before they are capped in the honeycomb to undergo metamorphosis into an adult bee.

Interestingly, queen bees are fed royal jelly their whole lives. “The only difference between a queen bee and a worker bee is what they’re fed. Once the workers start getting fed pollen it changes gene expression and it changes their development,” Dr. Leavey explained. This difference in diet leads to distinct behavioral characteristics. For example, the bigger, fertile, longer-lived queen bees leave the hive to mate, unlike the smaller, sterile worker bees.

In the hive are also the bees’ pollen stores, known as “bee bread.” Bee bread is fermented flower pollen and is the primary source of protein for the hive. Forager bees collect the pollen from flowers and groom it off of their body into “pollen baskets” on their hind legs. “They do add a little bit of nectar to the pollen to make it this dough-ball of pollen that they carry,” Dr. Leavey explained. This pollen load is then carried back to the hive and packed into comb cells for storage. The bees add nectar, honey, and saliva to the pollen when they pack it. “You can kind of smell it when you open a hive. It has that yeasty smell. There are microbes that mix with the pollen and ferment it a little bit and that’s what they use to feed the larvae,” Dr. Leavey says.


While the complexities of a honey bee colony allow it to thrive, these complexities also make it easy to disrupt. “It’s very hard to keep bees now,” Dr. Leavey says. “There are three contributors to colony collapse. It’s pesticide exposure, disease, and poor nutrition.” The latter results from a lack of habitat and appropriate floral resources for the bees.

Help support bees by planting bee-friendly flowers and trees

To help support the bee population, Dr. Leavey suggests planting flowers that are easy to look at, like sunflowers, which a lot of bee species visit. She also recommends reading lists of region-specific pollinator-friendly plant species published by the Xerces Society and planting trees, specifically tulip poplar trees in Atlanta. “I think trees are great just because one tree has so many flowers,” she says.

The Urban Honey Bee Project is committed to supporting these pollinators and the environments that they need to thrive through a wide range of research and outreach efforts to help local community partners establish their own beehives. To keep up with the Urban Honey Bee Project, checking in on the bees via the “bee-cam” or getting involved as a volunteer, visit their website. You can also follow them on Facebook for more updates.

Thank you to Jennifer Leavey and everyone at Georgia Tech Urban Honey Bee Project for teaching us about the awesome science of honey production. Follow Science ATL on FacebookTwitter, and Instagram for more Awesome Science of Everyday Life features and other science updates!

The Science of Good Dirt at CompostNow

By Donna McDermott

King of Crops farm

I visited King of Crops farm on the first cool morning of September. Last night’s rain had left a cloudy, golden glow over rows of blueberry, muscadine, and persimmon that would soon become popsicles sold under rainbow umbrellas. But I didn’t go to King of Crops for the fruit. I was there to meet David Paull, CompostNow co-founder and CIO.

About CompostNow

CompostNow collects food scraps from residents and businesses to help them reduce waste and support local gardens. The farm where I met Paull is less than an hour from Midtown, yet nature sprawled out around us with a vigor you rarely see in a city garden. In amongst the fields were tulip tree saplings, goldenrod blooms, and, of course, decay. This is the kind of decay that makes room for new growth.

David Paull, CompostNow co-founder and CIO

David Paull, CompostNow co-founder and CIO

As we start our conversation, Paull speaks about his longtime commitment to agriculture that works in harmony with nature. These days, his goal with CompostNow is “to develop the vitality in our soil systems on a larger scale.” His goal of cultivating healthy gardens appears to have grown and flowered. Pokeberry branches fruiting around the skeleton of a long-abandoned greenhouse are one of the few signs that, years ago, this land was home to an ornamental nursery.

The compost piles are about as tall as I am, with dimensions slightly smaller than a school bus. The pile closest to the road is flecked with mysterious white and green streaks. Piles farther from the road are older, richer, and have become a uniform dark brown. As we walk toward the compost, I smell a slight, mellow funk. This is decomposition at work.

Piles and Piles of Compost

Piles of compost at CompostNow

This isn’t just any dirt.

The labor of composting is largely here, right at the piles. Workers pick out trash that won’t decompose, filtering out the mistakes that sneak into composters’ buckets. (Or, maybe “mistakes” is the wrong word. Unusual finds in this compost pile include a life-size steel dog statue.) Once the piles are cleared of contaminants, microbes take over the work.

Microbes are organisms that are too small for the human eye to see. This group includes bacteria, small funguses, algae, and other single-celled creatures. And there is a diverse microbe community living in all healthy soil. This microbe community helps plants absorb soil nutrients and also decompose. Different species of microbes grow at different temperatures. Paull measures a pile where microbes are thriving at 136°, while a freshly turned pile would have microbes that work best around 150°. High temperatures like these are essential for safely composting materials like meat and dairy. In contrast, home compost piles are smaller and therefore colder, so meat and dairy products often can’t be included. In a colder compost pile, meat and dairy products don’t decompose all the way. Meat and dairy scraps breed different communities of microbes that can be harmful to human health. These differences in microbe community are why the small compost pile in someone’s backyard is likely to only contain raw vegetable scraps.

The Science of Good Dirt

Temperature gauge monitoring the temperature of a compost pile

Monitoring the temperature of the compost pile.

CompostNow has the capacity for huge compost piles that are consistently maintained by skilled workers. Because these piles always reach high temperatures, consumers can safely include meat and dairy products in their CompostNow bins. The workers at CompostNow carefully control pile temperature by accounting for a range of factors: pile size, the frequency with which the piles are turned, airflow through the piles, water content. It’s this maintenance that makes composting so easy since customers don’t need to think about which foods are going into their CompostNow bin.

The microbe decomposers take their time in fully decomposing food scraps down into soil nutrients. These piles will mature for about nine months before they’re ready. Most of the compost here will stay on the King of Crops farm, helping to fertilize the soil that has long been neglected. CompostNow also sends compost to community gardens around Atlanta and to the customers that submit compost in the first place. Give out food scraps, receive soil nutrients in return. This process of rot and rejuvenation might not seem romantic, but compost piles are nature at its finest. Cycles of growth are regenerated here, by the slow, steady effort of humans and bacteria and fungi.

The Cost of Composting

David Paull, CompostNow co-founder and CIO explaining the cost and challenges of composting

The biggest challenge of composting is the stage where waiting isn’t an option: the very beginning. The logistics of moving food scraps from dinner plates to dump trucks are complicated. To solve this puzzle, CompostNow uses their own original software to create routes between composting customers while tracking data on the company’s collection and production. The customers are the fuel behind this operation. Customers’ food scraps generate nutrient-rich soil while their monthly fees support the staff that maintains healthy compost piles. Still, most customers never see the farm where their waste turns into new food. So why do customers sign up?

I signed up for CompostNow for the same reasons that David Paull began community composting in Atlanta in the first place. As Paull describes it, agriculture is “the basis of a healthy community.” But unfortunately, our mainstream agriculture system “goes totally against the way that we could be producing food and how we think about our waste in general.” Paull points out that it’s a problem to think of food scraps as waste, yet many people do; 97% of food scraps generated in the US are dumped in landfills and the US produces more than 100,000 tons of landfill waste annually. These tons of waste are costly.

David Paull examining a compost pile

The cost of composting goes toward building a sustainable culture.


Paull explains that some potential customers balk at the price of monthly compost pickups. He argues that throwing food scraps in the trash can isn’t free, either. (In Atlanta, the base rate for garbage pickup is more than $300 per household each year.) The cost of conventional trash pick up is especially high if you consider the long-term costs. For example, Paull lists, “The cost to maintain those landfills, the cost of environmental degradation, the cost of, you know, the fact that our climate is changing rapidly. We’re experiencing more extreme weather conditions than we have ever before… So, if… you think that you don’t pay for waste, you absolutely pay for waste.” In Paull’s opinion, the cost of composting goes toward building a sustainable culture.

Sustainability is not just a matter of microbes and trash and dirt; it’s about people. For healthy ecosystems to thrive, the people inside them need to, also. At CompostNow, Paull explains, “People have to be able to have health insurance. They have to be able to go from being a college student… to someone that’s interested in developing a life with potentially a family.” This ethos is why CompostNow’s minimum wage is $15 an hour. This respect for workers is a heartening contrast from conventional trash pickup services. Though conventional trash collectors make a similar wage (median hourly wage in the US is $17/ hour), they risk injury and death in the collection process. Trash and recycling collection is one of the most dangerous jobs in the country, according to the US Bureau of Labor Statistics. In contrast, CompostNow’s commitment to the environment includes prioritizing the needs of people in their community, including both those on the farm and out in the world.

Community & Sustainability

King of Compost sign next to a compost pile

Connecting with community members about sustainability is the foundation of CompostNow. Paull describes how exciting it is to host conversations with composters: “If we can stand at a farmer’s market and be the enthusiastic champions of compost, where someone can come up to our table and literally exclaim their passion for their backyard compost pile to us and just share that to us, that is an amazing opportunity and we treat that very seriously.”

Get Involved

Would you like to join in on the compost conversation? You can visit CompostNow online. If you’re extra excited — or extra tentative— you can talk to a CompostNow expert at the Grant Park Farmer’s Market, Peachtree Road Markets, or Freedom Farmers Market. Global ecosystems may be changing rapidly, but businesses like CompostNow are a nice reminder that there’s still time to connect to your environment. Don’t miss the opportunity to walk down tree-lined park paths early in the morning, hot coffee in hand, and ask a stranger what to do with your dirt.

Thank you to CompostNow and David Paull for walking us through the science of good dirt. Stay tuned to our website, Facebook, Twitter, and Instagram for more Awesome Science of Everyday Life features and other science updates!

The Science of Cross Country Running Training

By Owen Beck

“Is this normal?” asked Agnes Scott College’s newest head Cross Country Coach, Molly Carl, referring to a 90-degree fall day last year, “Shouldn’t it have cooled off a bit by now?” Welcome to Hotlanta!

Coach Carl

While this Northerner may still be acclimating to Georgia’s sweltering heat, Coach Carl is very familiar with successful cross country running. Prior to arriving to Agnes Scott College, Coach Carl was a standout cross country and track athlete at Southern Maine University. Following undergrad, she was an Assistant Cross Country Coach while obtaining her Master’s degree in Exercise and Sport Studies at Smith College. Coupling her experiences and enthusiasm for the sport, Coach Carl is ready to lead the Agnes Scott Scotties to cross country prominence.

Collegiate cross country running is usually between 2 to 3.7 miles on non-paved paths and is an intensively aerobic exercise. In other words, it is exercise that improves and requires the body to absorb oxygen efficiently. Well acquainted with how to get runners prepared to compete, Coach Carl came to Agnes Scott with “a vision and a plan for the program and it got people excited to join forces with her” according to Agnes Scott College’s Cross Country Graduate Assistant Coach, River Bonds.

Cross Country Training

Coach Carl trains Agnes Scott athletes with the same science-based training program that led her to All-American status as a collegiate athlete. Like an astute writer, she uses an outline to guide the training schedule. “I see where our championship races are, then work backwards,” explains Coach Carl. This approach of reverse chronological planning is standard for coaches from all sports to properly peak their athletes for late-season competitions – Agnes Scott’s championship cross country races are usually in November. Next, Coach Carl lays out four, six-week training phases to prepare her athletes for November’s races. In each training phase, specific workouts are featured to enhance certain body processes that improve distance-running performance.

Naturally, the initial training phase is the easiest, as its primary goal is to re-acclimate the athletes to running consistently. Coach Carl may advise athletes who did not run competitively during the spring to build up to running 15 to 30 miles per week over this phase. Not only does this phase prepare athletes for more rigorous training, but it elicits adaptation that improve distance-running performance. For example, to keep running, leg muscles need a constant supply of oxygen-rich blood, like a car engine needs gas. Consistent running increases the stroke volume, the volume of blood pumped from the heart with each beat, which improves the body’s ability to circulate oxygenated blood to leg muscles and keep running.

Once the initial adaptations are in motion, Coach Carl’s athletes transition to the second training phase, where “repetition” workouts are introduced to their weekly schedule. Repetition workouts entail running relatively short and fast intervals with long recoveries between repetitions. For cross country athletes, repetitions workouts are generally 200 to 400 m (a half to full length of an outdoor track) at current mile race pace with 1 to 8-minutes rest. The primary goal of these workouts is to improve athlete’s running form, since optimizing form maximizes performance. Improved running form may decrease the rate of energy that an athlete expends while running a given speed. This is analogous to how much gas a car burns while driving at a constant speed (less gas is better). While considering other factors, athletes who consume less energy to run at a given speed can outperform their competitors by having the ability to run farther at a given speed and faster at given aerobic intensity.

Girls Running Cross Country

“…Then I get them for the next two phases… when they are back on campus” continues Coach Carl. You read that correctly, 12 of the collegiate 24-week training program is completed prior to the first day of practice. “You have to be intrinsically motivated to do well”, she adds. Indeed.

Athletes are welcomed back to school by the most difficult training phase. By now, each week athletes run multiple easy days, two structured workouts (e.g. repetition workouts), and a long run. Long runs are ~25% of the respective athlete’s weekly mileage (e.g. ~10 mile long run for an athlete running 40 miles a week) and serve to improve the number of blood vessels that transport oxygen to exercising muscles. Notably, the primary goal of the third training phase is to increase the maximum rate of oxygen that an athlete can uptake, transport, and utilize to generate energy. Much like how football players love 40-yard dash times, this is the measure that endurance athletes obsess over due to its close relationship with distance-running performance. To increase her athletes’ maximum rate of oxygen uptake, Coach Carl has the team perform classic “interval” workouts that consist of 3-5 minutes of intense running with 2-3 minutes rest between intervals.

Another intense, albeit a more enjoyable, aspect of phase three are the beginning of cross country races. Cross country races are generally 2.0 to 3.7 miles and start around the end of August or beginning of September. Ideally, Coach Carl’s team runs 5 to 6 races before the November’s championships.

The final training phase is intended to simultaneously improve another physiological process and freshen the athletes up for the key races. Physiologically, to sustain a relatively fast running speed, athletes expend energy without the presence of oxygen at the muscle-level. If athletes expend too much of this energy source, their blood will likely become more acidic than normal, resulting in the sudden feeling of having heavy legs. To train the body to buffer this race-slowing feeling, athlete’s run workouts include a moderately hard continuous run (e.g. 20 minutes) or multiple repeats with short rest (e.g. 5-minute intervals with 1-minute rest). These workouts are perfect for the final training-phase because they are also relatively easy to recover from due to their controlled intensity. In the last few weeks of the season, athletes decrease their overall weekly mileage to enter the championship races rested and ready.

Even though this science-based training approach develops key physiological parameters that influence distance-running performance, Coach Carl carefully customizes the training of her athletes as the season progresses on an athlete-by-athlete basis. “You cannot just plug a human into a system and be like this should totally work out” she says with amusement. Subtleties like altering training to handle life events, mimicking training environments to resemble race courses (e.g. incorporating hills to prepare for hilly courses), and developing race plans that cater to each athlete’s strength are just a few ways that Coach Carl artfully brings science-based training to life.

Whether you are preparing to get back into shape, run in the world’s largest 10-kilometer race (Atlanta Track Club’s Peachtree Road Race), or guide athletes through their cross-country season, these science-based training methods can be helpful. After all, what do you have to lose? Except for a few minutes on your next race.

The Science of Spirits with Old Fourth Distillery

By Kellie Vinal

Old Fourth Distillery

Old Fourth Distillery, nestled in the heart of Old Fourth Ward, is well known around Atlanta as a purveyor of hand-made vodka, gin, and their signature ginger lemon liqueur, Lawn Dart.

It hasn’t always been easy to get locally sourced spirits, though. In fact, Old Fourth is the first legal Atlanta distillery in over 100 years, due to the temperance movement that forced prolific distillers like R.M. Rose & Company out of the city.

Jeff explaining antiques on walls.

“There’s a really rich history of distilling in Atlanta,” says Jeff Moore, one of the two founding brothers of O4D. If you look closely, you’ll notice that the distillery is teeming with artifacts of the distillers that came before them – some bought, others donated by generous collectors and enthusiasts.

The Moore brothers have a refreshing reverence for history, honoring the folks that pioneered their craft in all they do. Each aspect of the distillery – from the construction of the physical space, the antiques filling each nook and cranny, the design of their bottles and labels, and the spirits they create — has been thoughtfully considered. Each bit is a nod to history, an appreciation of the past.

Jeff with liquor bottles.

For instance, many of the materials used to build the space were salvaged and repurposed from the demolition of John B. Gordon Elementary School, a historic, once bustling East Atlanta school built in the early 1900s. The distillery’s marble countertops once served as dividers of the school’s boys’ and girls’ bathroom stalls, and is said to have come from the same batch of marble — mined in Tate, Georgia at the turn of the century — that the Lincoln Memorial is made of.

Jeff acknowledges that although it takes significant work to upcycle old materials in place of buying new ones, it’s worth it.

“We talk about being stewards of the materials that we use,” he says.

The Journey from Yeast to Spirits

Jeff explaining beer-making.

The Moore brothers’ thoughtfulness extends to the science behind their craft, too, and necessarily so – creating spirits is actually more complicated than you might think.

At its core, distillation is the process of strategically separating liquids through condensation (which means converting water vapor into liquid water) and evaporation (converting liquid to a gas). But to make gin, vodka, or bourbon, for that matter, it all begins with yeast.

Similar to wine- or beer-making, creating liquor begins with fermentation, or the conversion of sugar to alcohol and carbon dioxide. At O4D, they’ve developed a specific protocol for each type of liquor they make, each requiring a particular strain and precise amount of yeast.

Jeff with Fermentation equipment

“We could take the exact same recipe that we made our vodka out of and put another yeast strain in and it’ll give us a completely different finish,” says Jeff. “It’s really, really interesting, how the complexities work.”

As such, each batch of yeast must be fed and grown precisely. When making vodka, for instance, Jeff and his team add carefully measured amounts of cane sugar, nutrients, calcium carbonate (to balance the pH), and a few other ingredients to their yeast, and then grow the cultures at specific controlled temperatures.

The yeast undergo multiple cycles of heating and cooling over the next five days, coordinated by human-powered thermostats and control valves galore. As the yeast convert sugar into alcohol, they eventually run out of sugar to consume and ultimately create a 13% alcohol mixture.

“We call it Edgewood hard soda,” Jeff jokes. “It’s [basically] 13% alcohol cane soda, if you will. But we don’t stop there.”

13% Cane Beer

The thing is, yeast don’t like living long-term in 13% alcohol. It’s toxic to them.

That’s where distilling comes in. To get to that higher alcohol content, Jeff and his crew must physically separate the alcohol from the rest of the mixture.

Basically, since the boiling point of alcohol is lower than water, distillers can strategically evaporate the alcohol from their mixture. The next step is to collect the vapors, separate them from the water, and cool them down, thus condensing the vapor back into a liquid. This is all done in a device called a still. At O4D, they use a custom, handmade CARL copper still.

It seems like magic, but it’s science: in a single run, the 13% alcohol mixture becomes 50% alcohol. Jeff and his crew then run the mixture twice more through their still.

For each and every run, the still operators keep detailed logs, tracking which batch of sugar they used, how much of each ingredient they used, any time or temperature tweaks they made throughout the process, and characteristics of the final product.

Heads, Hearts, and Tails

The evaporation process of distilling isn’t completely clear-cut – the alcohol you want is inevitably mixed in with some chemicals you don’t want. Jeff explains that with careful temperature and timing control, he can separate out the parts they don’t want and keep the parts they do.

“We’re pulling off three main components [at different temperatures],” Jeff explains. “The heads, the hearts, and the tails. What you want to drink are hearts.”

What comes off first at the lowest temperatures – the heads – are quite toxic, with a distinctly chemical-y smell. The heads get sent off (no joke!) to fuel companies to repurpose for methanol. What comes off last at the highest temperatures – the tails – are lower alcohol content and contain unappetizing oily substances. “It’s very … oily band-aids,” Jeff laughs.

Heads, Hearts, and Tails bottles

“You’re always going to have some heads and some tails. Always. There’s no getting rid of it all.” Jeff continues, “How you tell is by taste, touch, and smell.”

Diagram of Heads, Hearts, and Tails
As with most things, it’s all about finding balance. The optimal middle portion — the hearts — undergoes a few more finishing steps before it’s ready to be bottled, including a sometimes week-long “resting” phase to let everything settle.

Jeff gestures to the hearts as he says, “when we’re distilling, this is the magic. It all boils down to this.”

Experimenters by Trade

The lab.

When it comes to making spirits, there’s both an art and a science to it. Vodka, gin, and bourbon require very different starting materials, temperatures, time schedules, and manipulations along the way. No two gins are exactly the same, either.

Crushing juniper berries and Jeff explaining his experimentations.

“Gin can have literally anything in it. The only thing that gin has to have in it from a legal standpoint is juniper berries,” Jeff says. “Other than that, the sky is the limit. And believe me, we have tested that theory.”

Old Fourth Distillery Gin BottleOn those long days spent waiting for those heads, hearts, and tails to come off the still, Jeff and his colleagues fill the idle time with experiments on a smaller 20-liter still. They play around with different ingredients, temperatures, and flavors, always chasing their curiosities and, ultimately, enhancing their craft.

“The gin that we sell today is my greatest accomplishment in terms of distilling,” Jeff says. He gestures to a shelf filled with bottles. “Up here, we have about a dozen versions of gin.” He continues, “I’ve got a moleskine notebook stashed somewhere and every single one of these has got three pages of notes on how to make it.”

Giving Back

Since Old Fourth Distillery opened its doors in 2014, they’ve made an effort to connect with their community through tours, tastings, and community collaborations. This summer, for instance, they teamed up with Atlanta United to create a limited edition gin that has been enthusiastically received by fans.

Old Fourth finds other ways to give back as well, like maintaining the gravesite of historic distiller R.M. Rose, which is nearby at Oakland Cemetery. They’ve made gin in Rose’s honor, using juniper berries picked near his gravesite. O4D has also forged a friendship with their upstairs neighbor, The Railroad Model Club of Atlanta, periodically helping them with upgrades and generally supporting their endeavors.

With so much intention and precision behind all they do, O4D is poised to serve southern spirits to Atlanta for years to come. To keep up with new releases and updates or to schedule a tour, visit the O4D website. You can also connect with them via Facebook or Twitter.

Old Fourth Distillery | Edgewood Avenue

If you’re curious about the history of distilling in Atlanta, Jeff recommends the book Prohibition in Atlanta by Ron Smith and Mary O. Boyle.