From Cherry to Cup: The Science Behind Your Morning Coffee
S02:E05

From Cherry to Cup: The Science Behind Your Morning Coffee

Athens, GA
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Episode description

From Cherry to Cup: The Science Behind Your Morning Coffee

Episode Description

Most of us start the day with a cup of coffee and never think about the plant it came from. Dr. Leo Lombardini has thought about it for years. Head of the Horticulture Department at the University of Georgia and former director of the Borlaug Center for World Coffee at Texas A&M, Leo walks Ping through the whole journey: from a tiny white flower on a tropical shrub to the seed inside a coffee cherry to the roasted bean in your grinder.

Along the way you will learn why only about three of the 133 species in the Coffea genus end up in your cup, what “shade-grown, mountain-grown” actually does to flavor, and how three different processing methods (natural, honey, and washed) change a coffee before it ever reaches a roaster. Leo also explains a fact that surprises most drinkers: caffeine content barely moves during roasting, so a dark roast is not a stronger jolt.

By the end, Leo leaves every coffee drinker with a simple habit for the next trip to the store, and a reminder that behind every bag is a farmer who spent long days in the field. This one is for anyone who loves their morning ritual and wants to taste it a little differently tomorrow.

Listen Time: 55:23 Follow Along with the Transcript

In This Episode

Guest

Dr. Leo Lombardini has been Head of the Department of Horticulture at the University of Georgia since 2019. A native of Florence, Italy, Leo earned his PhD at Michigan State and spent years at Texas A&M, where he directed the Borlaug Center for World Coffee and studied pecan for roughly 15 years. His research spans coffee and pecan, and he co-led a USAID-funded project helping nine Central American countries fight coffee leaf rust.

Main Topics

  • Welcome to Blooms and Beyond (00:00)
  • Meet Dr. Leo Lombardini: from Tuscany to horticulture (01:10)
  • Pecan and the chestnut: a favorite species (05:24)
  • How Leo got into coffee research (08:32)
  • How studying coffee changed the way he drinks it (14:46)
  • Where coffee comes from: species and geography (18:51)
  • What coffee plants need to grow (23:58)
  • Seeing a coffee plant in flower (27:51)
  • From plant to cup: harvest and processing (29:10)
  • The art of roasting (37:57)
  • What every coffee drinker should remember (46:37)
  • The future of UGA Horticulture (49:52)
  • Where to learn more (53:00)
  • Closing and credits (54:28)

Key Highlights

  • A childhood spent resurrecting an abandoned Tuscan vineyard and olive grove is where Leo’s love of plants began, long before video games gave kids anything else to do.
  • Coffee leaf rust is the crop’s worst disease. A 2012–2013 outbreak in Central America was severe enough that economists linked the resulting job losses to a spike in migration to the United States, which is part of why USAID funded the response.
  • Coffee grows commercially in only two U.S. states: Hawaii and a small amount of boutique production in California. Yet coffee supports more than two million American jobs.
  • The coffee “bean” is actually a seed. Each coffee cherry holds two seeds facing each other, which is why a bean has one flat side and one curved side.
  • Three processing methods (natural, honey, and washed) each leave a different chemical signature on the seed before roasting even begins.
  • Caffeine is already in the green bean at about 1 to 1.5% of dry weight, and it survives roasting. Acidity, a prized quality trait, is what drops the longer beans stay in the roaster.

Key Quotes

“So most of the coffee we drink, certainly specialty coffee, comes from the Coffea arabica species, which is one of 133 species in the Coffea genus.” Dr. Leo Lombardini

“According to statistics, there are over two million jobs in the United States that revolve around coffee.” Dr. Leo Lombardini

“When you look at a coffee bean, one side is flat and one side is curved, because the two flat sides face each other.” Dr. Leo Lombardini

“If the coffee is good, you literally don’t have to add any sugar or any creamer or milk or whatever. You just drink it straight, and that’s really how you can evaluate the quality of coffee.” Dr. Leo Lombardini

“There’s so much work behind a cup of coffee, and so much sweat, and time spent in the field, just like for all horticulture crops. Never forget that behind anything we eat, there’s a farmer.” Dr. Leo Lombardini

Educational Highlights

The Coffea genus. There are 133 species of coffee, most of them native to Africa, and Madagascar alone holds 67 of them. Only about three are cultivated: Coffea arabica (roughly 65% of world consumption), Coffea canephora, known as Robusta (about 35%), and Coffea liberica (under 1%, mostly consumed locally). Arabica is prized because it is the mildest.

Arabica vs. Robusta. Arabica came from the western highlands of Ethiopia, a cool, cloudy, high-altitude cloud forest, and it evolved as a shade plant under larger trees. That is why shade-grown, mountain-grown Arabica reaches the highest quality, with ideal temperatures around 70 to 80 degrees. Robusta comes from lowland equatorial Africa across a much larger range, so it tolerates heat and resists pests and diseases better thanks to a broader genetic pool. Many modern Arabica varieties carry a little Robusta ancestry from hybridization that added disease resistance.

Coffee leaf rust. A fungal disease and the worst threat to the coffee crop. The 2012–2013 Central American outbreak combined climate, new fungal strains, and economic pressure into what Leo calls a “perfect storm.”

The coffee cherry. The fruit resembles a cherry, but unlike a cherry it holds two seeds surrounded by a sugary, watery pulp. Because that pulp ferments and rots fast once the fruit is bruised at harvest, processing has to start immediately.

Three ways to process. Natural: whole fruits dry in the sun on patios or raised beds for two to three weeks, and the pulp dries onto the seed, common where water is scarce, such as Yemen. Honey: a depulper removes the pulp, and the seeds dry with their sticky mucilage (a pectin, the same kind used for jams) still on. Washed: the pulp is removed and the seeds soak in water tanks for 24 to 48 hours, where natural yeasts ferment and break down the mucilage. After any method, seeds are dried to 10 to 12% moisture so they will not germinate or spoil.

Green coffee. Beans are shipped unroasted in 60-kilogram bags. Green beans are hard, taste grassy, and smell nothing like coffee. Only roasting develops the familiar aroma and flavor.

Roasting: time and temperature. Drum roasters work like a clothes dryer at about 400 degrees Fahrenheit, with each cycle running roughly 18 to 22 minutes. Roasters trade time against temperature to hit a target roast level. Caffeine (about 1 to 1.5% of the dry bean) is stable and does not change during roasting. Acidity, counterintuitively a marker of high quality in coffee, decreases the longer beans roast, so light-to-medium roasts let you taste a coffee’s best traits.

Why caffeine is there at all. Caffeine is an alkaloid the plant produces as a natural deterrent against pests and diseases, packed most heavily into the seeds to protect the next generation.

Reading the label. “100% Arabica” tells you something about quality. A bag that says only “100% coffee” means some Robusta is blended in.

Resources & Links

  • Website: bandbpod.com
  • UGA Department of Horticulture: hort.caes.uga.edu (search “horticulture UGA” for faculty profiles and academic programs)
  • Atlanta Botanical Garden: look for live coffee plants in the tropical greenhouse
  • Specialty Coffee Association: industry conference and coffee education
  • World Coffee Research: research partner on the Central American coffee leaf rust effort
  • Norman Borlaug Institute for International Agriculture, Texas A&M University: home of the USAID-funded coffee project Leo co-led

About Blooms and Beyond

Blooms and Beyond explores plant history, culture, and management through the lens of science. Whether you’re a commercial grower seeking practical solutions, a student exploring careers in horticulture, or simply someone who loves plants and their stories, there’s something here for you. Hosted by Dr. Ping Yu of the University of Georgia, each episode features interviews with experts who share enchanting stories, cutting-edge research, and practical wisdom from the world of horticulture.

Your benefit: After each episode, commercial growers will have at least one useful tip for their operation, and plant enthusiasts will have an interesting fact to share. That’s how we spread plant power to more people and make our environment a little better.

Credits

Host: Dr. Ping Yu Producer: Rich Braman Guest: Dr. Leo Lombardini, Head, UGA Department of Horticulture

Episode Release Date: July 5, 2026 Episode Length: 55:23

“Till next time, stay healthy and go plants!” 🌱

0:00Welcome to Blooms and Beyond
1:10Meet Dr. Leo Lombardini: From Tuscany
5:24Pecan and the Chestnut: A Favorite Species
8:32How Leo Got Into Coffee Research
14:46How Studying Coffee Changed His Cup
18:51Where Coffee Comes From: Species and Geography
23:58What Coffee Plants Need to Grow
27:51Seeing a Coffee Plant in Flower
29:10From Plant to Cup: Harvest and Processing
37:57The Art of Roasting
46:37What Every Coffee Drinker Should Remember
49:52The Future of UGA Horticulture
53:00Where to Learn More
54:28Closing and Credits