Host: Dr. Ping Yu, UGA Department of Horticulture Guest: Dr. Leo Lombardini, Head, UGA Department of Horticulture (coffee and pecan researcher) Producer: Rich Braman Episode: S02E05 , Blooms and Beyond, Season 2 Duration: 55:23 Air Date: July 5, 2026
Welcome to the Show
Ping Yu: Well, hello, everyone. Welcome to the Blooms and Beyond podcast, a podcast that uncovers plant history, culture, and management through the lens of science. I’m your host, Dr. Ping Yu. How’s everyone doing today?
I am doing great, because here I have one of my favorite people, my dear horticulturist colleague and friend, and also my boss, Dr. Leo Lombardini, here with me today on the show. And we’re going to talk about one of the most fun and exciting topics: coffee. I know folks out there listening to this episode, many of you, like me, have to start your day with a cup of coffee.
Our speaker today is an expert on coffee with many years of research experience and, of course, tons of fascinating stories and a lot of scientific knowledge to share, to help us understand coffee on a different level. So I don’t want to steal any more thunder from our speaker today. Let’s just jump right into it. Without further ado, here is my conversation with Dr. Leo Lombardini. I hope you enjoy it.
Meet Dr. Leo Lombardini: From Tuscany to Horticulture
Ping Yu: So, hey, Leo, welcome to the podcast.
Leo Lombardini: Yes.
Ping Yu: But first, let’s start off with the introduction. Can you tell our audience a little bit about who you are and what you do?
Leo Lombardini: Yes, of course. It’s my pleasure, and thank you so much for the invitation. I’m very excited about this opportunity. My name is Leo Leonardo Lombardini. I am currently the head of the Horticulture Department here at the University of Georgia. I’ve had this position since 2019.
I’m a native Italian. I grew up in Tuscany, grew up in Florence, and then I came to the United States a long time ago, thirty years ago, to work on my PhD at Michigan State University, and then moved around the country a lot. I spent a lot of time at Texas A&M, just like you. That’s where we met, and became very, very acquainted and close. And then, of course, even more so since you joined UGA. So it’s a pleasure. It’s all full circle, and all here for the love of horticulture.
Ping Yu: Yeah. And I still remember vividly, when I was a grad student at Texas A&M, attending the plant physiology class when you were lecturing, and two of your PhD students are actually very close friends of mine. It’s exciting and magical how we kind of circle back [laughs] working for the same department. But as you mentioned, you grew up in Italy, what first sparked your interest in horticulture? Do you see yourself as a nature kid when you grew up, or how did this come onto your radar and become one of your interests? Or did you kind of stumble into this trajectory?
Leo Lombardini: Yes. I grew up in the city, in Florence, so I did not come from a family that was involved in agriculture. But I attribute my interest as a young kid to the fact that my parents bought a very old farmhouse in Tuscany in the late sixties and fixed it up. And one of the things that they did was actually resurrect an abandoned vineyard and olive trees.
So with a lot of sweat and hard work, and help from family, extended family, to have pruning days or harvest days, they were able to resurrect this vineyard, and they would start making wine, learning from scratch by asking around and trial and error. And I was there as a little kid, helping harvest, and seeing how the grape juice turned into wine. And of course, I would not try, well, maybe I did, but [laughs] we don’t have to say.
And also spending a lot of weekends and summers in this house, which is still in the family, actually, extended family. My cousins own it now. But the summers were days of finding ways to stay engaged and stay busy. This was pre-video games, pre-computers. So I had to find things to entertain myself, and they had to do with nature, whether it was planting trees or playing with the chickens. And I think that’s really what triggered the interest in plants, and to observe them grow and develop and give fruits and vegetables and all that.
Ping Yu: Yeah. And does your family who still own the property, do they still grow grapes and make wine?
Leo Lombardini: Yes, they still do.
Ping Yu: Wow. How many years?
Leo Lombardini: It’s been since the seventies, since the very early seventies.
Ping Yu: So it’s becoming a family tradition, the legacy that carried on.
Leo Lombardini: That’s right.
A Favorite Among Many Plants: Pecan and the Chestnut
Ping Yu: So I know that you have worked with so many different plants yourself, coffee included, and pecan, and now you’re a department head overseeing all those horticulture crops. Among all those plants, do you have a favorite, and why?
Leo Lombardini: Yeah, I really like, actually, pecan is a very interesting species that I became very attached to, not only because I studied it for a good 15 years, but also because it’s one of those plants whose history of cultivation actually precedes the arrival of the Europeans. This is a species that is native to the North American continent, and it had a very, very important role for Native Americans, because it was a good source of food, especially during winter months. The nuts were harvested and stored, and a lot of things were made with these nuts, which are very high in fat. So they were a very important source of energy and food for Native Americans.
And so I like that this majestic tree, that is really a beautiful tree also, had such an importance for Native Americans, but also for animals. Think about how much energy it provides to squirrels and birds and crows and others, because it helps them sustain throughout the winter. So I really like that.
And I kind of compare that to the chestnut tree. Chestnut is a very important species in Europe, at least the European chestnut, I’m talking about. And that’s because, just like the pecan, it is still harvested from the wild, especially during periods of hardship. I’m thinking about, let’s say, World War I, or other periods during the centuries, during pandemics, and I’m referring to prior to the COVID pandemic. It was essential to sustain families that were living in the mountains, places where there were not many other food sources during winter. So I compare the chestnut to the pecan tree because of this commercial, but also more social, importance for people and animals.
Ping Yu: Yeah. And I have to mention that the economic value of both of those is pretty important, because pecan has a pretty big role in Texas, and you spent years studying pecan back at Texas A&M.
Leo Lombardini: Yes.
Ping Yu: And here in Georgia, the pecan commodity is contributing a lot economically to our Georgia economy in general.
Leo Lombardini: Absolutely. Yes.
Ping Yu: So I see the reason behind why you love those.
How Leo Got Into Coffee Research
Ping Yu: [laughs] And I know you personally are a big fan of coffee, and you have done a lot of work on coffee, you were the director of the Borlaug Center for World Coffee back in Texas. People out there listening to this, I would say 90%, if not more, are coffee drinkers. [laughs] It’s such a beloved crop on the planet. But how did you first get involved in coffee research?
Leo Lombardini: Yes. It was one of those things of being in the right place at the right time, I guess. I have to give credit to Dr. Elsa Murano, who was and still is the director of the Norman Borlaug Institute for International Agriculture at Texas A&M University, because I interacted with her professionally in a few instances. At some point, the Borlaug Institute was awarded a fairly large grant from USAID, the United States Agency for International Development, which is now semi-defunct.
This was in 2014, when Central American coffee-producing countries had just witnessed a resurgence in coffee leaf rust, which is probably the worst disease that can affect the coffee crop. In 2012 and 2013, there was one of those perfect storms that had to do with climate, the developing of new strains of fungi, and then economic factors. Anyway, so this fungus became a serious concern for many of these countries. And so the Borlaug Institute, together with World Coffee Research and several of the big coffee players in the United States, joined forces, and this grant was awarded with the idea of helping nine Central American coffee-producing countries fight this disease and develop a more resilient industry.
So at that point, they were looking for somebody at the Texas A&M campus to help co-lead this project, especially for the component that was going to take place at Texas A&M, because obviously most of the activities were going to take place in the producing countries. And so this is when she approached me. She wanted to know if I was interested. And the reason she came to me, I assume, I hope [laughs], is because she trusted I could do the job, but also because I had previous experience working in Central America. I was quite fluent in Spanish. And so she asked me, and I immediately accepted, because I thought it was a very good cause and something I was very interested in.
And, you know, I just want to put a little parenthesis here, because some people may wonder: why is the United States interested in doing a project on a crop that is only marginally grown in the United States? Because, honestly, only Hawaii, Hawaii, and a very little bit of boutique coffee production in California, these are the only two states where coffee is grown in the United States. So why is the United States investing money in helping coffee-producing countries in Central America?
Well, there are at least a couple of good reasons. One is because we import pretty much all the coffee that we drink, and much of this coffee comes from Central American countries. So obviously it’s important for us to make sure that coffee importers and coffee companies continue to have their supply. But also, according to statistics, there are over two million jobs in the United States that revolve around coffee. That includes all the importers, but also think about all the coffee shops, the coffee roasters, all the manufacturers for the cups and the lids and the stirrers and everything else. And so it’s a good reason, we want to make sure those jobs are secured.
In fact, going back to the origin of this grant: when, in 2012 and 2013, this big coffee leaf rust outbreak took place, there was a spike in migration to the United States that economists and people who study this actually directly correlated with the coffee rust. So it’s kind of a soft approach to reduce illegal migration, and also being involved in illegal activities in some of the Central American countries.
Ping Yu: And some people may never have thought of science at this level. They would think, okay, horticulture is just horticulture. It’s plants, everywhere. But I’m glad that you mentioned it, it’s a very good example to show the impact of horticulture. We’re not just people growing plants; we help people in so many different ways, and not just in the United States, but worldwide. People rely on those activities to have a good life, and that’s our whole point as scientists, as universities, to provide all the resources to help them maintain a decent life so that they can be happy. That’s one of our goals.
How Studying Coffee Changed the Way He Drinks It
Ping Yu: So before we get scientific, let’s go back to daily coffee-drinking type of activities. When you take your coffee, because you have all this experience and knowledge on coffee itself, does it change the way that you drink it, from your daily routine of coffee drinking?
Leo Lombardini: [chuckles] Yes, certainly. It taught me a lot, also because when I started attending conferences that are focused on coffee, you are surrounded by real coffee connoisseurs. I remember going to one of the first meetings at the Specialty Coffee Association conference. You’re in this meeting because obviously you go to a conference not just to go to the trade show or attend presentations, but also to take advantage of having all these people at the same place at the same time to have meetings. So we would go to this conference and have several meetings with coffee company executives or other researchers, and literally in the middle of the meeting, you see these people opening their bag and they start to take out their coffee grinder, and they plug in their kettle in the wall.
[chuckles] So they start heating up their water, and they literally start preparing their coffee right there in the meeting. So you definitely start thinking about, okay, maybe [chuckles] I should revisit the way I drink my coffee. Indeed, you become, first, you really start appreciating high-quality coffee, because 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. And this is done, again, routinely by these coffee buyers and coffee experts when they evaluate specific lots of coffee.
So once you get used to it, you taste the good coffee, then you’re kind of hooked, to say, “Okay, I do see a difference between the regular store-brand pre-ground coffee and something that’s high-quality specialty coffee that is ground right before brewing.” And then you appreciate it, and you become a little bit more refined. So, long answer to your question, I have learned how to drink better coffee.
Ping Yu: [laughs] Well, the reason I ask you is because, I apparently didn’t directly associate with any of the research you have done, but I happen to be the roommate of one of your beloved PhD students, Sarah. We lived together for three years back at Texas A&M, and she has a specific way to drink coffee, and I kind of observed that. Because before, I drank instant coffee, those pre-ground coffees, and the quality of that is not comparable to better coffee beans. So I kind of had to add a lot of sugar and milk to make it tasteable. But after that, I started to get some sense of appreciating better coffee beans and coffees. And now, for all the coffee that I drink, at least at home, I don’t need to add any sugar. And sometimes now I just add a little bit of milk just to do the art that I like [laughs],
Leo Lombardini: Interesting.
Ping Yu:: I do like the latte art.
Leo Lombardini: Nice.
Ping Yu: Just for fun. But it definitely changed the way that I look at coffee myself.
Where Coffee Comes From: Species and Geography
Ping Yu: So, with coffee, it all comes from the coffee plant, and you briefly mentioned some of the big players worldwide that produce coffee. Can you show us the big picture of where those coffee plants and that coffee are produced worldwide, starting from the coffee plant itself?
Leo Lombardini: Yes. So most of the coffee comes from Coffea arabica. The majority of the coffee we drink, certainly specialty coffee, comes from the Coffea arabica species, which is one of 133 species in the Coffea genus. So, 133; most of them are actually from the African continent. They’re all native to Africa. But one important place for Coffea species is Madagascar. Madagascar has 67 of the 133 species of coffee.
Now, I talk about these 133 species, but the ones that are cultivated, actually it’s only about three, really. So there’s Coffea arabica, which supplies about 65% of the coffee that is consumed in the world. Coffea canephora, which is known as Robusta, which is pretty much the remaining 35%. And then there’s a third one, Coffea liberica, which is really less than 1%, and it’s only consumed locally. There’s not a market for it.
The reason Arabica is the most common one is definitely because of the quality, it’s the mildest of all the Coffea. The others have either a higher content of caffeine, which you think, oh, great, I get a bigger boost, but [laughs] it’s also associated with bitterness. The higher content of caffeine doesn’t necessarily translate into a better cup quality.
So, you asked me where they come from. As I mentioned, Coffea is pretty much the African continent. Obviously, Coffea arabica is from what is now Ethiopia, that’s where it came from. So, sometimes, especially for people who are not familiar with coffee production, you think about, oh, Colombian coffee, or Guatemalan coffee, Brazilian coffee. But if you think about it, none of these countries actually had coffee to begin with. It was all introduced between the late 1700s and mid-1800s as an additional source of income. Because once they realized that coffee was actually growing well, they started replacing existing crops, or maybe cutting down forests, unfortunately, to grow coffee.
And still today, Brazil is the largest coffee producer in the world. It produces about one-third, if I’m not wrong, I don’t have the numbers, but maybe even more, actually. Second to Brazil is actually Vietnam, the second-largest producer of coffee, but mainly Robusta, so Coffea canephora. So we usually don’t drink Vietnamese coffee, because it’s used to produce Robusta. And Coffea canephora is almost never drunk as a pure coffee, but it is blended with the Arabica for kind of inferior blends, or espresso blends, and things like that.
Ping Yu: Are you saying that if people want to get a taste of better coffee, if they go to a grocery store, they just need to look for Ethiopian coffee beans, instead of,
Leo Lombardini: It doesn’t have to be necessarily coming from Ethiopia. Ethiopian coffee is definitely high quality most of the time. Coffee is a major contributor to Ethiopia’s economy, a huge component of their GDP, because they export literally millions of pounds every year. And it’s definitely high quality. But you can get very high-quality coffee from Central America, for example. So, Colombia and Panama, Guatemala, Costa Rica, just to name a few. Honduras, El Salvador. [laughs] I have to be careful, ‘cause I have so many colleagues and friends from all those countries. I don’t want to forget their countries.
Ping Yu: As you’re naming those countries, I’m like, I will not forget, Nicaragua.
Leo Lombardini: [laughs] Mexico.
Ping Yu: Yeah.
What Coffee Plants Need to Grow
Ping Yu: So, basically, coffee as a plant grows mainly in those tropical areas where they provide the environmental conditions for them to survive. But when we talk about that, what kind of environmental conditions does the coffee plant really need to survive, and do those environmental conditions play a role in determining the quality of the coffee down the road?
Leo Lombardini: Yes, that’s a very good question, and you are correct. Obviously, just like all plants, there are some conditions that are ideal for a particular species to thrive. In this case, I’m just going to focus on the two, Coffea arabica and Coffea canephora. The two species are quite different in terms of their ecological preferences and growing conditions.
Because Coffea arabica evolved, or came from, the western highlands of Ethiopia, which is mountainous, you know, a cloud forest type of environment. So definitely higher altitude, frequent cloudy days, and never too hot. These are the conditions where the Arabica coffee thrives. So, temperatures, let’s say, averaging between 70 and 80 degrees, undercover, because this is a shade plant that evolved under the cover of larger trees in the forest. So this is why shade-grown, mountain-grown Arabica coffee is really where you can get the highest quality. Even though it might be the same identical species genetically, or clonally propagated, it would develop a different coffee and a different chemical structure of the fruits, the seeds, actually. Because maybe not everybody knows that the coffee bean is actually the seed of the plant,
Ping Yu: Yes.
Leo Lombardini:: which, of course, turns into the quality of the brewed coffee. In the case of Coffea canephora, Robusta, actually, Robusta comes from a much, much larger geographical region, which is pretty much all equatorial Africa. So you find native Robusta plants all the way from West Africa, but again, all equatorial. So, but typically in lowlands, not in the mountains like Arabica. So that’s the reason why the Robusta species, the canephora species, can tolerate higher temperatures.
But also, one of the reasons why it’s a lot more resistant to pests and diseases than the Arabica is because it comes from a much larger geographical region, where you can find different ecotypes, or plants that have been exposed to diseases and insects. It’s a much broader genetic pool than the Arabica, which only comes from a very, very small region, so there’s also a kind of inbreeding that had to do with it. So a lot of the current, modern varieties that we have have a little bit of Robusta genes in it, because of hybridization that has helped increase resistance in the Arabica to diseases and pests.
Seeing the Coffee Plant in Flower
Ping Yu: Yeah. And I would assume that folks out there who drink coffee every day may not have the privilege, like me, of actually seeing a coffee plant in the house. Because I was able to see the coffee plant producing flowers, and I was quite surprised to see how tiny the little white flowers were, scattered around the plant. Again, the coffee plant is a tropical plant, so you can imagine the leaves are pretty big and glossy. And compared to the glossy, showy leaves, those tiny little flowers are pretty small. But then I was looking at them like, “Oh my gosh, all those little tiny flowers turn into the coffee beans that we consume so much around the world.” It just surprised me.
And I know that botanic gardens, at least Atlanta Botanical Garden, in the tropical room or the greenhouse, have one or two coffee plants for people to look at. So next time, if you go there, check them out, and then it’ll probably change your perception of drinking coffee next morning.
From Plant to Cup: Harvest and Processing
Ping Yu: [laughs] So we’ve talked about a lot of the coffee plant itself, but can you give us an overview, walk us through how the coffee goes from the coffee plant all the way to being in the cup? Can you just walk through the whole process?
Leo Lombardini: Yes. I’ll have to be quick, ‘cause obviously there are several steps that take place from the field to the cup. Let’s start just a little bit before harvest. I just want to give a brief introduction on how the coffee plant grows. It’s considered a shrub or a small-sized tree. And it takes about between two and three years for the plants to develop the first flowers that you just mentioned. And then it continues producing for several years, 15, 20, 30. But obviously, for commercial purposes, at some point you either need to prune it back, so that the plant doesn’t become too big, which will become very difficult to harvest, but also to kind of rejuvenate a lot of the tissues. So there are several growers that cut it pretty much to the stump, at the stump level, and let it regrow and kind of rejuvenate.
Ping Yu: I wish we could do the same, too. [laughs] We could just cut a limb and then get new, younger, stronger,
Leo Lombardini: [laughs] But anyway,
Ping Yu: Cut, cut our hair.
Leo Lombardini: Right. [laughs] So, after coffee is harvested, it is a very delicate process. Because, for those who are listening who have never seen a coffee fruit, it’s very similar to a cherry. In fact, we also talk about coffee cherry. So you have the seeds, which in the case of coffee, unlike a cherry, the cherry only has one seed, one pit, but the coffee plant has two. So there are two seeds facing each other, and that’s why, when you look at a coffee bean, one side is flat and one side is curved, because the two flat sides face each other. So they have two seeds next to each other, and then everything is surrounded by a pulp.
And this process has to be done immediately after harvest. So you have to find ways to process the seeds very quickly. Because otherwise, this pulp, you have a plant tissue that is rich in sugar, very watery, and if you let it sit there, especially after it’s been bruised because of harvesting, it starts rotting and fermenting, which would obviously be disastrous for the quality of the coffee. So it has to be processed immediately.
And without getting into too many details, this can be done in at least three main ways. One: you take the fruits, you harvest the fruit with the pulp, and you immediately put them on a… usually it’s done on concrete patios, in the sun, to let it dry. And in this way, it has to be a pretty thin layer, about a couple inches, maybe less, so that all the coffee fruits start drying. And this is a process that can take two, three weeks, depending on the weather. So the pulp, the fleshy part, starts drying out, and it dries on the seeds. And this confers particular flavor characteristics to the coffee that will be brewed after that. This is called natural processing. And it’s typical in those countries where they don’t have a lot of access to water. For example, Yemen is a big producer of coffee, or even other African countries. So the coffee fruits are laid either on raised beds or concrete patios, where they dry.
The other process, which is called honey-processed, what they do, they immediately run the coffee fruit through a depulper that removes the pulp and separates the pulp from the seeds. And then the seeds, which are covered by a mucilage, which is actually a pectin, just like the one that we use for canning, making jams, then it’s laid in the sun to dry. This is called honey processing.
And then the third process, which is definitely the most common one, is called washed coffee. So the pulp is immediately removed from the seeds, and then the seeds, with the mucilage on top, actually get placed in tanks where they’re covered with water. And so they actually soak in water for a period between 24 and 48 hours, and they undergo a fermentation process in which the yeasts that are present naturally, in some cases they are actually added on the fruit, they break down this mucilage. And by doing this, when the seeds are underwater, they also transform the chemistry of the beans.
So after whatever process you do, at some point, obviously, the seeds have to be dried to about 10 to 12%, to make sure that the seed is no longer viable. It’s dead, so it doesn’t germinate, but also to prevent spoilage. So there’s an additional drying, which is done either on the patios and under the sun, or in a dryer with heaters. And then at that point, the coffee is ready to be bagged and shipped.
Now, for the coffee that was processed naturally, the one that still had the dry pulp attached, now there’s another step: this dried pulp has to be removed. So there are machines to remove the dry skin and then remove the parchment, so that they can also be bagged and then shipped. So in a nutshell, all this is happening in the producing country, as close as possible to the farms, because as I said, this post-harvest process has to be started as soon as possible.
Now, after the seeds, the coffee beans, at this point we can call them coffee beans, are in the 60-kilo bag, they can be stored locally, but also they can be shipped on the shipping containers all over the world. They can reach their destination, whether it’s Norway or whatever, on these big ships that can take it all over the world. So it’s a lot of work, and this is just to get to the destination. Because once it gets to the destination, then it’s stored again in warehouses. And at that point, it’s distributed to the roasters. Because coffee is shipped when it’s still green, not green meaning, you know, like green beans; meaning they’re not roasted. They look kind of greenish, and they don’t taste, they don’t smell, anything like coffee. Actually, if you put a green coffee bean in your mouth, it’s very hard, first of all, but also it’s got a kind of grassy flavor. So only after roasting is when you start getting all the aroma and the flavor characteristics that are typical of coffee.
Ping Yu: So, and then of course, after it’s roasted, and when you were describing the post-harvest process of how coffee is being treated, I wanted to rephrase the processing in a different way, where people would vividly, visually imagine the whole process. Here’s what I was thinking while you were describing it. I was thinking: there are three ways for coffee to be produced after harvest. And so those are the three ways of producing coffee, and then after that, it’s all packed and shipped to the destination, for people to start roasting it.
The Art of Roasting
Ping Yu: But in terms of roast, I know there are three main ways of roasting.
Leo Lombardini: Not really. I mean, the roasting is pretty much one procedure. You have this big roaster. Many of them are drum roasters, which is, imagine a dryer, like the one that you have at the house for clothes. It’s the same concept. You have a source of heat, which is either generated by gas or electricity, and the main difference with the clothes dryer is that the temperature [laughs] is a lot higher. It gets to about 400 degrees Fahrenheit for coffee.
And so, once the green coffee beans are dumped in the roaster, the head roaster can play with two variables: temperature and time. So you can have a lower temperature, and you keep the beans longer in the dryer. And when I say longer, we’re talking about between, let’s say, 18 and 20, 21, 22 minutes. So each cycle is about that long. So you keep the temperature a little bit lower, but high enough that you still have a roasting process. You don’t want to have a temperature, let’s say, of 300 degrees, because you would just barely bake it, it wouldn’t trigger the chemical transformation. So, or you can decide to have a higher temperature for a shorter period of time.
It should really be: how do you like your coffee roasted? Any coffee shop, any coffee roaster would have a target roasting level, which is based on their preference, based on their customers, based on what they’re trying to do. For a large roaster, the largest roaster in the world is probably Starbucks, because they source their coffee from so many different farms around the world, from different varieties. What do they do to make sure that if you go to a coffee shop and you order, let’s say, a Verona blend, it always tastes like a Verona blend? What they do, they tend to over-roast a little bit. So that’s really the reason why, if you go to a Starbucks, their coffee is always kind of over-roasted, kind of a charry, burnt. Because by doing this, that’s the only way they can put all these different varieties and different origins together and make sure that the Verona blend always tastes pretty much like the Verona blend.
But a small coffee shop can afford to roast, like, a medium roast, which is considered ideal to really savor the quality. Because they use smaller, they source it from smaller farms. Or if one year they say, “We don’t have this blend,” because that farm had a disease outbreak or whatever, they can always replace it with another one, and just inform their customers. So there are all those business decisions that really drive roasting. But, yeah, as I say, it’s a fairly simple process. The operator, or the roaster, or the owner decides how they want to roast their coffee, based on their preference and their customers’ preference.
Ping Yu: But what is the difference between, let’s say, light, medium, and dark roasted coffee?
Leo Lombardini: It’s a combination of time, the time that those beans stay in the roaster, and the temperature.
Ping Yu: So what would that lead to in the taste of the coffee?
Leo Lombardini: Oh, it definitely changes. And of course, there’s been research done, but the one thing that does not change is the caffeine content. Caffeine is actually present in the beans already when they’re green. Because, why does the coffee plant, and others… Caffeine is not only produced by the coffee plant, but there are others. Caffeine is an alkaloid that is used as a natural deterrent against pests and diseases. So that’s present in the plant to begin with, and it’s present in the leaves, but mostly in the seeds. Because, what is the purpose of every living organism on this planet? To reproduce. So obviously it’s in the plant’s interest to pack those seeds with caffeine, so they will less likely be attacked by insects and diseases.
So you have this caffeine that’s in the bean. It’s about 1 to 1.5% of the dry content of a coffee bean, so it’s significant. So that caffeine content does not change during roasting, luckily for us, because caffeine is pretty stable at high temperature. But what changes is, for example, the level of acidity. Acidity is actually a good trait for coffee. The best-quality coffees are the ones that have a high acidity, which is counterintuitive. It’s like, wait a minute, if you think about, let’s say, orange juice or lemon juice, the more acid it is, the more bitter it might be. But for coffees, it’s the opposite.
So the longer you keep those beans in the roaster, the lower the acidity of the brewed coffee will become. So that also tells you that the quality of the brewed coffee is going to be inferior. For coffees that are roasted, let’s say, a French roast, or even an Italian roast, which is the extreme, really, before it burns. [laughs] So for light to medium coffee is really when you can savor all the properties that are in that cup. So that’s the one that is recommended if you’re really trying to assess the quality of a coffee.
Ping Yu: So basically, the acidity does not have something to do with the time. It’s more related to the degree of roasting. Okay.
Leo Lombardini: Yeah, the degree, which again could be… you can have a dark-roasted or French-roasted coffee bean by increasing the temperature, keeping it high for a shorter period of time, or reducing a little bit, keeping it… Imagine baking a cake. You could bake a cake, instead of, if the recipe says 20 minutes at 400 degrees, you could say, well, I could put it at 480 and keep it for 10.
Ping Yu: Mm-hmm.
Leo Lombardini: Or you could keep it at 350 for 30 minutes. But are the three cakes going to be the same? Probably not. Because if you do it at 480 for 10 minutes, most likely the outside is going to be burnt, but the inside is not. And maybe the opposite is going to be for the one that you keep the longest, it might be too dry. So that’s really a lot of playing.
And what roasters do, when they get a new batch of coffee, maybe a variety they had never used before, or maybe a farm that they haven’t bought from before, what they do, they just do a little scientific experiment. They take a batch and they roast it. And of course, they would not use the big roaster to play with. There are small roasters, like a benchtop that only does, let’s say, 200 grams, 300 grams, or even less, and you play with it. You play with all this, and then at the end, you sample, you try the cup, and you say, “Okay, that’s the one I want.” So at that point, you develop your recipe, and you transfer it to the big roaster.
What Every Coffee Drinker Should Remember
Ping Yu: So for listeners who have listened to this episode, what kind of message do you want to give to the listeners who are daily coffee drinkers? Let’s say they’re going to drink coffee tomorrow, what should they remember about coffee?
Leo Lombardini: One thing that I could probably recommend is: next time you buy a coffee in a bag, look at the package. And before you buy one, just try to educate yourself. First, does it say 100% Arabica?, which already tells you something. Because there are a lot of coffees out there that don’t say. They just say 100% coffee. If they say 100% coffee, that means there’s some Robusta in it. So that’s definitely going to change it.
Also, see if it specifies the country where the coffee’s from. So maybe next time you can compare two different countries. But of course, you cannot really compare two countries, ’cause for example, you could get from the store a medium roast Ethiopian, and then you have a dark roast Guatemalan. So when you compare them, do you really compare the country, or do you compare the roast level?
Ping Yu: Yeah. [laughs] So it’s kind of like an experiment.
Leo Lombardini: [laughs] Yeah, exactly. You understand very well. You’re obviously a scientist. So, but first of all, again, educate yourself. But also, if you go to a coffee shop that is not like a large chain, try to see if the barista knows a little bit about coffee. Ask questions, “Do you have different origins? Do you have different…” And unfortunately, in most cases, the employees are just, I don’t want to say students, because they’re students that are very educated, but maybe they just need a job. So they might not know. But it might actually trigger their curiosity, and next time they see their supervisor, maybe they’ll ask. They say, “Oh, a customer asked me, where do we get our coffees? What can you tell me more about it?”
So, again, educate. 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, whether it’s a steak or an orange, that has spent a lot of time in the field, really taking time away from their family, from watching TV or whatever, just because they’re very passionate about what they do. And let’s never forget that we should always remember our farmers and support them.
Ping Yu: Yeah. And all of that, again, is the same concept, the information that I keep sending out repeatedly. Just appreciate what you have, because everything that you see daily, day in and day out, is tons of work from other people, especially in the horticulture world.
The Future of UGA Horticulture
Ping Yu: And I know Leo is a great researcher himself, but in addition to that, he’s also a very good boss and a great department head. Since you joined UGA, you have developed and initiated many wonderful programs and activities. But what is your next excitement with your role at UGA?
Leo Lombardini: Ooh. [laughs] Well, first of all, thank you. I’m glad that you think I’m a good supervisor, administrator. Hopefully this is not just for the show.
Ping Yu: [laughs] No, no, no, you are.
Leo Lombardini: Thank you. I think our department is in a very good state right now. I’m proud to say that in six years, we added 18 new faculty members, including you, which bring a lot of energy, a lot of new ideas. There’s nothing better than, as a supervisor, to surround yourself with people that are smarter and better than you, because they make you look good. [laughs] So if you all are doing well and are successful, it’s very easy for me to brag about the department and go to my supervisor when I have to provide reports and everything else, because you guys make me look good.
So that’s really, at this point, my goal, to make sure that everybody has access to the resources that they need, at least. Obviously, we all would like to have maybe a better lab, or a larger greenhouse, or new vehicles. We cannot do it all, but at least have enough that we can sustain high-quality programs and really help Georgia growers, and even outside of Georgia, the state, the country, and internationally.
So that’s really all. And also, I think we all have a mission, all of us in horticulture, to make sure we continue to promote horticulture as a discipline. Because many of our students, I am talking about undergraduate students, they don’t discover us until they’re already at the university, and they stumble upon a class or a roommate. They describe what horticulture is, and then they come to us, and they love it, and they never leave once they come with us. Because that’s really, “My gosh, this is exactly what I wanted to do.” And it’s so therapeutic working with plants. So that’s really what we’re going to continue doing, make sure that we advocate for our industry and our discipline.
Ping Yu: Yeah. I think that’s one of the reasons, one of the missions, for the podcast and a lot of other activities. We want to deliver the message to a larger audience, to the public, say, horticulture is a thing, and it’s a fun thing. So people need to take a serious look at us, and hopefully we lure more future horticulturists to our world.
Where to Learn More
Ping Yu: So with that in mind, if people want to find out more about horticulture in general, and/or follow up on some of the work that you have done in the past or in the future, where do you recommend they go and look?
Leo Lombardini: Yeah, certainly. Obviously, our website is the easiest way to learn more about our department, and all the faculty, including you, and what they’re doing. They can Google “horticulture UGA,” or go to hort.caes.uga.edu. Over there, they can find links to all the faculty profiles, our academic programs. And, I also have a, you know, we try to put out a newsletter at least a couple times a year. So all those that are connected to UGA can get a copy of that. It’s obviously electronic.
Ping Yu: And I’ll put all the links out there in the show notes, so people can find the information easily. I can also put your profile there, if they want to have direct contact with you about potential opportunities down the road. But thank you, Leo, for taking time out of your busy schedule to talk with us and educate us on coffee, and to show us all those wonderful things going on within UGA. I really appreciate that.
Leo Lombardini: Thank you. Thank you for the opportunity. It’s been a pleasure.
Closing and Credits
Ping Yu: Conversation like this only happens when you support the show. For more information and to find ways to support us, please go to bandbpod.com, bandbpod.com. If you like what you are hearing, spread the word and share this podcast with the people you love. Make sure you hit that subscription button and give a review for the podcast. And as always, go check out the show notes to learn more about this topic and other topics we feature on the show, at bandbpod.com. Thank you for listening. Till the next time, stay healthy and go plants.
Transcript produced for Blooms and Beyond / UGA Center for Urban Agriculture