#18: Anaerobic Fermentation: Building Our Coffee Vocabulary

[Music] Welcome to Making Coffee, a behind-the-scenes look at what goes into making one of the world's favorite beverages. I'm your host, Lucia Solis, a former wine maker, turned coffee processing specialist. Thanks for joining this week's episode. Hello friends, and welcome back to Episode 18. I say welcome back, because today's episode builds on some concepts from Episode 4, which talks about over fermentation, and then also Episode 15, which talks about how the sugar and coffee fruit becomes a flavor in your cup. So if today's topics feel kind of unfamiliar, then I would recommend you going back and listening to those episodes as well. So today's episode is inspired by a patron of the podcast. His name is Joaquim, and he runs a small coffee bar in Georgetown, Penang, Malaysia. I've never worked in Malaysia, but I hope to get a chance to work there, because the internet tells me that Georgetown is the food capital of Malaysia, and experiencing a culture's food in its native setting is basically my favorite hobby. Here is Joaquim's question. Hi Lucia. We recently got quite a number of anaerobic or double anaerobic coffees, which were meant for competition, and we were tasting them. We are aware that anaerobic doesn't really mean anything since all fermentation is anaerobic, but is it just a marketing gimmick, or, at the best case, does it set a range of expectations of flavors? Appreciate your thoughts on this. Okay, so let's jump right into today's topic, anaerobic fermentation. I'll admit, these are not the typical topics for a coffee podcast. In fact, if you're a coffee drinker, there's a good chance you haven't heard this term yet, but if you stick around specialty coffee a little bit longer, I'm sure you'll see it pop up on a coffee label or a website or social media. And when you see it, I want to help you feel informed instead of confused or intimidated. Admittedly, this episode is a deep dive into a niche corner, microbiology of processing, of an already niche industry, specialty coffee. Not only are we talking about a highly specific term, but it's also a recent application of that term. So we're treading on new ground into dimensions. Specialty coffee is a young industry compared to the wine industry or even craft beer. In the consumer space, we have only recently started to differentiate between processing styles like natural, washed, and honey, and now we're jumping off the deep end and into the microbiology of these processing styles. It's like last week we were crawling, and then yesterday we finally kind of stood up, and we were able to be comfortably upright, and so now we think we're ready to run full speed downhill. It's been official to remember that the specialty coffee industry is in its infancy, and it's because of this infancy that I believe it's a good time to talk about this. As we speak, the foundations are being established. New people are hearing about it for the first time. And if we don't start off with a solid foundation, the structure upon which we build everything else will be unstable. And it's not too late to self-correct. It's not just Joaquim, I frequently hear from many that are confused all along the supply chain. Very few of us currently feel comfortable using these terms to describe coffee, and yet more and more of us are using them. Green buyers ask me what producers mean when they label their coffee like this, and producers ask me what green buyers mean when they ask them for an anaerobic process. Both parties expect that the other one has the answers, and both are hesitant to ask for clarification. And even if the words are poorly understood, they are still copied and pasted and repeated, and this happens so much that they become familiar through sheer repetition. We see them so much that we can sometimes convince ourselves that we know what everyone is talking about, or we assume that at least they must know what they're talking about. But in my observations, it seems like at this point everyone has their individual, personal, and unscientific definition. And this is a problem because when everyone defines the words differently, we undermine the point of language to communicate. Hence the confusion, and people writing to me asking me to sort it out, asking my opinion on who's doing it right and who's doing it wrong. But I'm not here to patch judgment, or to decide who is right or wrong. I'm here to share with you some microbiological facts along with some personal opinions, and then you can decide what to do with them. This episode is most relevant to coffee producers who use these methods in their mill. And I know not all of you listening are producers or exporters, maybe you're not even buyers or roasters or baristas, but please don't skip this episode. Hang in with me a little bit longer. Because as we are being constantly reminded during this pandemic, we are all more connected than we think. What happens over there does it nicely stay over there. So even if you're a coffee enthusiast, or just a casual consumer who thinks this has nothing to do with you, please reconsider. I think we should all care about the microbiology of coffee fermentation. If you're a producer, I want to help you control what's going on in your tank. If you're a buyer, I want you to deeply consider what you may be asking a producer when you're looking for unique protocols. And if you're a consumer of specialty coffee, I want you to be aware of the type of marketing you are rewarding with your hard earned money. To begin defining anaerobic fermentation, we first need a stronger foundation, a stronger foundation built with more words. I think we need more words in coffee. For example, even in that phrase, I think we need more words in coffee. Maybe you agree or disagree, but it would depend on what part of coffee I am talking about. For the sake of clarity, I would need to specify if I am referring to the coffee fruit, or the coffee tree, or coffee culture, or the coffee industry, or the coffee beverage. The word coffee is a huge umbrella term that covers many parts. And sometimes we are lazy and just say, in coffee, and everyone fills in their own blank depending on their background. In contrast, the physical culture refers to growing wine grapes. Eonology refers to the transforming of those grapes into wine, and then when we say the wine industry, we know we are usually not speaking about the other two. So having more words like this is useful because we're able to describe the different facets and reduce confusion. When grape juice is fermented into wine, we call that wine making. The wine is made once by a wine maker. If I said coffee maker, you probably picture a countertop machine, not a person. But when is the coffee made? If I said coffee making, I think it could apply to coffee plants being converted to exportable green coffee. Or it could also refer to turning those green seeds into roasted beans. Or it could apply to brewing those roasted beans into a drink. Coffee is made several times, but we have a single word to encompass all of these different facets. In fact, I took this vagueness to form my advantage for the title of this podcast. Making coffee works on the level of the beverage and the level of the transformation of the fruit. But it's not just a deficit in English. Let me give you my favorite example in Spanish. So the coffee fruit has three distinct botanical tissue layers, the exo-carp, which is the outer peel, and the pericarp, which consists of a thin layer of fruit pulp and a pectin layer, the musulage. And we can collectively call that the miso-carp. But in Spanish, you will hear all of these referred to as bulba. La bulba is a single term that includes all of these tissue layers. And yes, in Spanish, exo-carp, pericarp, and miso-carp are available in the vocabulary, but these are really botanical terms, and they're not frequently used, just the colonial bulba. And this isn't just a cultural quirk. Let me share with you why this is problematic. To process coffee, we must separate the layer. To remove the exo-carp, la bulba, you must also simultaneously expose the miso-carp, la bulba. So when the coffee fruit has its exo-carp removed, you say it was "de-polt". But on the flip side, what you are left with is the musulage-covered seed, so you call that "polped coffee". So, scientifically, I could say "I removed the cherries exo-carp to expose the miso-carp". Or "clogally", I could say "I depolped the coffee, I tossed the pulp, and now I'm left with pulped coffee". Because there is a shared word "pulpa" for two distinct parts of the cherry, when you remove one, you have to expose the other, so we linguistically create two opposite terms for the same thing. And "depolped" instead of being opposites, they point to the same process. So on one side, we have the single term "pulpa" that collapses three layers into a single word, and on the other side, there are two terms that describe the same thing. So we have a collapsing, and then a redundancy. This collapse can give us a clue that "how the tissues were removed" was not that important because all three got the same word. The subtle differences were ignored. But the fact that there are two terms that redundancy for the same process also gives us a clue that it was important to remove them. In culture, we generally have more names or words for things that are important. Consider how many words the inuit have for snow, because how we construct our language reflects our values. And sometimes you'll hear at Museo Lago instead of "pulpa". And it's more common now as we are paying attention to the fermentation, but traditionally, there was no need to distinguish between the tissue layers, so most people didn't. The way that coffee was processed was not tied to quality, so why would they waste time making up more words than was necessary? And this is why I feel like we're trying to rewrite history a little bit, because by valuing a certain kind of fermentation, a certain type of fermentation, for example anaerobic fermentation, then we can kind of fill in the gaps, perhaps creating a version of history where coffee fermentation is valued. But it's not. It hasn't been. The coffee producing industry didn't even bother to make enough words to describe it because it was so invisible. And now we have a situation where consumers are creating the words, imposing them, and then creating an alternate version of coffee history, a parallel universe. So with that foundation, let's move on to how we are trying to build on it. My issue with anaerobic is twofold. One is technical and one is philosophical. Let's start with the technical definition first. All you have to do is google fermentation, and you'll have the definition pop up. Fermentation is a metabolic process that produces chemical changes in organic substrates. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. Okay, so there's two important things from this Wikipedia definition. Fermentation is defined by the absence of oxygen, so it's in there. And I want to point out the wording of the definition, quote, "in biochemistry, it is narrowly defined." If we want to talk about biochemistry or microbiology, things have already been very narrowly defined, and I think we should respect that structure. I see a lot of casual uses for scientific terms. We are fast and loose with our application of labels, and it's confusing because in science, fermentation has a narrow definition. Specificity and narrowness are the cornerstones of science. But in coffee, it is used broadly, and that can also be valid. And it should evolve. It should evolve. Definitions change. We should have some room for growth. However, specialty coffee is such a young industry that I think we could benefit from following the rules a little bit longer before we go out and try to redefine terms. Because otherwise, what we are left with is this current state of confusion. Currently, many of us are not being clear that we are using scientific terms in completely non-scientific ways. The term anaerobic fermentation is confusing to me because it is redundant and non-scientific because it's already the definition of the word fermentation. It's already part of the definition, so adding the part anaerobic is more of a step backwards than forwards. But let's take another step backwards, because another part of my issue is the use of the word fermentation. I believe this word is frequently misused. So, backwards from the end product, backwards starting at the cup of coffee you can hold in your hands. Your coffee beverage was brewed with hot water to extract the flavor from ground coffee beans. Before the beans could be ground up, the whole beans first had to be roasted. Before they were roasted, they were dried green seeds. Before drying the seeds, they needed to be extracted from a fruit. The coffee fruit looks like a cherry, but it usually has two large seeds with very little flesh surrounding them and very thick skin. The thick skin and that layer of flesh are a barrier to getting the seeds that we want. The objective was to free the precious seeds that were trapped in that sticky fruit. I think historically a more accurate definition of this phasing coffee processing would be to call it rot. If you picked coffee and left it alone, it would get mushy and it would be easier to get the seeds out. This rotting step was a way to let nature solve the problem. I'm not sure when this step started to be called a fermentation, but that is how we talk about it today. I want to emphasize this point because I think it sets up a lot of the foundation of how we talk about coffee processing. Since 2007, when the National Health Institute undertook the project of mapping the human microbiome, we've been more aware of the culture of the importance of microbes that are in our gut and our environment. Colonarily, we are talking more than ever about probiotics and prebiotics and fermented foods are definitely in the zeitgeist. So we elevate coffee to the status of a fermented food, but we're overlooking the fact that traditionally the step was little more than a passive rotting. Originally, the coffee market was not set up to reward differentiated coffees. It was set up to reward volume and speed. As soon as it was discovered that you could skip the fermentation step and get your seeds out faster with machines, most of the industry who could afford it went in that direction. So I think that we often over romanticize this rotting phase by calling it fermentation. Because when we talk about fermentation in wine, it's a very active step. There is a huge amount of sanitization. There's selecting the strains of the microbes that will be active and a lot of effort in monitoring the tank, because the fermentation is essential to the transformation of the product of grape juice to wine. Fermentation is revered because it's essential for the product and it's tied to quality and identity. But in coffee, historically, it was a passive step, a non-action step. It was what happened when producers did nothing. So in those cases, I don't think the word fermentation should have been applied because using the scientific word to describe this process adds more intention and weight to the process. It is a word that elevates the process in our mind's eye because we lend coffee the idea that we have a fermentation in these other industries. So if your only objective is to remove the seed and have a neutral impact on flavor, I think we should call that something else to distinguish it from trying to remove the seeds while seeking an impact on flavor and quality. This is why, six years ago, I started a very unsuccessful campaign to replace the word fermentation with microbial demusolagination. I think I can count on one hand a number of people who have written to me to ask questions about microbial demusolagination and for those brief moments, I feel very seen. Because for me, this term more accurately described what's happening. When a producer doesn't intervene, the microbes found in the environment break down the musulage and within a few hours the seeds were less sticky and the remaining residue could be rinsed off and then the seeds are sent to dry. In this case, the microbes are not transforming the product. They are not the stars of the show selected for quality. They're just doing a very simple job of making the coffee less sticky. So because this is my podcast, this is the part where I'm going to put in my opinion. I believe that if it is a passive step and the goal is to get the seed out as quickly as possible, then this step in processing should be called microbial demusolagination. This is the counter term to when we use an eco-pulpour and water and friction to remove the musulage because that step is called a mechanical demusolagination. And that is because in both of those instances, the goal is to remove the musulage not to create flavor. In fact, many hope that that step is as neutral as possible. But if it's an active step and the environment is altered in order to select for certain microbes, I think that's when it's appropriate to be called a fermentation. I think the word fermentation should be reserved for an intentional process with the express goal of having an impact for the express goal of creating flavor. And I need to reinforce that this is my opinion because it's a confusing matter. Scientifically, when you leave coffee to rot, the microbes remove the musulage through their metabolic activity, which is technically a fermentation. And it's actually extra confusing because in the coffee industry, fermentation is a step of the process. It's a static thing. But it's also a metabolic activity, a dynamic process. So the same word is used for two very different and opposite concepts and it's used interchangeably. One process is alive and the other process is mechanical. It is used both as a noun, the step between pulping and drying, and a verb, the act of infusing flavor. So again, we see this theme of collapsing three distinct functions. So the first one is rot, microbial demusulagination, and fermentation, collapsing those into a single term. And then we see the same word fermentation used to describe a process with opposite meanings, where one is static and mechanical, and the other is dynamic and alive. So we have a collapsing and an expansion. So if we can at least begin to parse out when someone is using fermentation to mean the part where we get rid of the sticky stuff, and when they are using it to mean the part where we can add flavor and complexity to coffee through microbes, well, then I think we can go a long way towards untangling some of the confusion. Okay, that ends the tangent on fermentation. So let us get back to the confusing aspects of just anaerobic. So the other way that anaerobic fermentation is confusing is that when you label something, you open up the linguistic possibility of its opposite. If anaerobic fermentation is something, then its opposite, aerobic fermentation, must also be something, right? But in coffee, it's not. When the breakdown of glycolysis uses oxygen, it's called respiration. We humans use respiration. We break down glucose in the presence of oxygen and yield 36 ATP. That's 36 energy units. And microbes break down glucose to produce ATP, but they do it without the presence of oxygen, and they only produce 2 ATP. So it's a much less efficient system for energy, but that's the one that produces the flavors that we are interested in. I will mention that certain yeast can metabolize sugars in the presence of oxygen. So in this instance, you could call it an aerobic fermentation, but this is a modified cellular metabolism, most notably found in cancer cells. So this means that it's most common when things have gone wrong. If you look deep in the corners of science, you can find evidence for all kinds of exceptions. We are discovering new microbes all the time, and they have different metabolisms. So if you want to write to me about a specific microbe that has this metabolism, I'd love to know about it. But my point is, the kind of fermentation we are talking about when we talk about coffee flavor is a regular old anaerobic kind. It's a process that doesn't require oxygen, so we don't need to say that it's anaerobic because that's the definition of it. That's why it's redundant. For example, we don't need to describe water as wet, because that's an inherent property of water. So if you choose to describe a particular fermentation as anaerobic, you do have science on your side. You are technically correct, but you should also use it to describe the honey process and the natural that are drying on a patio. Because in an attempt to be more specific and describe something with seemingly more accuracy, we inadvertently do the opposite and advertise our ignorance. So it's not a helpful distinction. It doesn't address the heart of the matter. But what is the heart of the matter? Why are we tempted to name the fermentation in the first place? I think we do this because we are trying to use a word that describes what we noticed. We notice that when you put coffee in a different tank, the flavor of the coffee changes. We know that we get different flavor outcomes when we ferment coffee in a traditional open concrete tank versus a closed stainless steel tank. Whether the tank is open to the environment or protected and closed off clearly impacts the flavor. You don't need to be a scientist or even a coffee professional. Anyone can taste these two coffees and find a difference in flavor. So let's say you've gotten this far and you still want to label your fermentation to distinguish it. I suggest you use the term anoxic. This refers to the environment that the fermentation is happening in, not the type of fermentation. And while anoxic is more accurate, I still don't believe it's a satisfying solution. When we describe the environment, it's a step closer to narrowing down the responsible agents, but it could still be tens of thousands of microbes that are present in that anoxic environment. When we talk about over fermentation and double fermentation and lactic fermentation and acetic fermentation and aerobic fermentation, and even now maybe we'll start to see anoxic fermentation on coffee bags, labels and social media, I think that this is a mistake. Because we keep looking for language to modify the fermentation part, but that is the element that remains the same. So any attempt to embellish the fermentation, I think fundamentally puts us on the wrong track. We are not isolating the right elements. We are not describing the right difference. This reminds me of the Buddhist teaching. The finger pointing to the moon is not the moon. Meaning we need the finger to point and show us where to look, but we mustn't mistake the finger for the moon itself. Because if you stop to focus on the finger, then you will never keep going and see where the finger is pointing and you'll miss the truth of what we are looking for. Because the truth is, oxygen does matter, but not for the reasons that we think. It is the finger, not the moon. The oxygen does not change the type of fermentation. It changes the type of microbes that are present. For example, acetic acid bacteria are obligate aerobes, meaning they can only grow if oxygen is present. So by obligation they need air. There are the ones that create this fruity sometimes boozy quality found in natural or dry processed copies. If we exclude oxygen from the environment, the yeast and other bacteria that are also present can grow more easily. So it's not about the type of fermentation. And it's not exclusively about the environment. It's the identity of the yeast and bacteria that changes the flavor. And if it seems like I'm nitpicking, it's because I am. Remember, we're trying to get to the scientific narrow definition, not the cultural broad language that is open to interpretation. But this distinction is especially important to me, because when we don't credit the microbes for the flavor change, when we say it's the type of fermentation, that's when we can make the easy and counterproductive leap to equipment. So we just zoomed in real close to the level of yeast and bacteria. But before we leave this topic, let's zoom out again to the producer, to the farm, because I want to share with you what I see happening. So for example, say there's a flavor in the cup that we like. Maybe it's bright, it's as this like sparkling acidity, or maybe we tasted rose or bubble gum. And maybe you were told it was an anaerobic fermentation, and you probably assumed that it was made in an enclosed manner that avoided having oxygen. Or maybe you even dug a little bit deeper, and you saw that the coffee was made in a stainless steel tank with hoses sticking out. So now what happens is you've linked the two. You've linked the flavor with that equipment. And then we think that the equipment is responsible for that flavor. But the equipment is inert. It can't do that. Again, that's the finger, not the moon. It's not the equipment, but the microbes that thrive in the environment created by the equipment that result in that flavor. The identity of the microbes is the moon. So many producers see these pictures on social media, or are advised to get these tanks to achieve a particular flavor. And I think this is a problem because it's an investment of money that few producers have. But even if they did have the extra fun money to spend, it's still unnecessary. It's money that could be invested elsewhere. And I believe that even if it doesn't harm the producers who could afford to make this investment, it raises the bar on expectations and can exclude the producers who can't afford or have access to that equipment. It can lead some producers to believe that they will not be able to be specialty producers until they can purchase this equipment. But the truth is beer or wine tanks are terrible coffee tanks. I mean, a few things bum me out more than when I see a coffee producer who has fallen for this because it's so unnecessary. Many producers can achieve that flavor profile with few modifications of their existing equipment because we're talking about the identity of the microbes, not special tanks. And this is why I believe so strongly in the power of microbes to democratize quality. And this is why I despair when I see a picture of these tanks circulated on social media. It bumps me out so much when this is praised as innovation instead of seen as ignorance. So here is my public service announcement. Producers, please do not buy these tanks for your meal. Buyers, importers, exporters, please do not encourage producers to buy these tanks. And coffee drinkers, please do not be impressed by these tanks if you see them in a meal or on social media. For me, one of the goals of specialty coffee is to value processing. When consumers care about how their coffee is processed, it allows a producer to play a larger role than has been historically possible. A producer can now share the spotlight with the roaster. They can be peers and partners in quality. They can work together to co-create flavor. And this is how we can begin to shift the power imbalance. The point of caring about processing is to spread that power and democratize quality to make it more achievable, not less attainable. When we talk about processing in these terms, we are inadvertently reverting back to our colonial roots and re-commoditizing it. Because that's what I see happening when we try to improve coffee quality by encouraging a poorly understood process or recommend buying specific equipment for that process. This is how we end up further frustrating and disenfranchising the people we say we want to help. So if you're a producer, help educate your buyer when they ask you for an anaerobic fermentation. You are the authority on how you process your coffee. And if you're a buyer, consider not asking for a process like this, especially if it involves new equipment. But most importantly, consumers, think carefully when you buy a bag of coffee labeled this way, especially if there's very little other information. If the company is only describing the process as anaerobic but they're not telling you the name of the farm or the cultivar, consider not supporting the structure of buying coffee. It pretends to care about the origins of where this coffee came from and how it was made, but I think it's lazy and you're being swayed by glossy marketing tactics. In my opinion, calling out unique processing without referencing the people behind those processes is not an alignment. Because how can we value something that is anonymous? To change the pattern and respect coffee, we need to care about where it comes from, not just how it was fermented. So I'll wrap this up with a few descriptors that I do like and that I think are worth using. The first one is a dry fermentation. So this is when the pulped coffee is put into a tank exactly as it is. It won't be dry to the touch because it'll still have some juice from the fruit, but it just means that no additional water will be added to the tank. And the other one is a submerged fermentation. This is when the tank of pulped coffee has had water added to completely cover the coffee inside of it. And these two methods will yield very different flavors in the final cup, but the flavors will also depend on the length of time that the coffee was in the tank, the temperature as well as the coffee cultivar and the nutrition density of that plant. And of course, also how it was dried and how it's been stored. So I'm really happy when I can see a coffee bag label that includes time and temperature. For example, instead of just saying dry fermentation, they will say 24 hours dry fermentation at 30 degrees Celsius or perhaps 48 hours submerged fermentation at 19 degrees Celsius. And I'm barely able to catch my breath about how I'm not convinced that we should be using the word fermentation so liberally. And then we're piling anaerobic on top of that. And then I have Joaquim mentioning that he's already getting samples labeled double anaerobic fermentation. So you can imagine how I feel about that. But that's enough for today. Deep thanks to Joaquim for inspiring today's episode and thank you to the other 40 individuals who support this podcast through Patreon. It's through their generosity that I can make it available to you all. These episodes are not sponsored or supported through any advertisements. It is completely listener supported. If you would like to join this community of individuals who value coffee education, consider supporting this free podcast by visiting patreon.com/makingcoffee. You can help keep this information flowing to the wider community with the cost of a single cup of specialty coffee a month. Also, if you enjoy these episodes, please consider sharing with a friend. And if you want to be notified when the next one is coming out, consider subscribing to my free and infrequent newsletter at lucia.coffee. And Lucia is spelled L-U-X-I-A. Thanks for listening and remember, life's too short to drink bad coffee.