Coffee Day 4: Break Your Brain

I'm writing this after both weeks of classes ended, but I wanted to capture some of the moments and feelings I had from day 4 (the 2nd day of SCA Sensory Intermediate) because I feel like it was a turning point where I started to understand how to walk down the path to refining my senses of taste and smell. It's a bit all over the place with bits I learned all throughout both weeks and some info from the books Flavor: The Science of Our Most Neglected Sense by Bob Holmes and Sip'n' Slurp by Freda Yuan.

We can start off with some info about papillae because in my last post I promised I'd cover it.

It was Day 4, the second day of SCA Sensory Intermediate.

Unless you're taking the course, you're probably not dying to know the details of papillae. The tl;dr is that they are the bumps on your tongue that contain most of your taste buds. Different kinds of papillae are more sensitive to different taste modalities and tend to group around certain areas of your tongue. It's not as clear cut as the "tongue maps" we saw in school imply; you're tasting all modalities in every part of your tongue (just to different degrees).

There are four main kinds:

• Fungiform: Mostly sense sweet. Make up ~50% of your gustatory papillae. Tend to be on the tip of your tongue. Mnemonic: "Fungiform sounds like fungus. Fungus grows in sugar. Sugar = sweet." Fungiform means "mushroom shaped", so that's not too far off.
• Foliate: Mostly sense salty and sour. Make up ~25% of your gustatory papillae. Tend to be on the sides of your tongue. Mnemonic: "The fo- in foliate kinda sounds like pho. Pho is sour and salty."
• Circumvallate: Mostly sense bitterness. Make up ~25% of your gustatory papillae. Tend to be in the back of your tongue to trigger your gag reflex, since bitterness usually indicates something you shouldn't eat (e.g. poison). I don't have a mnemonic for this, but it's the only one that doesn't start with "F", and humans are way more sensitive to bitterness than the other taste modalities.
• Filiform: These papillae don't sense a taste modality, but instead they sense tactile sensation (i.e. mouthfeel). They aren't counted as gustatory papillae (0%). Mnemonic: "Filiform sounds like feel-i-form, and filiform detects touch."

An Imposter in Coffeeland

Here's one of the moments that I kept jumping back to and made me wonder if I was crazy to attempt to take the Q:

I've always had to work harder than my friends to taste things, I just didn't realize until relatively recently that I could eat something and completely not think about how it tastes or smells. I grew up with bad allergies that meant I couldn't smell for large parts of the year. I enjoy food and I enjoy flavor – I just didn't realize that what I was tasting wasn't quite the same as everyone else.

It wasn't until I started to get into coffee that I realized that my ability to perceive flavor was different from my friends'. I helped organize events for the coffee club at work, and I put together tastings at home with my friends, but almost every time, when other people perceived a huge difference, I'd only perceive a slight one.

Feeling like you're different is a great way to trigger your imposter syndrome. You can't in good conscience claim that coffee should be respected because different coffees taste different and then be unable to taste that difference consistently. Instead I found that there's a lot to hide behind in coffee: everyone perceives taste differently, different brew methods and equipment can produce very different cups from the same beans, and the perception of flavor can be heavily influenced by what you ate recently. It's pretty easy to regurgitate talking points from coffee YouTube in lofty prose without being sure that you've experienced it yourself.

Flavor Isn't Really About Taste (Mostly)

One of the big "aha!" moments for me was grokking that "flavor" involves your tongue, your nose, and your brain. Flavor is a combination of what we taste (sweet, salty, sour, bitter, and umami) and what we smell. Sources disagree as to exactly how much taste and smell individually contribute to the overall experience of flavor, but smell appears to be the lion's share: if you pinch your nose and try to guess what flavor is in your mouth (e.g. from a jelly bean of unknown color), you're going to have a hard time. When you "taste" the flavor of a blueberry, it's your nose that gets all the floral, fruity sensations that make that berry unique. Your tongue is only sensing the basic taste modalities: the flesh is sweet and sour, and the skin is a little bitter and a little sweet or sour. Those same tastes could just as well describe any number of other berries: raspberries, blackberries, strawberries, and so on.

Our model of taste is simpler than our model of smell: we can enumerate basic taste modalities (even if there are debates on whether more exist), we have a somewhat intuitive model for how it's detected (papillae contain taste buds that are more sensitive to one modality or another), and we have substances that can evoke them in an almost "pure" form (e.g. sugar for sweetness, salt for saltiness, or citric acid for sourness).

By contrast, smells are more complicated: we don't have basic building blocks for smells or named receptors for them. Smell is more innate and primal in a way: the olfactory epithelium in our nose contains receptors for (we think) 400 or so odor molecules. These are wired into the olfactory bulb, a disco ball of sensory neurons that helps us interpret smells and plugs directly into the limbic system, which processes emotions and memories, bypassing the cerebral cortex. We name smells by comparing them to what we've already smelled, basically by pattern matching. We're taking readings off of a chemical analyzer (our olfactory bulb) and trying to fit our readings to a model of what we've encountered before in the world.

It's unstructured, kinda like a Rorschach test or cloud gazing, and it's hard to consciously think about. Usually, when we smell something we recognize, it triggers a snap association in our brains without us having to think too hard about it. But when we smell something like coffee, which can have a bouquet of interesting chemical signatures that don't cleanly match our model of any specific thing we've encountered (except, maybe, "it tastes like coffee"), we're left with something amorphous and hard to describe. If it's hard to describe, it's hard to remember, and if it's hard to remember, it's hard to compare from cup to cup or from day to day. So it can be frustrating and hard work to decipher if a coffee tastes like blueberries because it probably doesn't contain all of the markers that signal "blueberries" in our memory.

If we compare flavor notes to musical notes, it's like my memory of blueberries is a complex, jazzy chord with four or five notes stacked on top of each other, each representing a different odor sensation: e.g. a high grassy note, a tense floral note, a low berry tone, etc. A coffee that tastes like blueberries is like a moving melody that hits a couple distinctive notes in that chord, but not all of them. Analyzing music requires an understanding of music theory, a memory of chords and shapes, and then a lot of guessing-and-checking to come up with a hypothesis for what chord a handful of notes belongs to. Even then, it's often unclear and open to interpretation, both in music and in flavor.

All of this makes "Does this smell like blueberries?" a much harder question to answer than "Is this sweet?". It's a much more cerebral process with an unclear answer, and you have to arrive at a conclusion before the aroma fades.

In a way, this is also freeing: if a bag of coffee has "blueberry" written as a flavor note on it, it doesn't mean that it will smell or taste like a bucket of fresh blueberries. It only means that the particular bouquet of aromas and tastes in that coffee created the impression of blueberries in the mind of whoever wrote that flavor descriptor. It may very well create that impression in your mind as well when you drink it, but it very well might not, and that's totally fine too. Whether you get blueberries, a different fruit, or no fruit at all depends on your memory of those foods and the way your flavor sensing system interacts with that coffee.

More Structured Ways to Smell

So what was I doing when I was actively trying to look for a flavor note in the coffee outside Equator with Eugene? Turns out that all that slurping, swishing, and concentrating are pretty useful ways to actively smell.

Air goes two ways through your nose: you can breathe in, and you can breathe out. (Unless you're me in elementary school, in which case you can't do either of those things most of the year. Thanks, hay fever!) As air passes through your nose in either direction, you perceive smells. However, the smells you perceive breathing in are not the same as the ones you perceive breathing out. When you breathe in or actively sniff something, we call that "orthonasal olfaction". However, when you have something in your mouth (say, a strawberry or a sip of coffee) you perceive its aromas as you breathe out. We call this "retronasal olfaction" because the air flows in from the back of your nose. It's a big part of how both flavor and aftertaste work.

The Flavor book explains that these two forms of smelling work differently in two big ways:

1. What we're smelling is different. We smell the "outside world" with orthonasal olfaction (e.g. sniffing or breathing in), while we smell what's inside our mouths with retronasal olfaction (breathing out, aftertaste). When we breathe in, the current of air going in acts as a curtain, keeping the odor particles from inside our mouths from reaching the olfactory epithelium in our noses. This lets us get an accurate measurement of our environment or evaluate something that we're about to put in our mouths. When we breathe out, it works the opposite way: we're sending odor particles from inside our mouths up and onto the olfactory epithelium from the back.
2. Which smells we're sensitive to is different. The receptors for the 400+ different odor molecules we can perceive are not uniformly spaced out in our nose. It's a bit less clear how they're arranged (even compared to the already-inaccurate tongue map), but we think that some sensors tend to group in the front or back of our olfactory epithelium (and I'd bet that like the arrangement of papillae on the tongue, it's different for each individual). This acts as a filter over what we smell, sorta like how in audio you can have a high-pass filter (which ignores all the low frequencies) or low-pass filter (which ignores the high frequencies). Mechanically, this is because odor particles need to physically reach their matching receptor cells to contribute to the smell, which means they have to stay airborne long enough to reach them. Many molecules are heavy and will get caught in our mucosal lining before reaching their receptor, which filters them out of the smell. If a type of receptor is in the front, then we might get more signal from it during orthonasal breathing where the air comes in from the front, and less signal from it during retronasal breathing where the air comes in from the back and the molecules have a greater chance of being trapped before they can activate the receptor. That's probably one of the many reasons why coffee grounds smell very different from the flavor of the final drink.

When I slurped the coffee, it aerated the fluid, helping more volatile odor molecules to fly free of the liquid and get suspended in the air, where it could flow over my olfactory epithelium during retronasal breathing and get detected as flavor. It also ensured that the coffee fluid got all over my tongue so that each of the different types of papillae had a chance to measure how sweet, salty, sour, bitter, or umami it was. It's a similar story for swishing, gargling, holding the fluid in my mouth for a bit before swallowing, and doing that lip-smacking thing where you tap your tongue to the back of your teeth (and alveolar ridge). When I focused on searching for the flavor, I breathed more slowly and evenly, which might have helped optimize how far the odor molecules made it on my olfactory epithelium in both orthonasal and retronasal olfaction.

It's clear that I looked pretty silly (and maybe obnoxious) trying to enhance my experience of the flavor, but that's what it takes for me to maximize the opportunity for my senses to capture and analyze as much of the flavor as I could.

Maybe it's fair for Eugene to laugh at all this. That's a lot of work, just to drink coffee.

Theory, Meet Practice.

We did a few practice cuppings to get us used to the procedure of setting up and conducting a cupping. This also kicked off the process of getting calibrated in the way we assessed and scored the coffee, a process that would continue through the next week for those of us sticking around for week two to take the Q. The highest and lowest rated coffees quickly made themselves known; when you put that many coffees next to each other side by side, the differences stand out.

The best thing on the table was La Mula, a Panama Gesha developed, grown, processed, and roasted by Willem Boot, the leader of the coffee lab (his name is on the building) and our instructor for the Q. The sweetness and floral notes were bursting out of the cup from the fragrance of the ground coffee to the aftertaste of the brewed coffee. I was floored by how much flavor I was tasting consistently in every slurp and surprised at how quickly words, opinionated words, jumped to mind: the citrus-like acidity reminded me of yuzu, the body and tangy sweetness of Yakult, and the lingering finish like a milky oolong tea.

La Mula Gesha Lot 25 – La Mula Coffee

Sweet citrus acidity, aromatics of lemon, orange blossom, but also berries like blueberry. This coffee is shade grown under the canopy of local native trees in the tropical cloud forest of Panama. ORIGIN: Panama FARM: Finca La Mula ELEVATION: 5,906 feet (1800 meters) PROCESS: Natural

La Mula CoffeeName *

The other thing that was surprising was how quickly the class started to converge on a set of scores. There were some inconsistencies between different people, and I had one or two samples that I rated way too high or too low due to scoring issues, but after we discussed each coffee, it was surprising how many of us found similar flavors using slightly different descriptors, and how our cumulative scores could be similar despite different ratings for each individual attribute.

Over the course of two or three cuppings, almost everyone was binning each coffee into similar ranges. Even if there was a couple point spread, we were consistently putting the highest grade coffees in the high-specialty range (around 87+), and the lowest grade coffees in the non-specialty range (around 80 points, which is the cutoff for specialty grade).

Armed with the theoretical knowledge of how flavor works, I started to make adjustments to the way I tasted and smelled:

• I discovered that when my brain wasn't awake, my nose wasn't awake. I needed to eat a bit and drink some coffee to wake myself up before I could start analyzing coffee. Before I'm warmed up, everything just tastes like coffee.
• I realized that my glasses were sinking down on my face over time and when they got too low, they'd pinch my nose, making it harder to smell. I started to clean my glasses more or even take them off when I was going to smell a lot of samples in a row.
• I figured out how close I needed to get to the cupping bowls to smell the fragrance and aroma of the coffee (turns out: pretty close). I also discovered a trick where sniffing while moving my nose slowly back and forth above the lip of the bowl would create some contrast and help me find the spot where the fragrance was strongest.
• I settled on a breathing exercise where I'd breathe in slowly through my nose at around the rate that helped me smell the best and then breathe out slowly, first through my mouth, then through my nose. I think it was one part mental preparation, one part practicing the motion of smelling, and one part priming my body to open my airways.
• I picked a few different ways to move the coffee liquid around in my mouth to aerate the aromatics and feel the texture. My slurping got a bit more confident too – there's a bit of aim involved to get it all over your tongue without getting it into your throat, which will make you choke.
• I got better at knowing when my sense of taste was saturated and how to take a break and rinse out my mouth. Similarly, I picked up a trick whereby I would sniff my clothes when my sense of smell was getting saturated, the theory being that your own scent is neutral.

With all that in place, I was starting to feel more consistent, and since my inconsistency was my greatest fear going into the class, I was finally starting to feel more confident. After a couple sessions I thought, Ok, maybe I can actually do this.

Break Your Brain

A week of nonstop coffee drinking and coffee talk will fry your brain in addition to your palate, but sitting in the lab after class on day four, as I watched Valerian roast coffee for the next few days of classes, I realized that I had experienced a deeper paradigm shift.

It reminded me of when I saw people learn computer programming for the first time. On the surface, writing code looks similar to the way we humans teach and instruct each other to do things: if this is true, then do that. We talk this way all the time. But when you start to write code, you realize that computers work in a much more rigid, much more literal way. They don't assume things because they don't have a model of the world besides what some programmer has explicitly spelled out for them. They can't generalize, and they don't handle edge cases that are "close enough", because they don't know what "close enough" means until you tell them. (Machine learning and LLMs like ChatGPT are changing some of these assumptions, but let's set that aside for now.)

Many of the first-time learners I've seen go through this journey where at first it seems to make sense ("If the number is even, then do this thing."), then they hit the point where the abstraction breaks down and they need to express concepts in the computer's terms instead of in the human terms they're used to ("What do you mean I have to define what 'even' means? Isn't that obvious?"). Then, they struggle for a bit as they learn the structure of how a computer "thinks" and the basic building blocks they have to express their logic ("An even number is a number that can be divided by two with no remainder. We can use the modulus operator to do this test."). Finally, there's a moment when something shifts and you can see that they've internalized the structure and limitations of computer programs, and they're no longer trying to bend the syntax of a programming language to match their human experience of reality, but engaging the computer on its own terms.

It's the moment where they go from "this makes no sense" to "this is hard, but I can do this". It's a hopeful and intimidating moment: like you can hear the machinery inside their head shear, rotate, tumble a bit, and finally settle somewhere a bit lower to the ground but much more stable than the cliff they were holding on to. It's both the moment where they realize "my experience instructing other humans isn't going to help me program computers", but also the moment when they realize the monumental power of what they've just unlocked: even though the primitives are simple and it feels like you're sitting on the ground playing with Lincoln Logs, you truly believe that you will be able to apply powerful concepts to these primitive building blocks over and over again until you've built a skyscraper.

That's how I felt after I started to internalize what I was learning about flavor. Generally speaking, it's not a matter of hardware: to paraphrase the Flavor book, if you can taste the difference between a blueberry and a raspberry, you have what it takes to taste the notes in coffee. It just takes practice and an awareness of what to look for and how to build your memory of aromas. Some people might do this innately, but others (like me) need some coaching and coaxing to start down this path. It requires familiarizing yourself with your instruments and discovering how your senses respond to different tastes and smells. It helps to explore how the way you experience something differs from how someone else experiences it. Sometimes, you have to commit to looking ridiculous and putting your nose to your plate of food or some fresh fruit in the produce aisle. For me, it means being conscientious of what conditions my body needs to taste and smell, and being intentional about stopping to taste and smell everything I encounter–coffee or otherwise.

Further Reading

Flavor: The Science of Our Most Neglected Sense

A journey into the surprising science behind our flavor senses. Can you describe how the flavor of halibut differs from that of red snapper? How the taste of a Fuji apple differs from a Spartan? For most of us, this is a difficult task: flavor remains a vague, undeveloped concept that we don’t know…

Google Books

Flavor: The Science of Our Most Neglected Sense by Bob Holmes, has a bunch more info on how we perceive flavor. Valerian recommended it in class, and there's a bunch of the cool tidbits in here (e.g. did you know that you have taste buds in your lungs and intestines?).

I consumed it as an audiobook, and it was a fun listen. The content in it is about flavor generally, and he tells stories about coffee, wine, whisky, tomatoes, hot peppers, and other foods to illuminate his (rather scientific) exploration into flavor. Coming out of the book, I'm even more convinced that flavor is something we invent in our brains. He lays out some of the concepts I mentioned in this post early on in much greater technical detail, but then goes on to explore how other factors besides smell, taste, and mouthfeel can affect our perception of flavor. Things like placebos and expectations (e.g. people don't show a preference for organic produce in a blind taste test, but may genuinely perceive it to taste better when they know that it's organic), how aromatics can trick our brain into thinking something is sweeter than it actually is, and so on. Definitely a fun book to nerd out on.

Sip’n’ Slurp: A Guide to Expert Coffee Tasting | Freda Yuan Offical

About Sip ‘n’ Slurp: A Guide to Coffee Expert Tasting Sip ‘n’ Slurp is the first self-published coffee sensory book by Freda Yuan. This book provides unique insight into using tasting coffee to embrace life and find a sense of joy in the pleasure of drinking coffee. Inspired by the author’s own per…

Freda Yuan Offical

Sip'n' Slurp by Freda Yuan, is about how to taste coffee. It briefly covers her journey of how she immigrated from Taiwan to London, dealt with her insecurities and mental health issues, and became a competition winning cupper (professional coffee taster). The majority of the book is about how to perceive flavor generally. A lot of what she said lined up with what I learned in SCA Sensory as well as what was said in the Flavor book, but she presents it in a concise way accompanied by very stylish photos that look straight out of Instagram. She also includes some exercises for familiarizing yourself with your sensory instruments, examples of words you can use to describe a coffee's flavor and mouthfeel, and some techniques she uses to visualize a coffee when she tastes it. It's a quick read and clearly a very personal project, and I think it's worth picking up.