Case Study 1 — Danny Reyes-Park Cups Three Yirgacheffes

In late October, the green-coffee buyer at the fermentation-focused restaurant where Danny Reyes-Park worked weekends arranged a small training session. The owner, a woman named Hannah Pak, had been working for two years to upgrade the restaurant's coffee program from "good enough" to "the part of dinner the regulars come back for." She had hired a green-coffee consultant — a former Q-grader (a certified coffee taster) named Ravi — and Ravi had brought three Ethiopian Yirgacheffes for the kitchen team to cup.

Cupping is the standard method for evaluating green coffee. The procedure is rigorous: 8 grams of medium-ground coffee, 150 grams of 200°F water, no filter, 4 minutes of steeping, then a "break" where the taster cracks the surface crust with a spoon and inhales the released aroma, then a slow tasting with a spoon as the brew cools. The same coffee is cupped at three temperatures (hot, warm, cool) to capture the full flavor evolution.

Danny had cupped coffee a dozen times before in his food-science classes. He had not cupped Yirgacheffes side by side from the same farm with three different processing methods. That was Hannah's training session.

Ravi laid out the three samples on the cupping table.

"Same farm. Same elevation. Same harvest. Same variety — Ethiopia heirloom landrace. The only differences are processing. One is washed, one is natural, one is anaerobic."

He did not tell them which was which. The three small piles of brewed coffee sat in identical glass cups, labeled only A, B, and C.

The cup

Danny worked through the protocol the way he had been trained. Sniff the dry grounds, sniff the wet grounds, break the crust at exactly 4:00 minutes with a deep slurp inhalation, scoop the floating particles off, and then taste at intervals as the cup cooled.

Cup A smelled, dry, of citrus and tea. Dry-fragrance descriptors he wrote down: lemon zest, jasmine, faint black tea, a touch of grass. After the break, the wet aroma added a slight floral note — bergamot. The first sip, hot, was sharp and bright — a high citric acidity that hit the front of the tongue and faded quickly. Body was light. As it cooled, the citric edge softened to a more rounded lemon-and-honey sweetness, and a faint tea aftertaste settled in. The cup was, as Ravi had predicted in his preamble, "tea-like, with high acidity."

Cup B smelled, dry, of strawberry jam and red wine. Danny inhaled twice to be sure. Wet aromatics intensified the fruit — now blueberry was clearly present, alongside a faint funky note that he had not encountered in many coffees before. Like a slightly fermented thing. The first sip, hot, was syrupy and heavy — a much fuller body than Cup A — with prominent fruit, cocoa, and a vinous quality. Acidity was present but lower, more like a malic or stone-fruit acidity than the citric of Cup A. As it cooled, the fruit deepened toward red wine and dried apricot. The aftertaste was long and sweet.

Cup C smelled, dry, of something Danny had never quite encountered in a coffee. Tropical fruit — pineapple? Mango? With a strong floral overlay, almost gardenia. Wet aromatics added what he could only describe as "buttery" — a faint diacetyl note like popcorn or buttered cream. The first sip was intense — the tropical fruit hit hard, the mouth feel was unusually heavy, and there was an almost-spicy quality at the finish that he could not name. Acidity was complicated — present, but layered. As it cooled, the fruit became more dominant and slightly more dissonant.

Danny sat with his three cups, scoring each on the SCA cupping form. The numbers came out roughly even — each cup was in the 86–88 range, all "specialty grade" by SCA standards.

But the characters were entirely different.

"Okay," Hannah said. "Guesses?"

Identification

Danny went through what he had observed.

"Cup A is washed. The clean profile, high citric acidity, light body, tea-like quality — that's the textbook washed Ethiopian. Cup B is natural. Heavy body, fruit-forward, blueberry, vinous — that's classic natural. Cup C is..."

He paused.

"Cup C is something I've never tasted before. The tropical fruit and the diacetyl note suggest controlled bacterial fermentation. Anaerobic, probably with intentional inoculation. Maybe a 36-to-72-hour sealed-tank ferment."

Ravi smiled.

"Yes. All three correct. Cup C is from a producer in Sidama who started doing anaerobic experiments three years ago. He uses a custom yeast strain, ferments in stainless tanks at 22°C for 60 hours, then dries on raised beds for 14 days. The diacetyl is from a Lactobacillus species that the yeast lets dominate in the second half of fermentation."

The four people at the table tasted Cup C again now that they knew what it was. Ravi pointed out that the tropical character — the pineapple, the mango — was almost certainly a product of the controlled bacterial fermentation, not the bean's intrinsic character. The same beans, processed washed, would taste like Cup A. The fermentation had built flavors that no amount of careful roasting or brewing could otherwise produce.

Hannah turned to Danny. "So which one do we serve?"

The decision

This was the part Danny had not been ready for. He had thought the lesson was "taste the difference." He had not realized the lesson was also "make a business decision about which difference to feature."

Hannah laid out the considerations.

"Cup A retails at $24 per pound at our wholesale price. Cup B is $32. Cup C is $58. Our coffee program has to make money. We also have to choose what story we are telling. Customers who pay $7 for a small pour-over want to know they got something."

Danny thought about it.

"Cup A is the one most people would order if they didn't know about coffee. It's clean. It's recognizable. It tastes like 'good Ethiopian.' Cup B is for the regulars — the people who already know they like naturals. Cup C is for the once-a-week event coffee, the thing we charge $14 for and tell a story about. We can't do all three regularly because the volumes won't support three Ethiopians, but we can do A as our daily, B as our seasonal alternate, and bring in C for tasting events."

Hannah nodded slowly.

"That's about what I was thinking. But you're missing one thing. Cup C is grown by a single farmer who needs reliable buyers to keep doing experimental processing. If we don't buy from him at the prices he can sustain, the experimental fermentation tradition stops. We need to be in his rotation. So Cup C isn't just an event — it's a relationship investment."

Danny wrote that down.

Six weeks later

The Yirgacheffe rotation went into effect. Cup A — labeled on the menu as "Yirgacheffe Aricha, washed" — became the daily pour-over option. It sold steadily; customers liked it. Cup B — labeled "Yirgacheffe Aricha, natural" — was available on Saturdays only, at a $2 premium; it sold out most weeks. Cup C — labeled "Yirgacheffe Aricha, anaerobic, lot 2024-A1" — was offered at twice-monthly tasting events at $18 per cup, with Danny or Hannah pouring and explaining. The events were popular and built a small following of regulars who came specifically for the experimental coffees.

What surprised Danny, three months in, was that the customers most likely to order Cup C at the tasting events were not the ones with the most coffee knowledge. They were the curious — the people who wanted to taste something they had never tasted before, the way a wine drinker might pay more for an unusual varietal. The coffee experts often preferred the washed (Cup A) for its clarity and balance.

Analyze this

For the reader: walk through Danny's cupping in the language of the chapter.

1. The three cups taste so different that they score similarly on the SCA cupping form but produce very different sensory experiences. What does this tell you about the limits of a single quality scale for evaluating fermentation diversity?

2. The tropical fruit and diacetyl notes in Cup C come from microbial activity, not from the bean. What does this say about the relationship between terroir (origin) and processing in specialty coffee?

3. Hannah argues that Cup C is a "relationship investment" — they buy it not just because customers like it but because their purchasing keeps the experimental tradition alive. Is this an argument food businesses should be making? What does it tell you about the economics of fermentation experimentation?

4. Anaerobic coffees are sometimes accused of "tasting like fermentation, not like origin." Did Cup C fit that criticism? Were the tropical fruit notes an expression of Ethiopian terroir or a fermentation engineering choice that obscured terroir?

5. The Q-grader Ravi described Cup C's process: 22°C, 60 hours, custom yeast strain, Lactobacillus dominance in the second half. What does this tell you about how scientific the modern specialty coffee fermentation toolkit has become?

6. Compare Cup C's anaerobic fermentation to traditional cacao fermentation in West Africa. What is the same? What differs? (Hint: cacao is open-air, multi-day, multi-species microbial succession; anaerobic coffee is sealed-tank, single-strain-dominant, controlled.)

7. Danny's prediction that experts would prefer Cup A and curious-novices would prefer Cup C turned out to be true. Why? What does this say about how fermentation flavors are perceived across different consumer segments?

Closing note

Danny's cupping at Hannah's restaurant illustrates the core argument of this chapter: fermentation is not a side step in coffee production; it is the step that defines what the cup will taste like. The same beans, processed three ways, became three different coffees — and the differences came from microbes Danny could not see and would not encounter directly except as flavors in his cup.

This is theme #4 of the book in its modern industrial form: food traditions are accumulated scientific knowledge, but in the case of specialty coffee, the tradition is being rebuilt in real time, by farmers who are now consciously experimenting with fermentation conditions in ways their ancestors could not have planned because microbiology was not yet a discipline. The Doi Tung farmer experimenting with sealed-tank fermentation, the Sidama farmer using custom yeast, the Costa Rican grower trying yellow honey versus black honey — they are doing food science. They are publishing their results in fermentation logs. The science we are naming, in this chapter, is what those farmers are now actively building.