Last week I took part in a coffee event, a barista competition of sorts, in Denver. CO. I had been asked to come down and deliver an interesting tasting experience. I was scratching my head for the better part of the week trying to decide what I might do for this particular event when I was lucky enough to receive some coffees from a roaster in Chicago who had purchased the coffee via Coffee Shrub. Among the coffees were two different roasts of the same Kenya, a coffee that I was already familiar with through my own tasting so I though it could be a great way to gather some notes for the roaster from a decent sized crowd as well as serve the purpose of the talking point coffee for the event.
As many of you have probably read here and otherwise in the Sweet Maria's Library, I've done plenty of side by side comparisons of different roasts of the same coffee. In order to make this particular tasting a little more interesting I added one more element. We would look at the two different roasts side by side via cupping, but then we would also look at the coffees side by side via a Chemex brew with a paper filter. How would the paper filtration affect our ability to taste the difference between the two roasts of the same coffee?
Now, the difference between the two roasts appeared on the surface to be a rather small difference, about 30 seconds of time during the first crack. During this point of the roast there is ongoing caramelization. It's the point of the roast where the cellular structure of the coffee is at its most elastic and the cellulose is breaking down into non-sugar complex carbohydrates that can lend themselves to perceived mouthfeel.
The testing was blind but the results were quite telling and almost universal in terms of preference. Most people who took part in the tasting preferred the slightly longer roast, saying it had more sweetness, more potent of a dry fragrance, and a longer more fruited finish. The shorter roast was still very nice but had more aggressively bright acidity in the front of the palate with a drier, shorter finish. The preference was overwhelmingly the longer coffee. The really interesting part is that the differences between the roasts were much more evident through the Chemex brew with the paper filter. Generally, the sweetness, the perceived acidity and where they were perceived on the palate were much clearer in the filtered brew.
The cupping brew is much closer to a press pot brew and the thicker liquid can in some ways make it difficult for some tasters to look past this extra perceived mouthfeel. Cupping is honestly a method used for evaluating the coffee's quality itself, and not necessarily the differences in roast. This is not to say that cupping to look at roast differnces is bad practice, but it can be really eye opening to look through the coffees through more than one method.