On Matching Roast to Bean
Kevin Knox writes: In tasting through the Costa Rican samples for the June 2002 article Cupping with Ken Davids (and Kevin Knox): Costa Ricas, I was struck by the fact that while the samples represent a broad range of roasters, the range of roasts applied to the coffees was exceedingly narrow, ranging from moderately dark traditional full city (chestnut brown, no oil) in a few cases to quite dark in many instances. According to Specialty Coffee Association of America figures, the average Agtron (M-Basic) number for United States specialty coffees is 42. Meanwhile, the average roast in Scandinavia, which buys the highest quality coffee in the world overall and also has by far the highest per capita consumption, is probably 20-30 points higher (lighter) on the same scale.
In recent years there has been a noticeable "shrinking of the bandwidth" in the offerings of American specialty roasters. With rare exceptions most craft roasters roast all of their coffees in a range from moderately dark to very dark by international standards.
There are any number of reasons why this is the case. One is that few smaller roasters have had the chance to apprentice with expert cuppers and are often largely or entirely self-taught. The tendency under such circumstances is to roast aesthetically, and coffee evens out in appearance and is at its most appealing from a visual perspective when the beans have entered second pop. Then there is the huge matter of the influence of Starbucks and its many imitators, who are shaping consumer palates on what can seem like every street corner in the country to associate the smoky tang of dark roast with sophistication.
Roasting into second pop is certainly a valid style, but few roasters who pursue it understand what's required to do it artfully. If you want to go dark but still have discernable character related to origin you need to be buying the very best, densest, highest acid and most expensive green coffees available. If not, you will have an entire menu board of coffees, which, if tasted blind simultaneously, might yield three or four slightly different flavor experiences. Moreover, even the best coffees today (coffees which few smaller roasters even have access to) do not display the density and acidity those same coffees did 10-20 years ago. Having tasted and done Agtron readings of coffees from several of the more famous "deep" roasters for the past two decades I can assure you that the more savvy among them are roasting significantly lighter across the board than they used to.
The sound of second pop is the sound of cell walls rupturing. When you enter this range of roasting each pop means that aroma and origin character are being extinguished. The trade-off, provided the roast does not go too far (and things happen very quickly once into second pop), is an increase in body. You are, so to speak, turning still wine into sherry or port - not a bad thing - but it would be a shame to distill all that good wine without first consciously exploring the diversity of flavor and aroma of a broader range of roast choices.
Medium-dark roasts are at their best in plunger pots and espresso machines - brewing methods that are all about body and mouthfeel. Classic full city roasts - chestnut brown but no second pop and no surface oil - taste far better brewed in a vacuum pot or its convenience-oriented near-relation the drip brewer - methods which highlight aroma and character related to coffee origin. It should also be noted that soft water is critical to having any sort of supporting acidity left when brewing deeper roast styles, and it is no accident that the most popular purveyors of such styles evolved in places like Seattle and San Francisco with naturally soft water.