by another_jim on Fri Feb 05, 2010 6:14 pm
You can use a wider range of roasts for brewing than for espresso. In an espresso shot, the acidic light roast flavors (unsweetened fruit and flowers), the Maillard flavors that develop before the first crack (grassy, woody, bready & nutty) and the dark roast distillate flavors (spice, smoke, tar) taste more intense in relation to the buffering middle flavors (sugars, caramels, vanilla & chocolate). This disqualifies very light and very dark roasts, as well as roasts that have taken either too long or not long enough reaching the first crack. Good espresso roasting also uses profiles that retain as much sugar or light, sweet caramel as possible in the finished roast.
In practice, the range for brewed coffees runs from roasts stopped right at the end of the first crack (415F) to roasts taken beyond the end of the second (465F). For espresso, the lightest roasts practical roasts are mostly just before the second crack starts (430F), and the darkest where the 2nd crack starts tailing off (455F). The measures I have given are nominal bean surface temperatures, and can vary by as much as 10F from roaster to roaster.
Finally, and most importantly, if you are drinking auction and competition coffees, the emphasis moves from the preparer and roaster to the farmer and the farm. You are no longer the star of the show, and your job is to best preserve and convey what is in the bean. In practice, this means that the coffees should be roasted as lightly and as quickly as possible for the prep method envisaged, and you should only use the prep method that most individualizes the flavor of that coffee. For instance, if someone offers you a Vienna roast Esmeralda espresso shot, you know you're dealing with the coffee equivalent of a nouveau riche fathead.