Light roast? Dark roast? Medium roast? What exactly is roast degree? There are common industry demarcations like half city, city, full city, French, Italian, light, medium, and dark, to name a few. These tend to be loosely defined and not always uniformly alike. Most are measured in the roaster by temperature, which can vary due to the placement and accuracy of thermocouples in roasting machinery.
There is a West-Coast style which is historically darker than the East-Coast style, but even those are ever evolving. In the current mise en scène, there are roasters who claim to retain more of the qualities in coffee by roasting lighter and lighter (really a Scandanavian preference more than a trend from hipster-America). Is there a correct level to roast to? Is there one style that better exhibits the wonderful flavors of coffee we love so much? In this roaster’s opinion, yes, but the best level to roast a coffee to depends on the coffee itself. There is no single optimal roast degree common to all coffees.
To define the best in anything takes defined lines of quality. In coffee, so much is subjective. You either like it or you don’t. What I attempt as a coffee roaster is to fully realize the potential in each green bean. In the roasting process, complex poly-saccharides within the cellular structure of the coffee beans are converted from starches to sugars. Through the Maillard reaction, these sugars begin to caramelize, aided by the conductive heat of the roaster, the convective heat of airflow, and the supplemental heat of the exothermic beans. As changes in temperature become increasingly rapid, so does the volatility of the flavor compounds and aromatics in the bean. There are telltale signs an artisan roaster looks and listens for. There are aromas to indicate even more nuanced changes. It is precisely here where the predetermined end point of a computer profile differs from the instinct and experience guided judgement of a competent, practiced artist.
I believe coffees taste best when they are roasted until their sugars become perfectly sweet. To illustrate this example, take a bite from a marshmallow. Sweet enough right? Perhaps even cloyingly sweet. Place it over a fire and caramelize the sugars a bit. We've all done this around a campfire. Too dark and it tastes ashy, but it becomes much more satisfying with a little color on it. Same with a properly made roux, or BBQ ribs, or Persian rice, or home fried potatoes, or coffee.
To me, most coffees roasted on the lighter side taste raw and underdeveloped. The spectrum of flavors inherent in coffee is intensified and becomes fully developed only after a certain internal temperature has been reached and consequently, a certain level of caramelization of sugars has occurred. On the other hand, it's as easy to mis-identify a coffee as suitible for dark roast than it is to burn a coffee beyond recognition. Not all coffees are created equally. If you've ever tasted sour, bitter, or burnt tasting coffee, you know this to be true. This is why raw, green coffee selection is so important. Certain flavor and aroma specific descriptors like fruits and florals are delicate and should be treated as such, and maintaining them requires a deft touch at the roaster. Whereas heavier woody and earthy flavors shine at a slightly darker profile and can elevate a roast to sublime levels of complexity. Acid and body are often misleading or misidentified characteristics, and also most fleeting and difficult to pinpoint during the crucial final seconds at the end of the roasting cycle. In a light roast, inherent acidity can be masked by an astringency that conflicts with a coffees natural high notes such as citrus or florals. It’s often difficult to determine whether a coffee is acidic or under roasted. In a darker roast, a coffee’s body is more pronounced, but some of the delicate notes can be diminished, if not completely lost. An improper dark roast will result in bitter taste. More often than not, the use of coffees of inferior quality, unable to withstand the stress of a dark roast application are to blame for the unfair stigma associated with dark roasts.
The coffee roaster becomes a “DJ” of sorts. Spinning two records at once, maybe at varying speeds. Watching, listening, fully dedicated and present. Always at one with the beat, in the pocket, anticipating the sound in his head a fraction of a second before it leaves the booming speakers. Through proper roasting of quality green coffee beans, it is quite possible to enhance all of the high treble notes a coffee has to offer while establishing the lower bass notes to obtain the harmony and balance of a danceable groove. This is easier said than done, but can be accomplished effectively by a master of the craft. I cannot call myself a master coffee roaster. I can only apply what I know to be true to each batch I roast, with dedication and appreciation for the gift of coffee in a humble attempt to make it as delicious as possible. The proof is in the cup.