What it Was Was Bitter ...
Since the druggist was sayin', over a cup of "Coffee of the Year, Las Mingas", that caffeine, that trimethylxanthine, in the pharmacopeia is listed as a chemical that is odorless and tasteless, to be compounded where an increase in metabolism is indicated, I turned to il Professore of Scoula di . . , because all my references say caffeine contributes to the bitter taste of coffee as much as any other component.
Our Professore looks astonished and pulls down Flament, Coffee Flavor Chemistry (2002) to page 14. "No chemist doubts", says the Professore, "that caffeine is bitter, yet it's role in taste is limited to around 10% of total bitterness. It is unaffected by heat itself, decline is modest or stable in relation to overall weight loss in roasting, but increases in solubility by 10 times at least as the temperature comes up to drinkable hot, very soluble.
"Why am I", continues il Professore, "so bent upon the results of my espresso shots? Because of an approach to cupping-roasting which controls bitter outcomes, but leads to intensity, dimension, and rivers of crema, that I call: Pulling Shots through the Roaster--Staging Roasts for Cupping Shots!
"Do not give up on me. . , but read about it in three parts: Pulling Shots Through the Roaster, Culling Current Chemistry of the Mystery, and then "Staging" is Where it Leads.
Pulling Shots Through the Roaster? Part I
Uh, no, it's not that shots are somehow coming out of the roaster in a sort of mechanical misstep. It's instead a shift to an emphasis on roasting near to the "espresso" style and to the judging of the outcomes of the roaster through the espresso machine, through shots of espresso. It means searching for roasting regimes to maximize the mid-range characteristics of development and of the cup, what can be called "staging". It means depending on shots to judge cup quality as much as keeping on with the technical cupping routine--not to replace, but in addition to, traditional cupping.
Pulling shots and then developing stages in roasting leads away from formulary roasting, even from current time and temperature curves. An examination of the artistic sense of roasting and matching that with current science in coffee chemistry moves toward pinpointing and manipulating roast regimes with intense results.
Working with shots expands the traditional cupping table routine. "Cuppings" in the international league are necessarily well-developed comparative exercises with standard practices, with set and predictable lab-like procedures. The cupping tables are exemplary for their displays of well-developed acidity in front-ends or the absence of it, intensity or lack of it, and sorting out the apparent defective cups. Incorporating espresso shots as routine is a conceptual expansion of the role of tasting the roast styles to which we have become habituated. The senses are called upon to explore the capture of aroma, the texture and longevity of the crema, smoothness against grainy bitterness, the unfolding of front-middle-end notes, and the relative balance of sweet-sour.
Expressly for Espresso
Sweet shots are the lore of aristocrats of espresso roasting. Probably there is at least one marque in every great roaster's inventory close to the traditional Italian espresso blend. Consider Intelligentsia's intellectually intense "Black Cat", Stumptown's hard-hitting "Hair Bender", the pearly pour of Gimme's "Platinum Blond", or one of David Schomer's cult classics. By the way, none of these are hefty black, oily darkness, but mahogany blends of striking palate. No backlash bitterness. All could stand as daily brews of residing sweetness and depth.
What is that something about a legit "Italian" shot? Consult Illy and Viani, Espresso Coffee: the Chemistry of Quality (ed. 1995) for details about italo-shot mechanics and chemistry of the renowned polymodal, polyphaisic 30 milliliters at 30 seconds. But the roadmap of espresso roasting is still not clear. Turn to the famous houses for some suggestive clues of the way to roast for sweet-low acid, for texture, crema, and so forth. For example, Rome's Caffe Eustacio roasts slowly in a drum roaster and lets it be known that it ages the greens for over a year or more. Could that be the technique to enhance sweet mid-range tastes?
Cupping Through the E61
The question remains unanswered, so try cupping with companion cups: one is the traditional infusion, for slurp and spit; the other. . . have the espresso machine standing by. Say the very venerable Faema E61. Pull and taste shots while the traditional cups cool down after the crust of each sample is broken, perhaps. Then the shot is its own verification of the valor of the origin or blend being investigated: a shot as a new gateway to taste.
And naturally, the espresso machine, the grinder, and the shot technique have to be of the same caliber as the rigorous routine of straight cupping.
In the case of the E61, the design of the head is proven by the pours: glossy slow syrup carrying a tattoo of mottle and spoonfuls of crema. Examine the re-make of the E61 for an alternative, the Faema Legend, or the glamour model Mirage Veloce from Kees van der Westen for the very same head. The boiler of the E61 is nuclear reactor heavy, massive, copper brass. There is no auto-fill that will surge on and off during shots. The head can be manually opened to line pressure, less than two bars, for puck saturation before infusion; the switch to pump pressure brings a mudslide oozing out. Part of the magic though is the new Barksdale pressure stat backed by a solid-state relay and heat sink. It has an operational differential of 0.5 psi or 0.04 bar, keeping the boiler with 1 degree C.
The grinder is the formidable Istituto Espresso Italiano certified, conical Luigi Mazzer Robur. It is a 60-pound tower turning the interior cone slowly and quietly compared to conventional grinder-dosers.
How to do Sweet?
At this point, for argument sake say that the answer is: study the chemistry, cut the chlorogenics, increase caramelization, heighten the brown textures, fill out the aromatics, and add nuance with roasting by some method. Pull the shot and, indeed, when you hit the target, the pour is dark red liquor to start, viscous as molasses, mottling the sides and finishing tawny with sweet, sweet mouth and potent finish drawn through a blanket of rich texture. Masterful!
Part II, coming, will be a look at the applicable coffee chemistry.