Every so often, you hear a sports reference to a person, team, or animal that beat incredible odds by performing on a recipe of "all heart." That team triumphed playing all heart. That horse ran on all heart. That athlete was all heart. It is always a statement of utmost admiration.
Today, I experienced an espresso against which all the odds were decidedly set. It was at a Barnes and Noble cafe, to begin with. And it was definitely existing on "all heart." But such a state, let it be noted, is not even remotely an admirable quality in an espresso.
Since this column as a whole aims to talk a fair amount about espresso quality, I thought it would be ideal to take a moment to talk about espresso's defining features. An opportunity to put us all on the same page, as it were.
Good espresso, by definition, consists of three mandatory stratum: heart, body, and crema. No good espresso can get by on only one of these. Much less, on heart alone.
In any shot of espresso, the heart is the darkest, base layer. It is inevitably the most bitter of the three layers, and the color which defines "espresso" in the world of paint chip. Ikea and Target rely heavily on the heart of espresso for their furniture collections.
The body of the espresso is probably the least discussed layer. The middle, caramel-colored, melding moment of a good shot. It is consistently the most difficult to quantify in terms of flavor or texture, and in a really quality shot of espresso, is the most ephemeral layer to attempt pointing out.
By contrast, Crema is espresso's front man. Crema is the top layer: the rich, bubbly, foamy surface that the coffee paparazzi stalk with irritating persistence. It is the espresso community's greatest celebrity, the barista's holy grail, and... all things considered, is shockingly mundane in its definition. Crema is what occurs when the carbon dioxide still trapped in a roasted coffee bean meets pressurized hot water. The right combination of water temperature, water pressure, and "off gassing" from the coffee will result in a beautifully mottled, earthy-colored, aromatic, structurally sound topcoat of bubbles on your espresso.
Crema serves as evidence of the emulsification process between coffee's oils and the water in which those oils are suspended. Therefore: Crema that is light likely means an under-extraction. An extremely dark or short-lived crema probably means over-extraction. And a bubbly, fragile crema may well mean the roasted beans were not given time to settle between roasting and brewing.
When evaluating espresso, it is essential not to lose sight of any of these three elements. While crema may be the obsession of the coffee community, the sweetness and lingering flavor of a good espresso, nobody really wants a shot that is only crema: you need the strident foundation of the heart and the fluid, blending properties of the body to make the crema worth savoring.
Also when evaluating espresso, it is essential to start with a decent espresso. Don't try an in-depth analysis of the coffee at Northgate's Barnes and Noble cafe... chances are, it won't work out quite in your favor.