Crema, the natural golden froth that graces the surface of a well-made tazzina of straight espresso, is an almost mystical obsession among Italian espresso lovers. Its only practical role is to help hold in some of the aroma until the coffee is drunk, but its cultural connotations are legion.
For Italian espresso professionals it is the key to diagnosing the coffee underneath. Dark-colored crema indicates a blend heavy with robusta coffees. Golden-colored crema reveals a blend based on higher-quality arabica coffees. Crema made up of a few, large bubbles indicates a coffee that has been brewed too quickly and is probably thin-bodied. Dense, clotted crema indicates a coffee that has been brewed too slowly and may be burned.
So, above all, if your espresso tastes good but has little crema, enjoy the coffee first and worry about how it looks later. Given that advice, here are a few steps to take if you continue to be concerned about crema-less espresso.
Resign Yourself if You Are Using a Steam-Pressure-Only Brewer. If you are using a brewer that makes use of the pressure of trapped steam alone to press the brewing water through the coffee, either give up on crema or buy a pump machine. Because, even if you follow the manufacturer’s instructions for brewing, you will generate only a little crema. Steam-pressure-only brewers will produce reasonably good espresso drinks with milk, but will not produce a straight espresso with the richness and body, or the crema, of the caffe product.
Good Technique. If you are using a pump or piston machine (categories 3 and 4, pages PPP-PPP), begin your pursuit of crema by reviewing your brewing technique against the instructions on pages PPP-PPP. Make certain your grind is a fine grit, that you use sufficient coffee, that the coffee is evenly distributed in the filter, and that it has been tamped hard, with a twisting motion of the tamper, to polish the surface of the dose.
Precision Grind. Above all, review the grind of your coffee. It should be a very fine grit, but also a uniform grit, produced either by a large, commercial grinder in a store, or by a specialized home espresso grinder.
Fresh Coffee. Make certain your coffee is fresh. If you buy whole bean coffee in bulk, buy it from a vendor who emphasizes freshness, keep it in a sealed container in a cool, dry place, and grind it as close to the moment of brewing as possible. If you use pre-ground, canned coffee, buy it in smaller, half-sized cans, open the can just before brewing, and immediately transfer the excess coffee to a sealed container for storage.
Lots of Coffee. This may qualify as cheating, but often the only way to achieve good crema on some pump machines is by using more than the recommended amount of coffee per serving. The normal recommended dose of ground coffee per shot of espresso is slightly less than two level tablespoons. For better crema use the double filterbasket rather than the single and use at least half-again as much coffee per serving, or about three level tablespoons.
Small, Pre-Warmed Cup. Brew directly into a narrow-sided, three-ounce demitasse cup that has been pre-warmed. The warm, narrow cup will help build up and hold the crema.