In search of a perfect cup

摘要

Look into a small, elegant cup of espresso coffee and examine carefully the top layer of foam, known to aficionados as crema. Made of tiny gas bubbles trapped in a liquid film, the foam seals the coffee's intense aromas and flavours and locks in heat. A good cremo depends on the quality of the coffee and on the skill with which it is prepared. In a perfect espresso it is velvety, with a warm and characteristic hazel-brown or "tiger-skin" colour. It is also persistent, lasting as long as the drink, and with sufficient body to support the weight of granulated sugar for a few seconds. Perfect espresso is the ultimate coffee. It ranks with fine wine for the complexity of its chemistry. Unlike wine, however, it does not improve with age. "Espresso" means prepared on the spur of the moment, and it has become the trademark of rich, intense coffee that must also be consumed at once. Its taste is so dense, though, that it can remain in the mouth for up to half an hour after drinking.