The nutritious and delicious ingredients in espresso coffee and standard espresso coffee beans can be divided into two categories: A and B. Class A substances are easily soluble in water, but easy to decompose and deteriorate at high temperature. Class b substances are insoluble in water. Usually, people make coffee by filtering or cooking. It's called triangle coffee. The filtered coffee only contains class B substances, but these methods can't get all the effective components of coffee. It has always been characterized by a light but impure taste. /kloc-At the end of 0/9, Italians accumulated hundreds of years of experience in coffee making and drinking, and finally solved this problem technically and made espresso. Since then, this more fragrant, stronger, more nutritious and more artistic espresso has swept the whole of Europe. "ESPRESSO" originally meant "fast". Refers to the instant extraction of espresso. The key technology of espresso production lies in the boiler in the coffee machine. This specially designed small boiler produces water at 90 degrees Celsius and high-pressure steam at 1 10 degrees Celsius. When water and steam pass through the molded coffee powder, the water at 90℃ will dissolve out Class A substances, which will not decompose or deteriorate, and the high-pressure steam at 1 10℃ will extract Class B substances (the golden natural oil on the surface of espresso coffee is one of them). The caffeine content of espresso is very low, only 1/3 of other coffee varieties. To make espresso, 7 grams of fried and finely ground coffee powder and 2 ounces of water are used. The espresso after making is only 65,438+0 ounces (coffee powder absorbs 65,438+0 ounces). Because if the machine works too long, the coffee will become bitter. The most important sign of a good cup of espresso is its emulsification. The emulsion should be uniform, only golden yellow and 5 mm thick. And can keep 1.5-3 for three minutes or more, and will not spread out. When you drink coffee, it will cover the cup wall like syrup. You should use a special espresso coffee cup carefully and heat the cup in advance. Making cappuccino At the beginning of the 20th century, Italian Archie Garcia invented the steam pressure coffee machine and developed the cappuccino. Cappuccino coffee is made by adding steamed milk to espresso, the foam is higher than the mouth of the cup, and some chocolate powder, coffee powder or cinnamon powder can also be sprinkled on it. At this time, the color of coffee, just like the monks in cappuccino church put a headscarf on their dark brown coats, gave the name coffee. Pour the prepared espresso into the cup and prepare the milk. It is best to have high quality milk. Use cold milk, because the foam is better, the foam lasts longer and the taste is fresher. Pour the milk into a stainless steel tank with good heat conduction so that the nozzle is just below the surface of the milk. Don't turn the switch too big, but don't turn it too small. Rich small bubbles are ideal. Gently put the foam on the coffee with a spoon and pour in the remaining milk. Chocolate powder can prevent boiled milk from forming milk skin and make milk more delicious.