Understand and identify the requirements of the perfect Espresso of Italian coffee

Look: the standard amount of a cup of perfect Single Espresso is to extract an ounce of coffee essence in 25 seconds.

Look at the appearance of Crema: a perfect Italian coffee espresso, the surface is always thick, brown red Krima crema, Krima crema is the protein, oil and other aromatic components extracted from the coffee under high pressure, is the essence of coffee concentrate. Perfect espresso, perfect Krima crema must be at least as thick as 4mm, and can't be broken by blowing gently. In the case of correct operation, if it becomes golden or even white, it means that the coffee has been kept for too long and expired; if you can repeat the duration of drinking after baking, it is a week of good preservation. The Krima crema floating on the surface can also judge the espresso operation, if the color is a little yellowish or white, the amount is very small, and the coffee flows out too fast, which indicates that the extraction pressure is too small and the extraction is insufficient, which requires finer grinding, tighter and more uniform filling pressure to increase the resistance of the coffee cake. If the color is too dark, the outflow is not coherent, or even drips out, which indicates that the extraction resistance is too high and the pressure is too high for the extraction transition, but for the whole cake, it is not enough extraction, which is caused by too fine powder, too tight powder and too much powder.

Smell: the perfect espresso should have a pleasant aroma and should never have a charred taste. If there is a charred taste, it is a pity that what you drink is a cup of over-extracted espresso.

Product: the perfect espresso should be thick, the taste will not be simply bitter, it may have a bitter taste but a combination of aromatic or sour taste, which is mainly related to the blending of coffee beans.