Teach you to judge a good Espresso

People like to drink coffee because it releases flavor and aroma when it is brewed. The sources of flavor in coffee are mostly water-soluble, such as caffeine, protein, sugar and so on, while the sources of aroma are mostly insoluble, such as coffee oil. The volatile aroma of coffee oil is found in roasted coffee cells. Some of these oils are insoluble in water and only emulsify 10% when using an Espresso machine at high temperature and high pressure and float in the hot coffee juice, turning into a rich ochre red Crema. We can judge the quality of a cup of Espresso by the color, thickness, markings and other appearance of Krima.

The thickness and rhyme of Espresso

Espresso coffee tastes particularly thick, and its consistency comes from the fact that when the water flows through the coffee powder to the cup, the carbon dioxide bubbles are suspended in the coffee juice liquid and mixed with an emulsified gel. These gelatinous substances inhibit the taste buds' sense of bitterness, making us feel particularly fragrant and strong when drinking Espresso coffee, but not too bitter. These mixed colloidal substances and emulsified oils become tiny droplets and are responsible for the so-called "rhyme", that is, by reducing the surface tension of the liquid. At the same time, the gel makes the tiny oil droplets penetrate the taste buds deeper, making the oil stay, and then slowly release the aromatic substances attached to it. This aroma can let the olfactory senses know the aroma and throat rhyme for up to 20 minutes after drinking Espresso coffee.