Coffee bean knowledge: espresso beans

Espresso beans take longer to bake than regular beans, so the oil in the beans floats to the surface of the beans. Although Arabica coffee beans are generally believed to be the best in terms of flavor, acidity and bitterness, it is still unclear how to choose the best type of coffee beans. Although robusta beans are generally thought to be of poor quality, they produce more foam (a layer of red and golden foam floating on the surface of the perfect espresso) and are an excellent complement to Arabica beans.

Without foam, espresso is just a kind of thick, strong coffee. Foam can also reduce the rate at which volatile oil is released into the air after brewing, thus creating the unique aroma of espresso.

To make the best espresso, use the freshest beans. Stale coffee beans look very greasy and give off a moldy smell. Coffee beans should be kept in a sealed container and placed in a cool, dry place. Coffee beans cannot be stored in the refrigerator because that will accumulate moisture and destroy the porous structure of coffee beans, thus reducing the quality of flavor.

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