What is the purpose of steaming hand coffee in the process of making coffee?

Stewing and steaming mainly allows hot water to seep into the cell wall of coffee fiber, forcing out the gas inside, making the water-soluble flavor more easily extracted by hot water.

Stewing time generally depends on the baking degree, the shallower the baking, the harder the fiber, the less easy to extract, and the steaming time can be extended. The deeper the baking degree is, the softer the fiber is, the easier it is to extract, and the steaming time should be reduced, even without steaming.

Usually stewing will increase the extraction rate and coffee concentration, so the length of stewing should be determined according to different beans, roasting degree and individual taste.