Why is coffee steamed?| How to judge the situation of coffee steaming| How long is the steaming time?

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The so-called steaming is the pre-operation of soaking the coffee powder with a small amount of hot water before making the coffee. Roasted coffee beans gradually emit carbon dioxide through small holes in the surface. this process is called awakening or ripening, and the emission rate varies according to the degree of baking, and the exhaust slows down as time goes on. Steaming grasps the moment when hot water comes into contact with the powder to let the gas out quickly.

This seemingly simple small action has a great impact on the finished product. After grinding the coffee powder, the surface area of contact with the outside world increases greatly, and the gas begins to emit. These gases will form an isolation layer between hot water and powder and cannot be extracted effectively. And carbon dioxide dissolved in water will have a sour taste, resulting in a bad taste. Infiltration makes the temperature rise and the gas expels upward, causing the surface of coffee powder to protrude and expand as a whole. some people say that the degree of protuberance on the surface of coffee powder represents the freshness of coffee, but no matter whether it is formed or not and its size, the point is whether the purpose of this action can be achieved.

The key point of steaming is to release the gas that will interfere with the manual extraction first, so as to make the extraction process more smoothly.

In addition to exhaust, steaming takes away the gas while hot water fills the hole, and the contact between the powder and hot water makes the aroma disperse. in addition, the powder expands and expands the distance between them, and the circulating gas promotes the stretch. opening the pores between the powders makes it easier for water to pass through, which is helpful for subsequent water flow control. these are the associated effects of exhaust gas.

There are two purposes of steaming:

First:

In order to release the gas in the coffee particles, it is mainly carbon dioxide. Generally speaking, the closer it is to the baking time, the more bubbles usually occur during prepreg. On the other hand, the coffee beans with deeper roasting degree will release more gas in the steaming process than the coffee beans with lower roasting degree because of less water content.

Second:

If the coffee particles after exhaust gas can be evenly absorbed and saturated, the subsequent extraction can be uniform. In short, during steaming, the air between the coffee powder particles expands and releases a large amount of carbon dioxide, while a short gap layer between the coffee powder particles will provide the space needed for hot water to pass through the powder layer during formal water injection.

Now you know why hand-made coffee is steaming.

Qianjie Coffee wants to tell you that steaming is not just waiting for time to pass blindly. In fact, it should be steamed according to the freshness of the beans. The more fresh the beans are, the longer the steaming time can be; the longer the beans are baked, then the steaming time can be shortened or even not steamed.

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