Do you know what the steaming of hand-brewed coffee is? | what is the function of steaming coffee?

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Stuffy steaming can see the reason for the use of fresh coffee powder, fresh powder after the awakening stage to discharge most of the gas after the activity is high, can make steaming play a good effect and lead to good coffee. Steaming is like an alarm clock to wake up coffee beans. "A good beginning is half done" is very suitable for steaming. Whether you can make the coffee powder live depends on the first half a minute.

What is steaming?

Stuffy steam

Bloom, the so-called steaming, is the pre-operation of soaking coffee powder with a small amount of hot water before making 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.

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.

If the initial step of hand flushing is less steaming, a large amount of hot water will follow a local and a small number of waterways through the powder layer, so that the dripping time will be longer, which may lead to excessive extraction, because the extraction time is longer and more substances are dissolved. the taste may be more sour and irritating, or full of miscellaneous taste. However, once you can pay attention to the action of steaming and then start formal water injection, the hot water can pass through the filter layer evenly composed of coffee powder, and then achieve the purpose of uniform extraction.

The role of steaming

In an ideal steaming process, the coffee powder will slowly expand in the presence of hot water, as if the coffee powder keeps pushing the hot water to the top. At this time, the surface tension of the water and the pressure caused by the carbon dioxide released by the coffee powder add up to the gravitational acceleration of slightly larger water and the downward pulling force caused by capillarity.

The best end time of steaming will be the sum of the surface tension of water and the pressure produced by carbon dioxide released by coffee powder when the expansion reaches the limit, which is slightly equal to the downward pulling force and stable water injection speed caused by the gravity acceleration of water and capillarity. at this time, the void layer in front of the coffee powder particles has not yet collapsed, so it is a good time to start the first water injection. Although the longer steaming time may get a thicker taste, it is also easy to affect the cooking results because of the larger surface area in contact with the air and the rapid decrease of water temperature.

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