Water quantity of hand-brewed coffee-water output adjustment of coffee machine

Water quantity of hand-brewed coffee-water output adjustment of coffee machine

First: release the gas in the coffee particles, 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.

The inside of the coffee powder is similar to the honeycomb structure, with numerous penetrating holes. The freshly roasted coffee beans will continue to emit carbon dioxide, much of which will be stored in the holes in the coffee beans at the beginning.

If hot water is poured directly and at a high speed on such a coffee powder, the hot water will be extracted close to the periphery of the coffee powder, and the internal carbon dioxide will be blocked by water and cannot be removed. And because there is carbon dioxide in the powder, the hot water can not seep into the coffee powder. Therefore, hot water will only constantly wash the surface of coffee powder, resulting in excessive extraction on the surface of coffee powder, but no extraction on the inside.

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 local and a small number of waterways through the powder layer, so that the filtration time will be prolonged, which may lead to the result of over-extraction.

However, once you can pay attention to the steaming process 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 following points will be conducive to the smooth achievement of steaming:

1. Before steaming, make sure the coffee powder is as horizontal as possible in the filter screen or filter paper.

2. When steaming, the force of water injection is not too strong, gently.

3. The best amount of water for steaming is 10% of the total water. For 240 milliliters of coffee, the amount of water needed for steaming is about 24 milliliters.

4. in the process of steaming, the amount of extract flowing is as little as possible; when there is too much extract in the kettle, the amount of water injected should be reduced, or attention should be paid to the degree of grinding.

5. The steaming time is about 30 seconds to 55 seconds. When the expansion of the coffee powder surface is over and the surface is about to shrink, it means that the steaming is complete and the first water injection can be started.