Hand flushing skills-the necessity and adjustment of steaming, do you know how to calculate the time of hand steaming?

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In the process of learning hand flushing, in addition to knowing the conventional round water injection method and water cut-off method, the most common term asked by many students is "steaming" and put forward various strange statements. I think it is necessary to write an explanation about it to explain one or two.

First of all, we all know that coffee beans will continue to emit carbon dioxide and volatile aromatic substances after roasting. Whether coffee beans are used for semantic expression or hand flushing today, carbon dioxide must be fully emitted to avoid being hindered by exhaust in the extraction process, thus making the front extraction incomplete (insufficient extraction). In order to make the follow-up hot water extract the soluble substances in coffee smoothly, steaming is very important!

A small amount of hot water is used to trigger the emission of carbon dioxide from the ground coffee particles as quickly as possible, so that the hot water can smoothly enter the gap between the coffee particles, take out all kinds of soluble substances, and dissolve and hydrolyze.

For hand flushing, steaming is particularly important without the help of 9 bar atmospheric pressure of the Italian coffee machine to help you get a better extraction ratio in the front stage of extraction.

Then a student asked, if I am not stuffy and steaming, can I make the extraction return to the normal proportion for a longer time? theoretically, yes, but it also prolongs the brewing time, enhances the concentration of the coffee and dissolves more chlorogenic acid, quinic acid and other substances, causing the coffee to become sharp and astringent.

So what do you need to pay attention to in steaming?

First of all, there is' water'. Today, we apply a small amount of hot water to discharge carbon dioxide, so the amount of water can be controlled to 2 times the weight of coffee powder, for example, 20 grams of coffee powder. We can use the amount of water between 20 and 40 grams to do steaming.

Then there is the 'time', which depends on the depth of roasting and the length of storage of coffee beans. Generally speaking, the roasting degree of coffee that is often used to make coffee by hand is the shallow and medium roasting in the mouth of consumers, which is about 75 Agtron 60%. When carbon dioxide emissions are stable, it is about a week after baking. The longer you put it, the more carbon dioxide will escape, and after about the fourth week, the carbon dioxide emissions will become thinner. When students and consumers are brewing, if they use 2 Murray coffee beans within 4 weeks, the steaming time is about 20 Murray and 30 seconds after water injection, and then they can continue to inject water to complete the brewing process.

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But what if you encounter coffee beans that have been stored for a long time?

Under normal circumstances, fresh coffee particles will cause the coffee powder bed to rise up into a hill because of exhaust, and if it is stored for a long time, it will rise slightly or not at all. At this time, you should pay attention to that your steaming time should not be too long, and the steaming time should be halved. If you steam in accordance with the time of 20 murals and 30 seconds, it will make the coffee powder bed gelate. As a result, the second water injection can not be extracted smoothly or even because the water can not pass through the powder bed, the water flow directly through the filter paper, the astringent taste of coffee products becomes very obvious, and the concentration is low, the taste will become light and sour.

I hope that through this article, we can understand the necessity of hand steaming and adjust the steaming time according to the storage time of coffee. I wish you all can enjoy a cup of delicious hand-brewed coffee every day.