Introduction to the method of time parameters of steaming water quantity of hand-brewed coffee

A few days ago, when sharing the problem of coffee exhaust, the street also roughly said that "carbon dioxide in coffee beans" inhibits the release of volatile flavor substances from coffee ", so there will be a" steaming "step when brewing. That is, by injecting a small amount of water to wet the coffee powder, let the coffee powder exhaust gas quickly, in this process, the coffee powder will expand, forming a bulging shape.

If the coffee beans run out of gas, then when steaming, the coffee powder will have no gas to drain, so it will not expand. Therefore, it is generally believed that the steaming coffee does not expand on behalf of the stale, the loss of flavor. On this issue, Qianjie believes that the expansion of coffee can be used as a reference for the freshness of coffee beans, but we should not rely too much on this method, because there are other reasons why the coffee powder layer does not expand. -baking degree I don't know if you have noticed that those bulging "hamburgers" are deeply roasted coffee beans. This is because the deeper the roasting, the larger the size of the coffee beans and the looser the internal structure. On the one hand, carbon dioxide gas will be more abundant, on the other hand, the loose structure is more prone to water expansion. So we can see the perfect "hamburger" drum bag in brewing deep-roasted coffee. In contrast, the lighter the roasting, the harder the texture of the coffee beans and the less carbon dioxide in the body than the deep-roasted coffee beans. So the "hamburger" bulging during steaming will be relatively small, and sometimes there will be no obvious expansion characteristics.

For example, when high-altitude Rosa coffee beans are brewed 2 weeks after the baking date, the coffee powder layer does not expand obviously, this is because the lightly roasted Rosa coffee beans are harder and the gas is released more slowly, and because they are lightly roasted, there is not too much gas, so during the long steaming time of 30 seconds, sometimes only slightly bulging packets are seen, and sometimes there is no expansion. Sometimes a large bubble is spit out in a flat layer of powder. This does not mean that it is not fresh and does not affect the flavor of Rosa coffee.

In another example, a friend once brought a bag of very lightly roasted coffee beans to share with the front street, and the sound of the bean grinder felt very hard during grinding. The same steaming time when the powder layer does not expand, brewing out of the coffee acidity is very bright and pleasant, and does not have the flavor of the stale beans. The size of the coffee drum is also related to the degree of grinding. if the degree of grinding is relatively fine, then it is not easy for the gas to find a gap to "slip" out, and the gas will prop up the coffee powder to find more space to "slip" out. If there is continuous rapid gas discharge, there will be large bubbles.

On the other hand, if the grinding degree is rough enough, there is enough space in the gap between the particles to let the gas out, so that the powder layer will not expand.

So, if you want to see Meimei's steamed hamburger, choose deep-baked coffee beans and grind them.