Why does the hand steam do not swell? Why should hand-made coffee be steamed?

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Recently, fans often ask the editor why his stuffy steam can't get a "hamburger". Have you been cheated by the store to buy stale beans? Well, it's true that the freshness of beans will affect steamed hamburgers, but it's not the only reason! The editor is going to talk to you today about what factors will affect the steaming "hamburger" of hand-brewed coffee.

Before we do that, let's take a look at what steaming is.

Steaming, which is often expressed as Bloom in English, refers to the preparatory action of wetting a small amount of hot water evenly on the surface of coffee powder before formal water injection during hand washing.

Steaming is mainly to release the gas in the coffee particles, mainly carbon dioxide. Generally speaking, the closer you are to the baking time, the more bubbles you will bubble when steaming. On the other hand, the coffee beans with deeper roasting degree will release more gas in the steaming process than the coffee beans with shallow roasting degree because of less water content. If the coffee particles discharged from the gas can be evenly absorbed and saturated, the subsequent extraction will 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.

Factors affecting the bulging "hamburger"

1. The baking degree of beans

Right! The roasting degree of coffee beans will also affect the "hamburger" that bulges when steaming. Generally speaking, light-roasted coffee beans do not bulge a very good-looking "hamburger" like deep-roasted coffee beans, but are relatively gentle. This is because the more carbon dioxide is contained in the more roasted coffee beans, the more exuberant the exhaust, so it is easier to bulge when steaming. And vice versa, light baked beans, even if they are very fresh, may not necessarily achieve the "bulging" hamburger effect you remember.

2. The freshness of beans

As mentioned earlier, steaming is for exhaust, so the fresh coffee beans contain more gas (mainly carbon dioxide), and the more "hamburgers" swell when steaming naturally. If you don't see an expanding "hamburger" during stewing, it means that the coffee may have been roasted for too long, causing the carbon dioxide in the cells inside the beans to be released naturally, which means that the beans are no longer fresh.

3. The grinding thickness of coffee powder

In addition, if your grinding is too rough, the surface area of water in contact with coffee powder will be small, and the exhaust effect will naturally be weak. if the grinding degree is particularly rough, there will be no "hamburger" anyway. Because as soon as the water pours down, it flows directly through the gap between the coffee powder, not even steaming, let alone a "hamburger".

4. Steaming capacity

If the water supply is too much, the water will flow directly, it is difficult to play the role of steaming, and because it is not fully steamed and the extraction is insufficient, in fact, it only plays the role of diluting the coffee liquid. So we usually use one to two times the amount of powder to steam.

And why does a well-bulged "hamburger" always collapse quickly? There are three reasons:

1. Oversteaming

2. Excessive water injection after steaming.

3. Bean baking is relatively shallow.

It collapses soon after steaming a hamburger, which should be related to the technique, such as strong water injection to break the powder layer or too much water injection. Steaming and injecting water is best to draw a circle from the center; when steaming, the amount of water is too little, the coffee powder at the bottom and edge of the filter cup is still dry, and when reinjecting water, it is especially easy to produce large "volcanic bubbles" when it is hot.

The "hamburger" bulging during steaming is also affected by many factors ~ so when you don't see the powder bed bulging during cooking, don't think that the beans are not fresh or the baking degree is not deep. Or is it a rough grinding? There are many influencing factors in coffee.