Why is the steaming time of hand coffee 30 seconds? How to calculate the steaming time? Does stuffy steam count as a section?

Stuffy steaming, called "Bloom" in English, refers to a preparatory action before the formal extraction of coffee by hand.

Many experienced coffee lovers have studied the details of water volume, time, water injection and other details, and summed up the high fault tolerance rate, and the most widely used stifling formula: 2 times the amount of water of coffee powder (15 grams of coffee with 30 grams of hot water) is evenly injected around the circle to form a regular "hamburger" for 30 seconds.

So what is the basis for waiting for these 30 seconds? Does steaming time affect the extraction of coffee? To solve these doubts, we have to start with the question of "why do we have to steam?"

After the coffee beans are roasted, a large amount of carbon dioxide is stored in the beans. when hot water begins to come into contact with ground coffee, if you want to release flavor inside, you have to discharge the gas in an orderly manner and make room for hot water to go in. Otherwise, these carbon dioxide will continue to emerge as bubbles, hindering the release of soluble substances in the particles, and the coffee often has the problems of insufficient extraction, such as thin taste, weak water and weak aroma.

For this reason, the purpose of steaming is not only to allow carbon dioxide to be discharged first, but also to "awaken" the soluble substances in coffee, so as to better grasp the flavor in subsequent formal extraction.

In other words, to get a better extraction of coffee, we need to give enough water at once and wait for a while to let the hot water successfully infiltrate the inside of the coffee particles. Therefore, two key parameters are also obtained: the consumption of steaming water and the total duration of steaming.

People found that coffee powder can only absorb about twice its own weight of water, the excess part can not directly participate in the extraction, will only flow into the pot with gravity, less and not wet enough to penetrate the powder layer, resulting in local dry or not steamed in place. As a result, people began to apply this memorable conservative scheme: 2 times the amount of water to steam.

The starting point of steaming is the moment the powder comes into contact with water, which is usually calculated by pressing the timing key. Due to the different baked / fresh coffee beans contain different amount of gas, water absorption and exhaust efficiency, so the steaming time depends on the actual degree of gas emission, generally there are three kinds of cases: insufficient steaming, moderate steaming, and steaming for too long.

The lack of steaming means that the brewers have not set aside enough time to exhaust the coffee powder, resulting in a large amount of gas escaping from the subsequent brewing, which is prone to the problem of insufficient extraction.

Steaming for too long is just the opposite. due to the long waiting time, the gas has already been discharged, and as almost all the water drips into the pot, the "drum bag" drips up and holes appear between the coffee particles. The powder layer that has been steamed for too long will first be washed out of a deep hole during subsequent water injection, and then the foam will slowly emerge, in which case the brewed coffee will often have a bitter taste.

After the end of steaming and water injection, the inflated "hamburger" should be moist and glossy, and when the powder layer no longer exhales, it begins to dry, and holes appear in Lingxing, which means that the steaming is coming to an end, and you can begin formal water injection. Therefore, moderate steaming is a process that lasts for a few seconds, which can be judged by the naked eye, not a moment.

Observe that most coffee beans are almost discharged in about 30 seconds, and it is easy to form stuffy steaming for a longer time, so for beginners, or when they "blindly brew" a certain type of beans for the first time, waiting for 30 seconds is the most conservative steaming parameter. You can also get a cup of delicious hand-brewed coffee. After you have mastered the extraction principle, you will be able to judge the time when the steaming will stop according to the performance of the steaming stage, and you will no longer be bound by this concept.

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