Why is the extraction time of hand-brewed coffee and Italian coffee so important?

When many Xiaobai friends first come into contact with coffee, they will pay great attention to grinding, powder water ratio, water temperature, techniques and other controllable things related to production, only "time", this uncontrollable factor is easy to be ignored by everyone, but in fact, it is very important for the production of a good cup of coffee.

The soluble substances in coffee beans we need to talk about the soluble substances in coffee beans first. In a coffee bean, it has only 30% of the soluble flavor, and the remaining 70% is insoluble wood fiber. On the same principle as chewing gum, when you finish extracting its soluble flavor, it will become tasteless "wood dregs"! Although there are 30% soluble flavor substances, we don't need to extract them all! We only need to extract 18-22%.

The soluble flavor substances of coffee beans can be divided into three kinds: sour substances, sweet substances and bitter substances. Each substance has a different dissolution rate, which means that each substance has a peak of mass release in a different period of time.

The dissolution rate of sour substances is the fastest, so it will reach a peak at the beginning of extraction and be released in large quantities! The second is the sweet substance, the dissolution rate of the sweet substance will be slightly slower than that of the sour substance, so when the sour substance is released in large quantities, it only dissolves little by little, and only in the middle of the extraction does it begin its peak period, dissolving in large quantities. The rate of dissolution of bitter substances is the slowest, from the picture, we can see that the initial bitter substances are almost parallel to the horizontal line of the table, very slowly, until the sweet and sour substances reach the release peak, it begins to slowly increase the rate of dissolution! So, generally speaking, the longer the extraction time, the more dissolved substances, and the final coffee flavor will be richer and more distinct!

And the reason why we should pay attention to time is to control the amount of these substances released! To ensure the balance of taste. For example, when the extraction time is too short to involve the nodes where a large amount of sweetness is released, the whole cup of coffee will become thin and sour without the support of sweet and bitter taste, forming a state of "insufficient extraction"; and if the extraction is followed by the release of a large amount of bitterness, bitterness will dominate, and the whole cup of coffee will be immersed in the bitter negative taste, which will form a "excessive extraction"!

Therefore, we need to stop the extraction of soluble substances after the release of a large amount of sweetness and before the release of a large amount of bitterness, so that we can get a cup of coffee with a balance between sweet and sour.

And the best way is to control the time, hand coffee to 15g beans as an example, in the normal parameters, only need to control the extraction time in the range of 1 minute 50 seconds ~ 2 minutes 25 seconds, you can get a cup of sour, sweet and bitter balanced coffee!

The topic of key misunderstanding is over, let's say one more key misunderstanding, this is about the release of sour, sweet and bitter substances! The sour, sweet and bitter substances we mentioned above are often thought to be released sequentially! But in fact, sweet, sour and bitter substances are released at the same time at the beginning, but because of their different dissolution rates, there are different peak dissolution nodes, which is the misunderstanding.

Just like when we drink coffee obtained by shallow baked bean extract, although it is difficult to feel the bitter taste, the bitter substance exists, but because its quantity is relatively small, it is covered up by sour and sweet substances!

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