The importance of grinding and extraction in coffee

Where a cup of espresso comes from, high-quality coffee beans are very important, and the degree of grinding of coffee powder is also very important. The degree of grinding of coffee powder will greatly change the taste of coffee, the taste of coffee will become silky, or the taste will become bitter. The effect of grinding degree on coffee taste is mainly in three aspects: contact time between coffee powder and water, extraction rate and flow velocity. [contact time between coffee powder and water]

Contact time is the total duration of contact between water and coffee powder. Take French coffee and espresso, for example, the contact time between the two is thousands of miles away. If the water is in contact with the coffee powder for a long time, the coffee powder needs to be ground thicker; if the contact time is long and the coffee powder is ground very fine, the coffee will be over-extracted, losing its aroma and leaving only a bitter taste. And vice versa, if the contact time is very short and the coffee powder is ground very coarse, the coffee will become insipid and tasteless. Find the balance between grinding and contact time, and you can make really good coffee. [contact time and extraction rate of coffee]

It sounds complicated, but it's really easy to understand. The extraction rate is the total amount of soluble substances extracted by water from coffee. If the extraction is not enough and the content of soluble substances is too low, the coffee will become very sour or lack sweetness. If it is scientifically explained that acid and salt dissolve faster than sugar, coffee lacks sweetness because the sugar in the coffee does not have time to dissolve, and excessive extraction will give the coffee a charred taste. Only by correctly controlling the grinding degree and contact time can the ideal extraction rate be obtained and the coffee will become more delicious and fragrant.

[finally, let's talk about the velocity of the current]

The finer the coffee powder, the slower the flow of water. The slower the flow rate, the longer the extraction process and the more fully the coffee flavor is extracted. In addition, water usually flows along the path with less resistance, so the uniformity and uniformity of grinding are very important. If the grinding is uneven, the distribution of water flow will be uneven, resulting in uneven extraction. Water flow is also an important basis for judging whether the grinding degree is appropriate or not. If the flow rate is too fast, it means that the coffee powder is too coarse, and the coffee taste will be too insipid; but if the flow rate is too slow, or if there are deposits at the bottom of the cup, it means that the coffee powder is too fine, the coffee taste is too heavy, and the taste is too bitter.

Making delicious and fragrant coffee is an art as well as a science. The choice of coffee beans, the degree of grinding of coffee powder, and even the use of what kind of water quality is also very particular, this may be the charm of coffee, carefully cook a cup of strong coffee, slowly taste, must have a different taste.

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