Coffee extraction principle Coffee extraction method Coffee extraction course

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70% of coffee beans are water-insoluble fiber, and soluble flavors account for only 30% of the weight of cooked beans. The extraction rate of coffee powder is 18%-22%, and the coffee is the most delicious, that is, the so-called "gold extraction rate range".

The taste extracted when brewing coffee is not as good as it is when brewing coffee. If the soluble flavor substances which account for 30% of the weight of beans are extracted, there will be unpleasant bitterness, saltiness and throat bite if they are extracted too much. If only less than 18% of the soluble flavors are extracted, the extraction is insufficient, and it is easy to have inactive dead acid and half-unripe grain flavor and green taste, which makes the taste buds uncomfortable. Therefore, the extraction rate is too high or too low, indicating that the flavor extracted by brewing coffee is too much or too little, which will affect the taste of the coffee.

As far as coffee extraction is concerned, the rate at which flavor molecules are dissolved by hot water often varies with molecular weight and polarity. Basically, the lower the quality and the greater the polarity of the flavor, the faster the dissolution rate, on the contrary, the greater the mass and the lower the polarity, the slower the dissolution.

I do not know whether it is coincidental or interesting, shallow medium baking highlights the "fermentative effect" of sour aroma of flowers and fruits and grains in the early stage of Maillard reaction. Nuts and toast flavors with low molecular weight and high polarity are preferentially extracted by hot water. Therefore, if the extraction rate is less than 18%, that is, insufficient extraction, it will only dissolve flavors of lower quality and higher polarity, highlighting the inactive dead acidity, grain taste and astringency. Because the medium molecular weight flavor is too late to dissolve, it produces a very unbalanced flavor.

However, if the extraction rate is increased to the golden range of 18%-22%, the flavor molecules with medium molecular weight and moderate polarity, that is, the sweet aromas derived from the middle of Maillard reaction and caramelization, will be extracted immediately after the low molecular weight sour and grain flavors are extracted, cleverly neutralizing the dead acid and astringency of insufficient extraction, and reversing the extremely uneven taste spectrum.

However, once the extraction rate is higher than 22%, the insoluble bitter throat bites, that is, phenols and carbides with high molecular weight and low polarity, will be extracted, and the taste spectrum will be out of balance again. However, as long as the high molecular weight flavor is not excessive, it is not useless. If the extraction rate can be controlled within 22%, only a small amount of resin will be dissolved. Sweet, bitter and charred ingredients will help to balance the taste spectrum.

It can be said that the low molecular weight, medium molecular weight and high molecular weight flavor substances of coffee are difficult to dissolve and will be extracted in batches because of their high polarity. If the extraction intensity is not enough, it is easy to produce the taste spectrum of insufficient extraction, and if the extraction intensity is too high, it will produce the taste spectrum of excessive extraction. Studies have shown that the extraction rate is in the range of 18% to 22%, which is the most perfect extraction intensity. High-quality coffee aromas will be maximized in this "golden extraction rate range".