What are the manifestations of insufficient and over-extraction of coffee? How to avoid over-extraction or deficiency of hand-brewed coffee

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A few days ago when chatting with friends talked about extraction. When it comes to extraction, it is inseparable from two situations that make many coffee people feel melancholy_insufficient extraction and excessive extraction. What is the difference between these two situations? How can we improve it when we're washing it?

extraction

First of all, let's figure out what extraction is!

Coffee extraction is a process in which water passes through the coffee powder bed and brings out the substances in the coffee. In this process, we need to pay attention to a lot of things, water temperature, grinding, water supply, stirring, etc., any of which parameters will affect the extraction of a cup of coffee. The extraction of coffee is generally divided into: insufficient extraction, gold cup extraction and excessive extraction.

Gold cup extraction

The so-called gold cup extraction means that when you brew coffee with a concentration of 1.2--1.4 TDS and an extraction rate of 18%--22%, it is considered to be in the ideal extraction range. Anything less than this is what we call under-extraction, and anything more than that is over-extraction.

Under extraction & over extraction

Insufficient extraction means that the substances brought out by the water are not enough, and there are still many extractable substances in the coffee powder. At this time, the coffee tastes sour, sweet and salty, and the taste is thin. The aftertaste is not long.

This is because in the extraction process, acid and salt are extracted first, followed by sweet and bitter. Because the extracted substance is not enough to neutralize the acid extracted in the previous paragraph, the acid of the whole cup of coffee makes people feel too stimulated and unbalanced.

overextraction

The soluble content in coffee is 30%, but the maximum we need is only 20%, and more than this 20% is over-extracted. Because of the excessive amount of substances extracted, this makes this cup of coffee with a distinct bitter, miscellaneous and astringent taste.

So how do we adjust?

Take Yemen Mocha as an example:

1, water temperature 89℃, powder water ratio 1:15, BG bean grinder 6W (China standard 20 sieve pass rate 35%), brewing time is 1 43". The mouth has some irritating acid, thin taste, and a "watery feeling".

Xiao Bian thought this was a phenomenon of insufficient extraction, so he adjusted the grinding and ground some.

2, water temperature 89℃, powder water ratio 1:15, BG grinder 5B (Chinese standard 20 sieve pass rate 70-75%), brewing time is 2 20". The palate is rich in dark chocolate, caramel sweetness, but with some rubbery and woody notes.

Although the brewing this time did not have a sharp acid, but also came out caramel sweet and dark chocolate flavor, but at the same time there are some bad taste, such as wood, rubber, and drink a kind of astringent feeling, drink like wrapped in gauze. Therefore, Xiaobian thinks this is over-extraction, so he will grind slightly thicker.

3, water temperature 89℃, powder water ratio 1:15, BG grinder 5R (China standard 20 sieve pass rate 60%), brewing time is 206 ". The entrance is more rounded grape-like acid tone, the middle has a dark chocolate-like bitter sweet, caramel back sweet is also quite lasting!

Different grinding degrees in the extraction of the extraction rate are not the same, coarse grinding, extraction rate decreased, so the extraction is insufficient; and grinding too fine, extraction rate increased, it is easy to over-extract. Of course, the influence of water temperature is also there, the water temperature is low, the extraction rate is naturally low; and the water temperature is too high, the extraction rate is also improved.

If you want to find out the reasons that affect your coffee flavor, Xiaobian suggests that you can record the data every time you brew, and only change one parameter at a time when adjusting the parameters!