A friend asked Qianjie, "Qianjie Qianjie, I brewed coffee according to the brewing method you suggested, but it felt astringent when I drank it, what happened?" "I believe that many friends have also encountered it when making coffee, and they didn't notice anything unusual in the whole process of brewing coffee, but the coffee brewed out has an astringent feeling and is not very comfortable. Let's go down to the front street to analyze what causes such a phenomenon when brewing.
What is astringency? We feel astringent when we drink coffee, which is an uncomfortable sensation on the palate and has nothing to do with the taste. It is mainly caused by polyphenols (chlorogenic acid, tannins) in coffee. If the coffee you drink is rough, gritty, and dry, then it is possible that the amount of chlorogenic acid and tannic acid in your coffee is too large or too large.
What are the conditions for astringency when brewing?
- Brewing for too longThe longer the coffee is brewed, the more bitter it becomes, because the release rate of coffee substances is different, and when brewing coffee, acids are the easiest to extract at first, followed by sweets, and then bitters. Only the longer the brewing time, the more bitter substances will be released. Chlorogenic acid and tannic acid belong to these bitter substances. Therefore, if you want the coffee to not appear bitter and astringent, you must control the extraction time, such as brewing a one-serving (15g) of coffee, Qianjie recommends not more than 2 minutes and 30 seconds. If you exceed this time in the actual brew and do get astringency, then you need to adjust the parameters, such as adjusting the grind or the number of water fills.
-The water temperature is too high, and tannic acid is easily releasedHigh water temperature can brew out more natural substances from coffee, but water does not distinguish between what tastes good and which is bad. Therefore, high water temperatures can sometimes bring out the best flavor of a certain coffee, but it also increases the risk of bitterness and astringency. Front Street Coffee generally does not recommend brewing coffee with a water temperature higher than 93. When brewing light roast coffee, Front Street generally uses 91 for brewing, which is a relatively safe temperature. - Water injection techniqueThis is the reason why it is easier to flush out the astringency. Because water injection is a practical class, there is no skill to speak of, and it requires constant practice. The suggested way to fill the water in Front Street is to fill the water column vertically, slowly fill the water in a circle, and rinse the coffee powder layer as much as possible.
Some friends flush out the astringency, which may be because they do not inject water evenly when filling water, resulting in uneven extraction between the layers of coffee powder, and it is easy to have a sour and astringent feeling. Or some friends like to stir the coffee powder layer with a large stream of water, which is also prone to miscellaneous flavors and astringency. Because stirring the ground coffee layer is also a way to improve the efficiency of caffeine, it is also easy to risk over-extraction.
- Water quality
Eventually, Front Street found out the reason for the astringency of the friend's coffee, and it turned out that the water he used to make coffee was directly from the faucet.
If you want to brew a cup of delicious coffee, there are also requirements for water quality, generally suitable for coffee water TDS is 75-250ppm, an appropriate amount of calcium and magnesium ions help the extraction of coffee, but too much calcium and magnesium ions will hinder the extraction of coffee flavor substances, and the water containing more minerals itself tastes bad, the taste of water with more magnesium ions is bitter, and the taste of water with more calcium ions is slightly astringent. Tap water is generally high in impurities, and the brewed coffee will appear bitter and astringent. 
Therefore, for the water used to make coffee, at least it is also brewed with drinking water filtered by filter.
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