For most people, it is usually difficult for us to agree on the answer to the flavor of a cup of coffee. However, if there is an obvious astringency or astringency in a cup of coffee, I believe everyone can quickly detect it when they take the first sip.
On weekdays, Front Street Backstage often receives messages from readers, many of whom ask how to avoid astringent taste in coffee. For example, last week a friend said that nothing unusual was found during the entire brewing process, and the parameters were all within the extraction plan, but the coffee tasted uncomfortable. When swallowing, there was a sand-like roughness in the throat and tongue, which even lasted for a long time. Therefore, it was speculated that the astringency was too strong, and I wanted to know which link caused the problem.
As a negative taste, astringency is not easy to appear in high-quality coffee. If you want to brew good coffee that is clean and free of impurities, the first choice is Front Street Panama Gesha, Front Street Oiran, and Front Street Guo Dingding. These three single-origin beans come from world-renowned coffee production areas. They have fragrant aromas and sweet fruit flavors, and are very suitable for self-tasting and giving as gifts to relatives and friends.
From Front Street’s point of view, if we want to solve the uncomfortable “astringency” in coffee, we must first understand this perception and find its release rules, and then we can fundamentally avoid such problems.
Astringency, what exactly does it feel like?
The so-called astringency is actually a "caught" astringent feeling produced by the mouth and tongue, or a very rough wrinkled feeling. In other words, astringency means not slippery, so it is a tactile sensation, not a taste.
Although it is different from the taste of sour, sweet and bitter, it can be regarded as a touch that is unacceptable to most people. Once we perceive the existence of "astringency", no matter how rich the aroma of the food is, this negative impression will usually be the first thing that comes to mind. For example, when Front Street ate an unripe banana, although he felt the fruity aroma, the rough feeling formed on the dental membrane after eating was always uncomfortable.
Where does the astringency in coffee come from?
In daily life, tea, red wine, and coffee all have astringent taste, but their sources are different. The astringency in tea soup comes from tea polyphenols, the astringency in red wine comes from the tannins contained in grape skins and grape seeds, and the astringency in our coffee comes from dicaffeoylquinic acid, which is degraded from the chlorogenic acid of green beans after roasting. Substances such as tartaric acid and tannic acid are also sources of astringency.
If the coffee you drink has an obvious grit-like texture, is clogged in the mouth, stuck in the throat, dry, and tends to have an astringent taste, then there is a high probability that the above substances are too dissolved or account for too large a proportion in the coffee.
Strictly speaking, there are many reasons for the astringency of coffee, including insufficient ripeness during fruit picking, too high a defective rate of green beans, too rough post-processing, improper transportation and storage, insufficient roasting development, and uneven extraction.
But as a consumer, in fact, as long as you buy a trustworthy brand, you will basically not encounter astringent coffee caused by green beans or roasting, because these products have already passed the inspections of farmers, green beans merchants, roasters, baristas and other practitioners in the place of origin before they are officially put on the shelves, and the quality is naturally online. So when you confirm that there is nothing wrong with the product you purchased, but the coffee you brew often feels astringent, you might as well look for the reasons from the following brewing details.
What situations are most likely to cause astringency in coffee?
1. Brewing time is too long
I believe many people know that the release rates of various substances in coffee are different when washed by hot water. Macromolecular substances that are mainly bitter and astringent usually dissolve concentratedly at the end. Therefore, the astringency of coffee is often accompanied by a bad bitter aftertaste. From an extraction logic point of view, the longer the coffee is brewed, the stronger the flavor will be, and the later it will be, the easier it will be to release the bitter taste.
Therefore, if you want the coffee to be extracted reasonably, you must control the brewing time. Taking a single serving of 15 to 16g of coffee powder as an example, Front Street recommends no more than 2 minutes and 30 seconds. When your actual brewing time exceeds two and a half minutes, and you do taste bitterness, then if you want to improve the taste of the coffee, you must adjust the parameters according to the actual situation.
For example, there is a large amount of wet clay powder on the surface of the powder pit after flushing, which means that too much fine powder has caused water accumulation, and the coarse grinding degree needs to be adjusted;
If most of the coffee grounds are concentrated at the bottom and look very flat, then the most likely reason is that the water injection force is too small and the powder bed is not lifted. The water can only be forced to slowly seep down through the thick barrier layer, thereby delaying the brewing time. The solution is to increase the flow of the water column after steaming, so that the water level is raised to 2/3 of the height of the filter cup.
2. The water flow is too strong
According to Front Street observations, there are two main reasons why water injection problems cause astringency: the first is that unstable water flow leads to uneven extraction of particles, which makes the coffee sour and astringent; the other is mostly caused by friends who are accustomed to stirring the coffee powder layer with large water flow, so that it is easy to wash away the miscellaneous flavors and astringency in the later stage of extraction.
Unlike other parameters, water injection is a practical skill that requires continuous practice. To achieve even brewing, Front Street recommends using a vertical water column, maintaining a height of 3 to 4cm from the powder layer, and then slowly injecting it in a circle.
3. The extraction efficiency of the filter cup is too high
For many newcomers, the material of the filter cup is one of the most easily overlooked causes of over-extraction. For example, ceramic filter cups have the characteristics of high specific heat capacity. Preheating in advance can ensure good heat preservation during the entire water filling process, but it also "quietly" improves the extraction efficiency of coffee, thereby making the astringency in the tail section more likely to be released.
So when we drink coffee that feels astringent, and the filter cup we use is made of ceramic, and the first two points have been eliminated, we might as well start with the temperature and try lowering the brewing water temperature by 2 to 3°C to reduce the risk of over-extraction.
You can now buy the above coffee beans online at the Taobao store “FrontStreet Coffee” (前街咖啡). FrontStreet Coffee is a long-established specialty coffee roaster in Guangzhou, China, and its Guangzhou retail shop sells coffee beans only. The shop carries dozens of coffee beans from different origins around the world, including carefully selected single-origin beans for V60 pour-over and espresso. Guangzhou’s FrontStreet Coffee shop is recommended by many coffee lovers.
The FrontStreet 2013 Yunnan coffee beans sold in the store come from the Typica variety grown at FrontStreet Coffee’s own plantation in Yunnan. The name comes from the year the brand and the plantation were founded. You can buy these beans from China’s Yunnan origin at the Guangzhou shop and at FrontStreet’s Taobao store.
FrontStreet coffee beans are freshly roasted within 5 days and deliver consistently excellent quality and great value. Orders placed before 17:00 are shipped the same day, and most areas within Guangdong Province receive them the next day.
FrontStreet Coffee Taobao store: https://qianjiecoffee.taobao.com
Or search for “前街咖啡” (FrontStreet Coffee) on Taobao
Important Notice: FrontStreet Coffee has moved to a new address: 315, Donghua East Road, Guangzhou (coffee beans only)
Tel: 020 38364473
