Why is hand-brewed coffee astringent? The roasting degree of coffee beans causes the sour and astringent taste of coffee.

Professional coffee knowledge exchange more coffee bean information please follow the coffee workshop (Wechat official account cafe_style)

Guide reading

Teacher Han Huaizong once said: "the oil and gelatin of coffee create a smooth taste in the mouth, while the polyphenols of coffee will produce a rough astringency, just like a devil's tail, running wild in the mouth, making it unpleasant. "

If in the wine point of view, astringency is very important, but in the coffee point of view, astringency is not pleasant. So where does the astringency of coffee come from? Why does coffee feel astringent?

What is astringency?

Astringency is the opposite of smoothness, which is the roughness felt at the entrance of coffee. This taste mainly comes from dicaffeoylquinic acid, which is degraded by chlorogenic acid in coffee during baking, which condenses with the protein of saliva and makes the oral epithelium feel astringent. The quality of raw coffee beans determines the amount of chlorogenic acid, and it is easy to cause the green taste of coffee beans if they are roasted too lightly. In addition, a small amount of grape acid in coffee is also a source of astringency.

What are the reasons for the astringency of coffee?

① raw bean varieties contain too much chlorogenic acid

The raw beans of ② coffee are too fresh, resulting in incomplete dehydration during baking

There are too many defective beans in ③ baking.

The parameters and techniques of ④ in brewing coffee

| | Raw bean varieties contain too much chlorogenic acid |

Chlorogenic acid is one of the "criminals" of coffee bitterness and astringency, accounting for 6% and 8% of raw coffee beans. Chlorogenic acid is degraded into quinic acid by baking. Quinic acid is a phenolic acid, which is non-volatile, so it can not be smelled through the sense of smell, but it tastes bitter and astringent.

Chlorogenic acid reflects whether coffee trees are planted properly. The good planting environment, high altitude and reasonably planted high-quality coffee beans will contain much less chlorogenic acid, which makes Robusta coffee beans taste worse than Arabica coffee beans because Robusta has higher chlorogenic acid content than Arabica coffee beans.

| | Coffee beans are too fresh, resulting in incomplete dehydration during baking |

The water content of fresh (new season) coffee beans is 13%, and the water content of raw coffee beans will affect the heat transfer during roasting. The fresher the coffee beans are, the higher the water content is, the more prone to dehydration incompleteness in the baking process.

Coffee beans with high water content are easy to be cooked when roasted, but the bean core is still raw. This situation of coffee beans in the cup test will drink some herbaceous flavor, and with a green, stinging feeling. Therefore, Qianjie will prolong the dehydration time when baking coffee beans in the new season so that the bean surface and core are heated evenly.

| there are too many defective beans during baking

If there are too many defective beans, the baking process can easily cause uneven development or uneven dehydration. Even some defective beans can directly affect a whole batch of coffee beans as long as they are present during baking. For example, immature coffee beans will have the taste of fried melon seeds when roasted, but also make the coffee salty and astringent; polluting fermented beans will produce sour taste; and moldy coffee beans will smell moldy during baking.

Qianjie coffee will select the raw beans before roasting to avoid the above situation, and after the roasting is finished, the coffee beans will be selected and packaged again.

| | parameters and techniques for brewing coffee |

If none of the above problems, then there are two main reasons for the astringency of coffee: insufficient extraction-excessive extraction.

The situation of insufficient extraction may be that the coffee beans are ground too coarse, which reduces the extraction time; the temperature of the brewing water is too low, and only the sour substances of the coffee are extracted; steaming and uneven water injection in the brewing process lead to some insufficient extraction and some over-extraction of coffee powder. The flavor of coffee with insufficient extraction is characterized by excessive sour taste and acerbity.

The situation of excessive extraction may be that the coffee beans are ground too fine, which increases the extraction time; when the water temperature is too high, the pleasant flavor substances in the coffee powder will be released completely, and the taste of wood fiber will be released; the method of water injection is too "rough". The excessive tumbling of the powder layer leads to over-extraction. The over-extracted coffee flavor is characterized by bitterness, bitterness and mixed taste at the end.

Is the tea in the coffee astringent?

Tea ≠ astringency! The sense of astringency is understood as the sense of tea because some friends think that it is normal for tea to be bitter. But in fact, the astringent taste of tea is due to the high water temperature or the wrong brewing method (of course, we do not rule out the bad tea varieties). Qianjie will feel the tea feeling of Tieguanyin when tasting the green rose summer coffee in the jadeite manor, because the Huigan of the green label rose summer rhyme is very similar to that of Tieguanyin, and the sweet feeling can stay in the mouth for a long time.

For more boutique coffee beans, please add private Qianjie coffee on Wechat. WeChat account: kaixinguoguo0925