The difference between hand-brewed Coffee and Cold extraction Coffee extraction principle of Cold extraction effect of Water temperature on Coffee extraction

Qianjie noticed that after buying a bag of coffee beans, many friends will make hand-made or cold-extracted coffee at home. These two are indeed the most convenient and quick ways of extraction, and the appliances that need to be equipped do not need to be too expensive.

A friend asked: why is the flavor of the same kind of coffee beans different from that of hand-brewed coffee?

-the difference between hand punching and cold extraction

First of all, the biggest difference between hand-brewed coffee and cold extraction is that hand-brewed coffee is extracted at high temperature, while cold-extracted coffee is extracted at low temperature.

Hand-brewed coffee, including hot hand brewing and ice hand brewing, uses hot water to come into contact with coffee powder at room temperature to extract soluble substances from the coffee. The extraction rate is fast at high temperature, and the flavor and taste change quickly, so it needs to be drunk as soon as possible.

Ice hands will reduce the proportion of powdered water on the basis of hot hands, flush out a cup of coffee with higher concentration with less hot water, and then cool down under the addition of ice to form a chilled taste.

Cold extracted coffee, also known as cold soaked coffee, coffee powder soaked in normal temperature water or ice water, placed in the refrigerator in a low temperature environment for 8-24 hours slow extraction, filter coffee grounds to get iced coffee. The cold-extracted coffee reacted at low temperature can be kept in the refrigerator for 3-5 days, and the flavor forms a fermented taste with the storage days.

-Coffee tastes different with different brewing methods

Qianjie chose a kind of shallow water to wash Yega Xuefei Ding coffee beans, and compared the flavor of three different cooking methods: hot hand flushing, cold extraction and ice hand flushing.

Hot hand Chong has a complete front, middle and back section, you can taste the sweetness of jasmine and honey, the bright acidity of lemon and citrus, and the lasting aroma of green tea in the mouth. With the decrease of temperature, you can feel the change of flavor and the layers are rich.

Cold extracted fruit Dingding Coffee, after being fermented in the refrigerator for one night, has a thin layer of oil on the surface, the aroma is weak, the entrance shows the sour aroma of berries and citrus, the taste is sweet and has the taste of iced fruit tea, but the flavor level is relatively general.

Ice hands, which are also ice drinks, grind more finely and extract higher concentrations of coffee liquid in hot water, so coffee dissolves more substances than cold extract. Although the flavor is not as plump and rich as the hot hand, the flavor tonality is not much worse, and the cooling of ice makes the coffee in the cup more sour and sweet and refreshing.

-flavor substances dissolve at different temperatures

Coffee contains quinic acid, amino acids, tannic acid, caffeine, oil and other substances. In the process of extraction, there will be a series of chemical reactions between water and coffee, and the water temperature directly affects the extraction rate of different components in coffee.

In the coffee brewing stage, the small molecules of fruit acid come out first, then the sweet molecules, and finally the bitter macromolecules. With the increase of temperature, the faster the speed of the extracted substance, a variety of factors may affect the taste of coffee, so it is necessary to carefully control the extraction rate when hand-flushing.

The bitter substances extracted at low temperature are much less than those extracted at high temperature. In order to improve the extraction rate, the contact time between coffee powder and water will be prolonged.

However, even if we improve the extraction rate of coffee, the rich flavor molecules brought by the movement of water molecules at high temperature can not be released at low temperature. The alcohol thickness and Body of a cup of coffee come largely from bitter substances, and the coffee without bitter substances is thin and not full enough.

Before launching a coffee bean, Qianjie will pass the cup test, excite various aroma substances in the coffee with 94 degrees hot water, and then describe the various flavors on the label. All flavor descriptions are based on high temperature extraction and only part of the flavor substances are extracted at low temperature, which is why the flavor of cold-extracted coffee is not as saturated as that of hand-brewed coffee.

-what coffee beans do you choose?

Qianjie has also mentioned in previous articles that light-roasted fruit-flavored coffee is more suitable for cold extraction than deep-roasted coffee. Because if the grinding degree of deep-roasted coffee is not adjusted properly, it is easy to have bitter taste under the action of ice.

If you want to store a bag of coffee beans at home and cook them by hand and cold extraction at the same time, while drinking more rich and varied tastes, Qianjie suggests that you can choose specially processed coffee beans with high flavor recognition. For example, Shirley in Honduras, Costa Rican musicians series, Colombian Flower Moon Night, Dorothy in Ethiopia …...

In this way, you can not only drink the rich aroma of hand-brewed coffee, but also taste the cold and mellow taste of iced coffee.

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