Does it taste better to make cold extract coffee with room temperature water or warm water? Why is cold extract coffee low in acidity?

As one of the representatives of iced coffee, cold extraction is usually made with room temperature water (about 20 - 30℃). However, due to low extraction efficiency, it is necessary to soak for a long time to obtain more flavor substances to highlight the sweetness and richness of the coffee.

Experienced friends know that making a pot (cup) of cold extract can take 5 to 6 hours as quickly as possible, and nearly a whole day as slowly as possible. Compared with other coffee practices, cold extract is obviously a type of "slow work produces fine work." Based on this, some people have proposed using warm water to soak coffee powder to shorten the production time of cold extraction.

With a skeptical attitude, Qianjie searched some articles and found that using warm water to brew cold extract coffee is nothing new. Many people have also done related experiments, saying that the coffee will taste better. So, today we will also discuss this method of play.

The difference between making coffee in cold water and making coffee in warm water

In essence, compared with most high-temperature extraction methods, long-term cold soaking can more fully release the small molecules of sweet and sour substances in the coffee particles. At the same time, with the blessing of the refrigerator, it will further suppress the appearance of bitter substances, thereby giving the coffee a better taste.

The Coffee Science Foundation and the Fine Coffee Association have jointly published a research report on cold-extracted coffee, analyzing that coffee soaked and extracted at low temperatures will have more fruit and fruit aroma than high-temperature extraction, and at the same time, bitterness, sourness and blemish taste will also be less.

For the same coffee bean, when extracted with the same gram weight, proportion, and degree of grinding, the rates at which various chemicals in coffee dissolve in hot water and cold water are different. According to research statistics, different sensory attributes and extraction temperatures have significant changes. Among these four attributes, bitterness, sourness and rubberiness were significantly higher in high-temperature extracted coffee than at low-temperature extraction, while floral fragrance was higher in low-temperature extraction.

During the high-temperature extraction process, the tannic acid in coffee will be preferentially decomposed into pyrotechnic acid, and various fatty acids will also dissolve more and faster in hot water, making it easier to be accompanied by bitterness and sourness. Under low-temperature extraction conditions, the types of sour compounds will gradually decrease as time goes on, so the sour taste of cold-extracted coffee will be greatly reduced. At the same time, the refrigerated environment also weakens the volatilization of coffee aroma, allowing more aroma "Locked" in the coffee.

When we use lukewarm water to extract coffee, it can not only drive some substances to undergo thermal movement, allowing small molecule particles to gradually be released in a short period of time, but as the added water slowly warms and cools, the molecules The thermal movement will prevent the coffee particles from gathering together, making subsequent coffee extraction more uniform, and also inhibiting the precipitation of bitter substances.

Operation of soaking in warm water and cold extraction

In this test, cold extraction coffee was brewed in warm water, using Qianjie Arida Kaduai, a Panamanian coffee bean with anaerobic sun exposure. It has soft floral flavors, sweet orange and plum sauce flavors, and has a sweet and sour taste. Light, more suitable for hand-brewed and cold extraction. In addition, considering that the increase in temperature may easily cause the very fine powder to be over-extracted, Qianjie will slightly roughen the grinding to achieve balance.

Specific extraction parameters are as follows:

Coffee powder: 30g

Abrasion degree: EK 43s-10 grids (sieve rate of No. 20 sieve is 75%, C40-26 grids)

Powder to water ratio: 1:11

Water temperature: 45℃

Prepare a clean container, pour in the ground Alida coffee powder, then add 330ml of warm water at 45 ° C, and stir well. After the coffee liquor returns to 35 - 40℃, seal it and place it in the refrigerator for refrigeration. After about 3 hours, remove it and stir again, then filter the coffee grounds clean.

For comparison, Qianjie made another pot of normal-temperature water version of cold extraction. The parameters were: 30g coffee powder, grinding degree EK43 s-10 grids, powder-to-water ratio 1:11, and soaking time 7 hours.

Under the same parameters, using normal-temperature water + long-term low-temperature extraction of Alida cold extract, the taste will have light floral flavor, pineapple, orange flavor, and the lightness and sweetness of black tea, accompanied by a slight fermentation feeling and balance. Just right;

The extraction with warm water at 40 ° C + low temperature for 3 hours presents an elegant aroma of bergamot and jam. The taste is like the sweetness of yellow sugar and peach. Unfortunately, the flavor is weak and the aftertaste is short. It is speculated on the front street that the soluble substances have not been cooked in place. So, Qianjie sealed the coffee and sent it to the refrigerator. It was refrigerated for 3 hours and tasted again. Sure enough, all charms were expressed more fully.

Some operating experiences 1. During this exploration, Qianjie also used several different styles of coffee beans for practical operation. It was found that the use of medium-light baked beans with the flavor of sweet fruits is more suitable for cold extraction with warm water, such as sun-cured Alo, honey-treated strawberry candy;

2. For friends who don't have a thermometer at home, Qian Jie thinks that it doesn't matter. The so-called warm water is actually a state close to the human body's temperature. When we touch it, we can just warm our hands.

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