How to make cold coffee cold coffee is difficult to make cold coffee

The happiness of summer is probably to be able to drink a cup of cold coffee that can relieve summer heat without leaving the house. Because of the simple production method, even those who do not know how to make coffee can easily make a mellow and smooth taste, rich and full flavor, as a whole clean and refreshing, suitable for summer taste of iced coffee.

Different from the common iced hand brewed coffee and iced American coffee, cold extracted coffee is extracted at low temperature in the whole process. On the other hand, both hand-brewed coffee and American coffee are extracted at high temperature and then cooled and diluted with ice.

In a coffee bean, the coffee flavor accounts for only 30% of the total, and the remaining 70% is wood fiber structure. And 30% of the flavor is not fully extracted, because more than 10% of it belongs to bitter substances. Proper extraction of bitter substances can bring appropriate alcohol thickness to the coffee and increase the body of the coffee itself. Coffee lacking bitter substances tastes thin, while coffee with too many bitter substances will dry up and become astringent. We only need to extract 18% of the coffee's 22% flavor.

The advantage of high temperature extraction is that the heat in water can promote the movement of water molecules and extract the flavor molecules from coffee particles in a short time, but the disadvantage is that if the water temperature and the grinding degree of coffee particles are not properly controlled during brewing, it is easy to excessively extract the bitter molecules, resulting in different degrees of bitter taste of coffee.

On the other hand, low temperature extraction will promote the movement of water molecules because there is no heat, and low temperature can effectively inhibit the release of bitter molecules. However, due to the low temperature, the flavor extraction time of coffee will be relatively prolonged, and it usually takes 6-12 hours to extract the sweet and sour substances more completely. Therefore, the coffee extracted at low temperature usually has a full sweet and sour feeling, but if the soaking time exceeds 12 hours, the wood fiber will also release the flavor of the roots because of soaking for a long time, although these tastes are not bitter, but it will affect the overall aroma performance.

For the flavor of cold-extracted coffee to be more complete, the coffee particles used should be a little thicker than the hand grinding of coffee beans. For example, Qianjie coffee Ethiopia Huakui coffee beans used for hand-brewing is 80% overscreening rate of China's 20 standard screen, then the thickness used for cold-extracted coffee production requires 75% overscreening rate.

Why do you want to increase the extraction concentration of cold-extracted coffee instead of thickening the grinding degree? In the cold extraction production of Qianjie coffee in the past, it is found that the coffee powder which is calibrated by hand will agglomerate (clump) in the soaking process. So using the same coffee bean, the same soaking time, the same environment static extraction, using different scales for extraction, through the experiment to compare the concentration difference between the two ~ the experimental results show that the rough grind coffee powder in the delicate and low temperature environment, the extracted concentration will be high.

This is because when the temperature of water is close to room temperature / zero, the molecular motion will also be reduced / zero. Without the counterbalance of molecular thermal motion and the attraction between solid molecules, coffee particles will "clump", that is, caking. So when the coffee is ground finely, the hugging situation will be so large that the coffee powder in the middle of the ball can not be fully extracted.

For the production of cold-extracted coffee, it is usually only necessary to prepare a clean, oil-free sealed container and the materials used to filter the coffee (coffee filter paper / tea bag / high-density filter / cloth bag, etc.). Then mix the coffee powder with ice water and put it in the refrigerator for 8-12 hours. Qianjie coffee is recommended to use 30g coffee powder, extracted in the ratio of 1:13 (that is, 30g coffee powder is soaked in about 400g water), after the extraction is finished, filter out the coffee grounds and taste.

Used for cold coffee beans, Qianjie coffee uses sweet and sour coffee beans with strong flavor.

For example, light roasted coffee beans in Africa and Central and South America: Ethiopian Huakui coffee beans sold in Qianjie Coffee (berry juice conditioned), Panamanian butterfly rose summer naturally mixed coffee beans (scented tea tempered), Costa Rican Mozart coffee beans (preserved fruit conditioned) are very suitable for the production of cold-extracted coffee.

Or specially treated coffee beans, such as Ethiopian Dorothy coffee beans sold in Qianjie Coffee (white peach oolong), Colombian Rose Valley coffee beans (fruit wine chocolate flavor), Honduran sherry coffee beans (alcoholic vanilla cream flavor) and so on.

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