What is the principle of hand-brewed coffee? how to choose coffee beans?

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The advantage of hand-brewed coffee is that it does not pick coffee beans at all, and unlike the mocha pot, it takes a short time to extract, and it is not easy to drink layers of taste if the taste buds are dull. If you make it by hand, no matter what kind of coffee beans from any country, you can drink the pure taste, aroma and level of this kind of coffee. But there is a premise to pay attention to, because the coffee has a taste period, and once the coffee is ground into particles or powder, the surface area of contact with the air increases, which will accelerate the oxidation rate and lose the aromatic substances, unless it is impossible to bring hand-made equipment away from home, otherwise, it is recommended that you must freshly grind, drink and grind, so that you can drink the delicious coffee.

The principle of making coffee by hand

The so-called brewing coffee is actually the process of extracting the molecules from the coffee cells, and this process includes the following three steps: wetting, dissolution, and release, which occur one after another and interact with each other, and finally produce the special flavor of coffee. We will explain the following one by one:

Step 1: get wet

Literally, coffee powder gets wet when it touches water, which is the starting point when coffee cells begin to release molecules.

It should be noted that roasted coffee beans are filled with carbon dioxide, and the fresher the beans, the more carbon dioxide they contain. When the hot water touches the coffee powder, the carbon dioxide will run out first, forming a layer of air bubbles on the surface, and you will see the coffee powder in the filter cup begin to expand (pictured below). At this time, the coffee cell is like a supermarket that a lot of people have to squeeze out of the inside, and people outside can't get in at all-in the same way, hot water outside the cell can't get into the cell. Therefore, after wetting the coffee powder, we will stop injecting water and wait for the complete release of carbon dioxide and the coffee powder to stop expanding and then continue to heat the water in order to achieve a better extraction effect.

Step 2: dissolve

Refers to the process of dissolving soluble molecules in coffee cells in hot water, which is the most important step in deciding to extract the flavor of coffee.

Coffee beans 2/3 are made up of insoluble cellulose and 1/3 are soluble odor molecules that are dissolved in order according to the size of the molecules when they come into contact with water. The first small molecules dissolved include acidity and aroma, then the sweetness of middle molecules, and finally the bitter taste of macromolecules, which is where the different levels of coffee taste come from. Therefore, if you like the sweeter taste, the extraction time should be shorter, because the longer the hot water stays on the coffee powder, the more bitter molecules will be dissolved.

Step 3: diffusion

After the odor molecules dissolve, they leave the coffee cells by osmosis, a process called diffusion. After the odor molecules are diffused into hot water, the final coffee extract is formed.

Do you smell like flowers or mellow?

But then again, how do you choose beans for hand-brewed coffee? Are there any principles for choosing coffee beans? In the face of a wide variety of coffee from all over the world, few people are not lost in the coffee market. Ding Xiaoyu, manager of Dunnan Banner of European Coffee Farm, suggested that you can choose according to your personal taste and preference. If you like the fragrance of flowers, you can choose Ethiopian, Guatemalan or Colombian coffee. Among them, the jadeite manor geisha coffee beans originated from the geisha mountains in southwestern Ethiopia, with the aroma of jasmine, rose and bergamot, cold drink can feel the sour level more. It also has a different flavor.

If you like the mellow taste, coffee beans from island-type countries are the most suitable. Because the climate is prone to haze, it is easy to cultivate the layers and aromas of coffee beans, such as Hawaii Kona, where moderate acidity mixes light wine aromas and nutty aromas. but one of the favorites of coffee glutton. The sea turtle coffee located in the Galapagos Islands off the coast of Ecuador in South America is known as a rare pearl in boutique coffee. As for coffee that likes heavy feeling, Ding Xiaoyu said that you can try Kenyan or Peruvian coffee. Kenya is still using the ancient sun method to make coffee. Kenyan Kajia AATOP coffee has a strong pulp aroma, and then slightly sour, which also wins the hearts of glutton.