What degree of grind should I use to make coffee by hand? How fine should the coffee powder be ground with cold ice drops? What is the No. 20 screen? How fine are the grains of fine sugar? What is the appropriate grind for the espresso?

No matter what method we use to make coffee, whether it is hand-brewed, cold extracted, or Italian, we need to grind the coffee beans into powder before starting making it. The purpose of this is to increase the water-contacting surface area of coffee, speed up the dissolution of flavor substances, and give the washed coffee a fuller taste.

But as we all know, not all soluble substances in coffee beans are high-quality delicious, but there are also some unsavory and unlikable substances. If we want to make a delicious cup of coffee, we need to dissolve a large amount of delicious substances in the coffee beans while avoiding the precipitation of those bad substances. To do this, we need to use appropriate extraction parameters to control the flavor substances dissolved in the coffee. The grinding degree of coffee powder is one of the most important parameters. Many times, the reason why we can't make a cup of coffee well is that we haven't found the right degree of grinding. The same is true no matter what kind of coffee.

Since there are many friends who have asked about the degree of grinding recently, there are various extraction methods such as cold extraction, hand-flushing, and mocha pot. So today, Qianjie came to share what kind of grinding degree should be used in various extraction methods!

First, what we need to know is... Because the grinding degree of coffee powder does not have an intuitive value like water temperature and water volume, many times when we communicate the grinding degree of coffee powder, we always use analogy to describe the thickness of coffee powder. For example, items such as "fine sugar" and "flour" are used to describe the particle size of coffee powder. But this method obviously has a very big drawback, because the naked eye cannot accurately determine the size of the coffee powder particles, it is just a rough idea. Therefore, this easily leads to the fact that everyone's "fine granulated sugar" particles are of completely different sizes. Even if other parameters are the same, the taste of the brewed coffee will be very different.

Then everyone uses a different bean grinder, so we can't share the grinding degree of coffee powder through the scale of the bean grinder. At times like this, Qianjie would recommend using the screen pass rate for communication, and this is also the method Qianjie would use when sharing the degree of grinding in this article. The so-called sieve refers to the No. 20 China standard sieve with a pore diameter of 0.85mm. This is a tool that can grade and detect the particle size of material particles. It can also be used to calibrate coffee grindiness.

The method is very simple! We only need to pour the ground coffee powder into the sieve and shake it until no particles fall from the sieve, and then weigh the sifted particles to calculate the pass rate to get a rough grinding thickness. Take an example here on Qianjie. Suppose we grind 10g of coffee powder and then pass through the sieve is 7.1 g of coffee powder, then the pass rate of this grinding degree is 71% of that of the sieve No. 20. The higher the pass rate, the finer the ground of the coffee, and vice versa.

After everyone understands the calculation method and meaning of the pass rate, you can intuitively know how thick and fine the abrasive degree shared by Qianjie is.

1. The grinding degree of hand-brewed coffee The first thing to share is the grinding degree of hand-brewed coffee! Hand-brewed coffee is a trickle-filter extraction that quickly makes a cup of full-flavored coffee by manually injecting water. Since the overall extraction time is relatively short (brewing a pot of 15g coffee powder takes about 1 minute and 30 seconds to 2 minutes and 30 seconds), the grinding degree of the coffee powder will be relatively fine, so that the coffee can be quickly dissolved. Flavor substances.

Due to the density, different coffee beans will be ground with different degrees. Generally, Qianjie divides them into two categories: medium and light roasting and medium and deep roasting. The grinding degree of medium and light roasted coffee beans will be finer. The grinding scale used in Qianjie is the 10 scale of Ek43, and the pass rate of No. 20 sieve is 75%~80%. Then mix it with a water temperature of 90~93°C, a 2-minute brewing time (15g powder), and a powder to water ratio of 1:15.

When grinding medium and deep baked beans, the grinding scale will be thicker. For example, the grinding scale used in Qianjie is the 11 scale of EK43 and the screening rate of No. 20 sieve is 70% to 75%. Then mix it with a water temperature of 86 - 89°C, a 2-minute brewing time (15g of powder), and a ratio of powder to water of 1:15.

The above grinding and parameters are all hot rinsing parameters. If we want to brew ice by hand, the grinding needs to be finer than the original one, and then the ratio of powder to water is changed from 1:15 to "powder to water ice ratio"1:10:5~6, and the water temperature and brewing time remain unchanged.

2. The grinding degree of cold extracted coffee (ice drops/cold bubbles) is the grinding degree of cold extracted coffee! There are two main types of cold extracted coffee, cold bubble and ice drop. Both are extracted using cold water. The difference is that the former is a soak extraction, while the latter is a drip filter. Due to the poor penetration of cold water and the very low extraction efficiency, it is best to use a finer grind than hand-brewed coffee to grind the coffee beans. Generally, the grinding used in Qianjie is 80%~85% of the sieving rate of No. 20 sieve, and then matched with a powder-to-water ratio of 1:10 (ice drops are the powder-to-liquid ratio), and a soaking time of 8~12 hours (ice drops are 7 drops in 10 seconds).

It should be noted that, as Qianjie has always shared, the grinding of cold extract coffee is not as fine as possible. Because some coffee powder will accumulate at the bottom after being ground due to its high density or excessive fine powder, the extraction rate will be reduced. If you find that the taste of coffee is not full enough after using the above-mentioned parameters in Qianjie and taste widower and light, you may wish to roughen it, grind it or use tea bags to sub-pack coffee powder and soak it, so that you can effectively improve the coffee. The extraction rate makes the taste more full.

3. The grinding degree of the French press pot/smart cup is then the grinding degree of some soaked coffee. The soaked extraction has a higher fault tolerance rate than the drip extraction such as hand-brewed coffee, because the coffee powder is soaked for a long time. During extraction in water, there will not be too much disturbance to accelerate the dissolution of flavor substances. Coupled with the concentration ladder, the "bitterness" can be stopped in time. Therefore, long-term soaking extraction methods such as French press pot, smart cup, and cup testing can use a relatively rough grind and then soak for a relatively long time. Take Qianjie as an example. The degree of grinding used by Qianjie when making coffee with a press pot is 70% of the sieve rate of No. 20. Then mix it with hot water at 94°C and soak it for 8 to 9 minutes at a ratio of 1:16.

Of course, if you want to shorten the soaking time, you can also choose to fine the grinding degree of the coffee powder or add stirring. For example, use the same grinding degree as hand-brewed like a cup test, then soak for 4 minutes, and finally remove the foam/filter out the coffee grounds to enjoy delicious coffee ~

4. The grinding degree of a mocha pot/espresso is finally the grinding degree of pressurized extractions such as a mocha pot and espresso machine! As mentioned at the beginning of Front Street, since this kind of extraction method allows coffee to be extracted in a short time, we need to use very fine grinding. However, because this type of grinding is very fine, we have no way to use a sieve to measure their particle value, so we can only judge whether the grinding is used correctly through the actual extraction and the taste of the coffee.

Take Qianjie as an example. When extracting espresso, Qianjie will use the formula of "20g of powder extracts 40ml of coffee liquor in 28 to 35 seconds." First, the extraction plan is fixed, then the degree of grinding is adjusted to allow the extraction time to reach the target range in the plan. Finally, the tasting range is used to determine whether the parameters need to be adjusted. Since this is a long story and Qianjie has shared a lot of related tweets in the past, I won't go into it too much here. Interested friends can search for it yourself. The thickness of coffee powder used in the mocha pot is the same as that of espresso, except that the requirements are not so extreme and are similar to the size of flour texture ~

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