Introduction
Every day before the coffee shop opens, they are busy with preparations. One of the most important things is to adjust the espresso. Some friends also asked before how fine the coffee powder used in an espresso machine should be?
Espresso grinding issues
Drip filter coffee, such as hand-brewed and ice-drip coffee, has coarser ground particles, and we can also use a sieve to identify them. However, the grinding required by the espresso machine is as fine as possible, which looks like dust to the naked eye.
There are also two problems with the grinding degree of espresso coffee. One is that different espresso machines have slightly different requirements for grinding degree. The other is that when the grinder grinds the beans into such a fine powder, the cutterhead is prone to wear. Obvious wear and tear will affect the fineness of the grinder.
Especially for the first reason, when some customers have espresso coffee machines but do not have grinders, Qianjie can only grind them according to the grinding scale used by their own products when pre-grinding them. There will be differences in the specifications of the coffee machines. Resulting in a grinding degree that cannot be 100% accurately matched. (The relationship between grinding degree and machine will be discussed below)
Why do I need to adjust it frequently?
The "frequent" here is compared with hand brewing. In hand brewing, the grinding scale of each coffee bean is basically fixed, while the grinding scale of espresso coffee is adjusted at least 1-2 times a day.
The reason is that due to the influence of the air pressure and humidity of the day, as well as the fineness of the grinder, the ground coffee powder does not appear to have any change to the naked eye, but when you put it on the coffee machine and press the extraction button, you can see whether it is coarse or fine. It showed. So we have to adjust the Italian grinder every day to match the "pretentious" coffee machine (after all, it has half the say in whether the espresso tastes good or not).
So how to adjust the grinding size suitable for Italian coffee?
Most of the parameters that are changed when debugging espresso in daily life are only the grinding degree, and the grinding adjustment is often only an inconspicuous 0.1 grid.
Before grinding, we need to clarify a few goals. First, why we need to grind, because the extracted espresso does not meet our preset requirements, including extraction parameter requirements and flavor. Second, when adjusting the grinding, you should keep other parameters as unchanged as possible, such as the skillful powder pressing technique and the consistent amount of powder and liquid. Otherwise, your grinding will be full of uncertainties.
The structure of the Italian coffee grinder is generally a horizontal flat knife. There will be a scale adjustment disk on the outside with a scale engraved on it. The larger the value, the coarser the grinding. Taking the Pegasus grinder used in the past as an example, the Italian grinding degree hovers between 1.5-2.5.
In daily debugging, we will abide by the principle of an extraction formula, that is, the amount of powder, extraction coffee liquid and extraction time. The amount of powder and coffee liquid form a powder-liquid ratio relationship, which is generally 1:2, and the extraction time is between 20-30 seconds.
For example, Qianjie used 20 grams of powder to extract 40 grams of coffee liquid in one extraction. The time used was 18 seconds, which is obviously fast, that is, the coffee powder is thick, so it needs to be fined, and because 18 seconds and 20- The difference between 30 seconds is not very big, so you can adjust it by 0.1-0.2 steps when adjusting. After Qianjie fined it by 0.2 steps, the extraction time was 23 seconds, which is in line with the extraction formula, but it does not necessarily mean it tastes good, so you still have to taste it to find out the shortcomings and then make fine adjustments.
For another example, Qianjie used 20 grams of powder to extract 40 grams of coffee liquid in one extraction. The time used was 48 seconds, and the first drop of coffee liquid did not appear until 15 seconds later. There was no need to determine the amount of powder and press the powder. In the case of the problem, it is determined that the coffee powder is too fine, and the resistance of the coffee powder is too great, causing water to be unable to penetrate the powder layer. Therefore, it needs to be coarsened, and because the range of 20-30 seconds is too far away, you can first coarsen it by 0.5 steps and observe the extraction time, and then slowly adjust it. It usually takes 2-3 extractions to determine.
Extraction suggestions for home espresso machines
Many players are equipped with espresso machines and grinders at home, but the output is relatively small, only about 1-2 cups a day. So if you have to adjust 2-3 times of espresso for 1-2 cups a day, it is obviously not enough. It's a bit wasteful of people and money. Here are some suggestions for this street.
1. The powder loading capacity is the maximum recommended powder capacity of the powder bowl. For example, the reasonable capacity of the powder bowl used in Qianjie is 18-20g. Choosing a powder loading capacity of 20g will be more stable.
2. Since the production volume is usually small, the impact on the grinding loss problem will not be too great. Just adjust the grinding degree and record it when using it for the first time. If you usually extract one cup or two cups, just follow the grinding scale, the powder-to-liquid ratio is 1:2, and the time should be controlled at 20-30 seconds, and you’ll be fine.
Some people may also ask, there is a 10 second difference between 20 and 30 seconds. If one cup is extracted for 20 seconds and the other cup is extracted for 30 seconds, is there a big difference? First of all, there is a difference, but they are basically within the extraction range of qualified espresso. If you do not drink espresso alone, but need to add milk to make a latte, or add water to make an Americano, then there is a difference. It will be greatly reduced. If it is not for academic research, there will basically not be much negative feelings in the flavor tasting.
Reference: kafeigongfang, makecoffee.cn