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Most high-end grinders used for espresso powder are defined by grinding time, but the official standards of Specialty Coffee Association SCA are defined by weight. So what is the difference between the two? Why do people continue to use timing grinders? How can we ensure that the powder dosage from the grinder is correct?
To explore these issues, the author interviewed Lauro, the product manager of Simonelli Group coffee machines and grinders, who developed well-known brands such as Nuova Simonelli and Victoria Arduino.
The following are the author's findings.
What is the timing and constant weight grinder?
Let’s look at an example of an espresso recipe. The starting point of the recipe is usually the amount of coffee powder in the brewing handle and the end of the coffee liquid amount from the coffee machine.
But how do we define these quantities? Does it depend on weight, volume, or something?
Lauro said: "In SCA's coffee technology course, if you go to the barista intermediate or expert level course, weight is used as a measurement, including brewing ratio, formula, everything is calculated by weight, not by volume. "
However, there are timing and constant weight grinders on the market.
The timing grinder grinds coffee beans within a specific time, and the length of time is set by the barista. Take 18 grams of brewing recipe as an example. After testing, the barista found that it takes 5.8 to grind 18 grams of this coffee. Within seconds, the barista will set the grinder accordingly. In other words, the
fixed-weight grinder is measured by the weight of the powder falling into the brewing handle, and when it reaches the set weight, it will automatically stop grinding (this part is also set by the barista). How accurate is
timing grinder? The accuracy of
grinder is always different. Its reliability, grinding quality, and maintenance conditions will all affect the accuracy. (Lauro said that the Black Eagle fixed-weight grinder can be accurate to 1 gram, while the Mythos 2 grinder can grind the powder weight to 0.1 grams.)
However, if you look at the timing grinder, you must also consider the weight. Relationship with time.
Lauro said: "Every time you change a variable, the machine will automatically change another variable at the same time, so it will grind different weights of powder. For example, if you are adjusting the grinding degree, once you adjust the grinding degree to be coarser Or finer, it will cause a huge change in the amount of coffee powder per dose... If you change the type of coffee beans, you will again change the amount of coffee powder ground per dose.”
Different grinding settings require more or less time to Grind. Different coffees have different densities, which affect the volume and grinding time. The barista needs to recalculate the grinding time every time the coffee beans and recipe are changed.
However, this is not the only factor that affects the grinding speed. Lauro said, "If the bean hopper of the grinder is full or almost empty... depending on the amount of coffee you have in the bean hopper, different weights of coffee powder will be ground."
If the bean hopper is full , The weight of all the coffee will push the beans through the cutter head, which means more coffee is ground faster. As more coffee is ground and the bean container becomes empty, the pressure will gradually decrease. Using an almost empty bean trough, you can actually see the beans being forced through the cutter head, rebounding instead of being ground, and this is a situation caused by insufficient pressure.
Lauro said: "He has tested this. Grinding size, temperature, and all variables are fixed. We only use two bean chutes to test the same grinder. One of the bean chutes is filled with beans, The other bean trough is almost empty.” He said, “I see the difference in the amount of powder coming out of the grinder, and the difference in the amount of coffee per dose is as high as 1.5 grams. This example is tested with a Mythos 1 grinder, and it Under normal circumstances, the amount of grinding is accurate.”
can overcome many of the above-mentioned problems by using a fixed-weight grinder. As Lauro said, because the weight is measured directly, what you get is the coffee weight you want in the end.
But what if you can only use a timer grinder? How does
ensure the consistency of grinding?
If you want to maintain the consistency of brewing, you must ensure that you use the same amount of coffee every time.
Lauro said: "If you want an accurate dosage and there is no fixed weight grinder, you can only set the time to use the grinder, and then use the scale to weigh the amount of powder, check the amount of powder and increase or decrease manually. Of course, this way It takes time to do it.”
It is also important to calibrate the accuracy of the scale regularly, especially if you use more than one scale. In addition, if you use it in the store, you need to train the barista how to use this grinder efficiently and consistently.
Finally, pay attention to the agglomeration of coffee powder. Lauro said, "Coffee powder is difficult to measure, because coffee powder contains static electricity, so it will cause agglomeration. When you grind, the friction of the coffee beans on the cutter head will cause the static electricity of the coffee powder."
"And because of the coffee The powder is very small (micron), and it is more likely to cause agglomeration. Therefore, when the coffee powder leaves the grinder, there may be part of the residual powder in the grinder or sprayed away during grinding, resulting in a considerable amount of coffee powder The difference.”
Mythos 2 has a system to prevent agglomeration. If there is no such system to prevent it, even using a fixed-weight grinder may be slightly inaccurate due to agglomeration. Therefore, if your grinder does not have such a system to avoid agglomeration, please pay attention to this. If the coffee powder has a lot of lumps, please weigh it on the scale.
grinds a consistent and accurate espresso dosage, which is important to both the barista and the taster who carefully extract espresso. So, understand the equipment you use. Know whether your grinder is fixed or fixed weight. If necessary, use a scale to assist and make sure to calibrate the machine regularly.
, remember that even a difference of one gram will have a great impact on the feeling of the drinker.
Translated from Perfect Daily Grind
Translated by Chengzhen Coffee
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