How to choose the time quantitative type and the fixed weight grinding machine? is the accuracy of the quantitative grinding machine high?

What is the time quantitative and fixed weight bean grinder?

First of all, let's start with Espresso's cooking formula. Usually when we talk about brewing the formula, we refer to the amount of coffee powder in the filter cup, in proportion to the amount of liquid actually extracted into the coffee cup. (amount of coffee powder / coffee liquid in the cup)

But how do we define this "quantity"? In terms of weight, volume, or is there another way?

Lauro told me that in SCA's CSP coffee skills course, if you take a mid-or high-level Barista course, all calculations are based on "weight". Cooking ratio, formula, etc., are based on weight, not volume.

However, in the market, we find that there are both options for quantitative time or bean grinders with fixed weight technology.

The bean grinder with a fixed amount of time will be ground according to the number of seconds set by the barista. For example, we want to grind 18 grams of coffee powder, after several repeated attempts, baristas will find that 18 grams of powder takes about 5.8 seconds to grind, so they will set the grinding time on the machine to 5.8 seconds.

In the bean grinder with fixed weight technology, when the coffee powder falls into the filter cup, it will directly detect its gram weight, and when it reaches the preset number of grinding grams, the cutter head motor will stop automatically.

Is the accuracy of time quantitative bean grinder high?

The accuracy (accuracy) of the bean grinder is always changing. Stability, grinding quality, maintenance, and precision (precision) all affect the accuracy of the bean mill (accuracy). (as Lauro said, the accuracy of the Black Eagle Black Hawk coffee machine is 1g, while the accuracy of Mythos 2 is 0.1g. )

Editor's note: for the difference between accuracy (accuracy) and precision (precision), please refer to Wikipedia

However, for the time quantitative bean grinder, we also need to consider another variable factor: the number of powders actually ground per second.

Lauro says that every time you change a parameter, even if you set the same number of seconds, the actual number of grams will be different. For example, after you adjust the grinding scale, whether it becomes thicker or finer, the amount of powder will change significantly under the same number of grinding seconds. If you change a coffee bean, similarly, you will find that although the number of seconds is the same, but the actual amount of powder is not the same.

Different thickness requires different grinding time. Different coffee beans also have different densities, thus affecting the volume and grinding time of the powder. Each time you adjust the parameters or change the coffee beans, the barista needs to recalculate the number of grinding seconds.

However, the thickness is not the only factor that affects the grinding speed. Lauro told me, "the amount of coffee beans in the trough will also affect the grinding speed." Depending on the amount of coffee beans in the trough, you will find that even if the number of seconds is set, the actual amount of powder will change. "

When the bean trough is full, the weight of the coffee beans will squeeze the bottom coffee beans into the knife plate, so the grinding speed will naturally be faster. When the coffee beans in the trough gradually decrease, the pressure on the coffee beans below will gradually decrease. When the bean trough is empty, you will find that some coffee beans will pop up from the knife head, which is the situation caused by the lack of upper pressure.

Lauro told me that he once did an experiment. We fixed the grinding thickness, temperature, and all other variables, and we only tested the difference in the amount of powder produced by the same mill when the bean trough was full and almost empty. We found that it could be as bad as 1.5 grams at most. But for example, like Mythos One, it doesn't have this problem, because it's more accurate, Lauro laughs.

But all these problems will be solved if we use the system of fixed weight technology. Because we actually weigh the powder directly.

But what if you use a time quantitative bean grinder?

How do you improve consistency?

In the end, if you want to have a stable and consistent cup quality, you must make sure that the amount of coffee powder used in each brewing is the same.

If you want to be very accurate but don't have a fixed-weight technology bean grinder, use a time ration grinder, match it with an electronic scale, check the number of grams in each handful, and adjust it manually, Lauro says. But of course, it will take some time. "

Occasionally the scale needs to be corrected, especially if you have more than one scale in your store. In addition, you also need to educate your employees so that they can use the scale effectively and continuously.

Finally, pay attention to the problem of caking. "Coffee powder with lumps is not easy to weigh," Lauro said. It is mainly because the charge is transferred to the coffee powder after rapid friction between the coffee powder and the knife head, and the coffee powder particles are very small, usually micron level, so caking is more likely to occur. "

When caking occurs, the caking may stay in the pulverizing channel of the bean grinder, or it may fall into the filter cup, which has a great influence on the number of grams of the ground powder.

The Mythos 2 bean mill is designed with "anti-caking blade" at the powder outlet. Without this design, even the bean grinder with a fixed weight system will not be very accurate because of caking. So, if your device doesn't have this design, please pay special attention to this.

Stable and accurate powder dropping and filling has a key impact on extracting a cup of high-quality espresso and maintaining the reflux of old customers. So take a closer look at your equipment and find out whether your bean grinder is a fixed amount of time or a fixed weight technology. If necessary, use electronic scales and remember to correct them regularly.

Please keep in mind that only one gram of powder may have a great impact on customers' flavor experience.