Espresso production skills | what is the effect of the temperature change of coffee powder on Italian concentrated extraction?

Professional coffee knowledge exchange more coffee bean information please follow the coffee workshop (Wechat official account cafe_style)

As a competent barista, have you ever worried that the water temperature of your espresso machine will be out of line? Well, I'm telling you, the temperature of the coffee powder you use may change more!

The relationship between the temperature change of coffee powder and the final extracted Italian concentrated quality is often ignored, but it does exist, and in recent years, the industry has begun to pay attention to this issue.

Does your bean grinder heat the coffee powder?

Now there are many different types of coffee grinders on the market for everyone to choose from. However, whether it is a flat knife or a cone knife, a ceramic cutter head or a metal cutter head, they all use a cutter head instead of a blade.

This means that in the bean grinder, there are two cutters, and the thickness of grinding depends on the size of the gap between the two cutters. When we grind coffee beans, at least one of the two cutters will rotate and then crush or cut to grind the coffee beans into fine particles.

However, friction is inevitably involved in this process, and everyone should know that friction generates heat. This heat is transmitted directly to other parts of the grinder, as well as to the coffee powder itself. Therefore, unless you use an extremely professional bean grinder, the immediate temperature of the mill will change with running time.

What is the extremely professional bean grinder like? They will have a cooling system. Including fans, heat exchangers and radiators, etc., used to dredge the heat generated in the grinding process. However, even these bean grinders with a cooling system can not completely avoid the heat of the knife head, nor can the barista monitor the temperature of the coffee powder.

Depending on your grinding speed and grinding time, the grinding temperature of coffee powder can range from 20 ℃ to 80 ℃, with a temperature difference of up to 60 ℃. Such a large temperature difference is sufficient to have a significant impact on your Espresso extraction, resulting in fluctuations in quality and stability.

What is the effect of the temperature change of coffee powder?

When the temperature in the bean grinder rises, you will find that the extraction time of Italian concentration will be shorter and the flow rate will be faster. I believe that people who have worked in large coffee shops should have the experience that after continuous grinding and extraction of many cups of Italian concentration, your concentration flow rate will change, so if you do not want the product to get worse, you have to fine-tune the grinding degree slightly to make up for this effect.

Then, when the peak production period is over and the frequency of the bean grinder becomes lower, the temperature will drop slowly, and it is time to readjust the grinding degree. Maybe it doesn't sound like a problem, ah, professional baristas know how to adjust the parameters according to the extraction situation at any time, which is good. However, the more the barista adjusts the parameters, the greater the risk of extraction errors, product instability and improper extraction.

More importantly, as the temperature of the bean grinder rises, so does the grinding time of coffee powder. This will cause a chain reaction. The temperature of the bean grinder may even affect the ratio of powder to water. Because most of the quantitative bean grinders on the market actually fix the amount of grinding powder by timing. You can judge your concentrated extraction by timing and observing the extraction, but you can't observe the performance of the bean grinder with temperature.

Why does the temperature of the bean grinder affect the extraction and grinding time of coffee powder? I'm sorry, but most of the current studies still don't have a perfect explanation. Because the microscopic process of grinding coffee powder is so complex, we can't even make sure that the analysis is correct.

However, whatever the reason, one thing is certain: changes in temperature will have an impact on the extraction of coffee.

Keep the bean grinder calm.

It is impractical to keep the bean grinder cool, although it is much easier to speed up the cooling of the bean grinder to prevent the knife head from heating up too quickly. For example, a bean grinder uses aluminum to make a shell to speed up heat dissipation and keep the cutter head cool. However, it is far more expensive to cool something down than to heat it up, because cooling requires more energy.

In other words, as a tuhao coffee lover, you can do everything you can to cool the bean grinder at a huge price, but it is impossible for a coffee shop owner to pursue efficiency and commercialization, which is not realistic.

In fact, do we really need to spend a lot of money to cool the bean grinder? Ten years ago, it was generally believed that coffee should taste good while it was hot, but now it is clear that this view has been questioned. With the development of the times, the innovation of science and technology will eventually refresh people's understanding.

The temperature stability of grinding is more important than that of grinding.

Perhaps the crux of the problem is not whether the temperature of the cutter head or coffee powder is high or low, but the temperature change itself.

Irish barista champion Colin Harmon and his team have done experiments: they grind several different coffee beans at different temperatures and compare and analyze the extracted coffee. It was found that there was no significant difference in the flavor quality of these different coffee beans in this experiment.

No matter what the temperature of the cutter head of the bean grinder is, how fast the speed of grinding is. As long as the temperature is stable, each kind of coffee bean can extract Italian concentration with the same parameters and flavor performance. This study shows that the biggest problem with the temperature of the bean grinder is not the temperature, but the temperature instability.

Last

The extraction temperature of coffee powder is not one of the variables we discuss on a daily basis, but it does affect quality and stability. For busy coffee shops, the heating up of coffee powder caused by the continuous operation of bean grinders does cause a series of problems.

But like other parameters in coffee brewing, stability and consistency are often the key. The temperature at which the coffee powder is ground is not important, what is important is how to keep the temperature stable.

Article translated from: www.perfectdailygrind.com

END