How to choose the grinding degree of coffee beans? What are the principles of coffee bean grinding?

Grinding coffee beans is the first step in brewing coffee, but it is also a step that many people fail easily. They either grind too finely or too coarsely, which indirectly affects the taste of the coffee. If you want to accurately control the coarseness of the coffee powder, it is recommended to use an electric grinder with adjustable scale to accurately control the grinding degree.

Generally speaking, a good grinding method should include the following 4 basic principles:

1. Choose the grinding size that suits your brewing method

2. The temperature generated during grinding should be low

3. The powder particles after grinding should be uniform

4. Grind just before brewing.

The best time to grind coffee is right before you cook it. Because ground coffee easily oxidizes and loses its aroma, especially if it is not properly stored, the coffee powder is easy to change its taste, and naturally it is impossible to brew a mellow coffee. Some people are afraid of trouble or don't want to buy a grinder, so they usually buy ready-ground coffee powder when they drink coffee at home. At this time, you should pay special attention to the storage problem. After opening the coffee powder, it is best not to leave it at room temperature at will. The more appropriate way is to put it in a sealed jar and refrigerate it, and don't store it with garlic, fish, shrimp and other strong-smelling foods.

Because coffee powder easily absorbs odors, it can easily become a strange-smelling coffee, and even the best quality coffee will be wasted. So some people put brewed coffee grounds in the refrigerator as a deodorant, which is a good way to make the best use of it.

No matter what kind of grinder you use, friction will generate heat during operation. As we have repeatedly emphasized before, most high-quality substances are highly volatile, and the heat from grinding will increase the rate of volatilization, causing the aroma to be lost to the air first.

Taking the Fuji coffee grinder as an example, the best coarseness of hand-brewed coffee powder is between 3 and 4 scales, and fine sugar can be used as a reference:

The coarseness of coffee powder is related to the amount and speed of the coffee components released when brewing coffee. Generally speaking, the coarseness of coffee powder can be divided into five levels: coarse powder, medium powder, medium-fine powder, fine powder, and extra-fine powder.

(1) Extra fine powder: suitable for Italian coffee

This is the easiest to understand, and the usage is relatively absolute. It is only used when making espresso. Because the extraction method is different from the principle of brewing at home, it requires pressure, so the equipment is an Italian coffee machine, and the grinding also requires a professional coffee grinder to be extremely fine.

Because when making espresso, the coffee powder must be packed hard to create resistance to the high-pressure hot water, so that the essence of the coffee can be truly extracted. Therefore, it is more sensitive to the degree of grinding. The more uniform the grinding, the denser the coffee powder will be after packing, and there will be fewer gaps, which can create balanced resistance to water, so that a cup of espresso can be successfully extracted.

If you use a moka pot to brew coffee, it is also more suitable to use ultra-fine powder, but the extraction will generally be over-extracted. Although a little oil can come out, the taste is bitter, and the enjoyment of the process is often greater than the taste itself. At the same time, you can't blindly pursue oil and grind the beans too finely, otherwise it will clog the exhaust holes and cause danger.

Because when making Italian coffee, you must pack the coffee powder hard to make it resist the high-pressure hot water, so that the essence of the coffee can be truly extracted. Therefore, it is more sensitive to the degree of grinding. The more uniform the grinding, the denser the coffee powder will be after packing, and there will be fewer gaps, which can produce balanced resistance to water, so that a cup of espresso can be successfully extracted.

(2) Fine powder: suitable for hanging ear

Fine powder is suitable for drip coffee. Many people think that drip coffee needs to be partially immersed in water, and should use coarser particles. In fact, it is mainly because the drip coffee is made entirely of filter paper, and the water output is large. Unlike hand brewing, which has a closing position, such as the three-hole filter cup commonly used now, it actually slows down the speed of water outflow, so drip coffee needs finer powder to increase the extraction area and extract more substances.

(3) Medium-fine powder (suitable for lightly roasted beans, Fuji Ghost Tooth 3.5)

Medium-fine powder ≈ white sugar (the most common white sugar in supermarkets is a little bigger than that). Generally, hand brewing will end up with medium-fine powder, because medium-fine powder is very commonly used, so if you love coffee, you should try your own coffee grinder more to find the medium-fine powder that suits you best.

(4) Medium powder (suitable for medium roasted beans, small Fuji Ghost Tooth 4)

Medium flour = granulated sugar (the largest particles of granulated sugar found in supermarkets are mostly of this size). Medium flour is slightly coarser than medium-fine flour, but the particles are not as large as coarse flour.

It is recommended that beginners use medium powder for hand brewing first. After all, it is not easy to produce extremely fine powder when grinding medium powder, and it is not easy to cause a lot of water to accumulate in the filter cup and soak the coffee powder due to unstable water flow control at the beginning, thus causing excessive coffee extraction. In addition, due to different personal tastes, you can try more between medium powder and fine powder to find the coarseness that suits you.

(5) Coarse powder (suitable for medium to dark roasted beans, small Fuji ghost tooth 4.5)

Coarse powder (similar to coarse white sugar, but finer than brown sugar) is suitable for use in siphon pots and French presses. Coarse powder is less likely to extract bitterness under high water temperature extraction. Similarly, it cannot be ground too coarsely, otherwise the taste will be bland if the extraction is insufficient.

The coarseness of the grinding determines the brewing method. Generally, the suitable extraction method for extremely coarse grinding is cold brew, the suitable extraction method for coarse grinding is French press, the suitable extraction method for medium-coarse grinding is drip filtering, the suitable extraction method for medium grinding is hand brewing or conical filter bowl drip filtering, the suitable extraction method for fine grinding is Italian espresso, and the suitable extraction method for extremely fine grinding is Turkish coffee.

In addition, a relatively uniform grinding degree is also important:

The finer the grinding degree, the stronger the bitterness, and the coarser the grinding degree, the lighter the bitterness. If the particle sizes are different, the degree of extraction of each particle will be different, which will also affect the taste of the coffee. Therefore, the coffee grinding degree can be the size of sugar particles, which is a grinding degree with a wider range of applications.

Coarse powder is suitable for high water temperature:

However, uneven grinding will bring out the sense of layers, so the extraction time should be controlled. Generally speaking, the shorter the cooking time, the finer the ground powder should be; the longer the cooking time, the coarser the ground powder should be. Therefore, the grinding degree should be proportional to the extraction time. The coarseness of the coffee grind will directly affect the length of the extraction time and the extraction rate. The finer the coffee is ground, the denser the powder layer, and more coffee powder particles are in contact with hot water, the greater the extraction resistance, the easier it is to extend the extraction time, and increase the extraction rate, and it is easy to over-extract.

On the contrary, the coarser the coffee is ground, the larger the gaps in the powder layer, the fewer coffee powder particles come into contact with hot water, the weaker the extraction resistance becomes, the less likely it is to extend the extraction time, and the lower the extraction rate, which can easily lead to under-extraction. Therefore, the finer the coffee is ground, the longer the extraction time and the higher the extraction rate; the coarser the coffee is ground, the shorter the extraction time and the lower the extraction rate. Under normal circumstances, the coarseness of the coffee is inversely proportional to the extraction time and the extraction rate. The coarser the powder particles are ground, the smaller the extraction resistance, the greater the coffee flow, the shorter the time it takes to extract a cup, the lower the extraction rate, and the lighter the taste.

The end~

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