Explain the grinding equipment of coffee beans: bean grinder

Many people would rather spend a lot of money on other coffee-making utensils than configure a better grinder. In fact, the size, shape and uniformity of the ground particles will directly affect the extraction rate of coffee and further affect the quality of the whole cup of coffee. To some extent, the grinder is even more important than the coffee maker itself. If the equipment is not good, we can make up for the defects of the equipment through constant practice and skillful techniques, while the quality of the grinder is not high, but it is powerless through practice. So when buying coffee utensils, I recommend that you spend at least 25% of your budget on the grinder, or even 50%.

From a mechanical point of view, it can be broadly divided into two categories:

1. Hand bean grinder: almost all of them are single bean grinders.

2. Electric bean grinder: Italian style and individual products are available, but they are all independent.

What is a good bean grinder?

A good coffee grinder is mainly reflected in the following aspects:

1, the uniformity of grinding: uniformity is the most important thing to judge the quality of the grinder, uneven grinding will cause uneven extraction, often some parts of coffee powder have not been fully extracted, but some parts have been over-extracted. finally, the whole cup of coffee has a bad smell. One of the most common problems is that fine powder will be produced during rough grinding, resulting in bitter coffee. Although there will be fine powder phenomenon in even the best grinder, the phenomenon of fine powder in some low-end bean grinders will be especially obvious.

2. Heat generated during grinding: as mentioned in the previous article, the aromatic substances in coffee powder are very volatile, and the heat during grinding will accelerate this volatilization. A good grinder can control the heat within a certain range by reasonable torque. However, if people drink their own coffee at home, they only grind a small amount of beans, and the effect of fever is negligible.

3. Grinding speed: needless to say, the more time-saving and labor-saving, the better. However, it should be noted that some low-end grinders simply increase the speed to improve efficiency, which will cause a large amount of heat as mentioned in the second point. A good bean grinder generally achieves the balance of heat production and efficiency through low speed and high torque.

PS: the characteristic of hardware products is one price per cent. If you want a good bean grinder, a certain amount of investment is essential.

Grinding disc classification

Since it belongs to the grinding machine, then its core component must be the grinding disc; now there are roughly three kinds of grinding plates on the market:

Flat knife grinding plate

That is, the parallel cutter head, when using, the coffee beans are pushed and ground from inside to outside. It is easy to heat up when rotating at high speed, but the uniformity is better than that of cone knife.

Conical cutter head

That is, the tapered cutter head, when in use, the coffee beans are ground from top to bottom. The grinding speed is fast, the heat is low, the uniformity accuracy is not as good as the flat knife, and the taste of the product is richer.

There is also a saying that the cone knife is more uniform, but in practice, I tend to think that the flat knife uniformity of the same grade grinder is slightly better. )

In fact, it is difficult to say whether the flat knife or the conical knife is better or worse, but more importantly, it depends on the design of the grinding plate. The two kinds of cutter head structure have their own excellent products, and the high-end bean grinders worth more than 10,000 yuan are also used. Most of the hand mills that are easy to buy in China are conical knives, while electric grinding has both flat knives and conical knives.

Ghost tooth

In addition to the two most basic cutterhead structures of conical cutters and flat knives, in order to overcome their respective shortcomings, there are all kinds of flat knives, the combination of conical knives, and ghost teeth developed on the basis of flat knives, all of which are in order to better balance the problem of heat and uniformity. In addition, we should also pay attention to the double-blade structure similar to the juicer used in some low-end electric mills, which is jokingly called "bean chopping machine". The uniformity and heat are not very good, so try not to buy it.

Compared with the flat knife, it has less heat and high evenness, and it is mostly used for electric grinding, but it can also be seen occasionally on some foreign antique hand mills.

Factors affecting grinding quality

Different coffee production methods have different requirements for the grinder, such as Espresso, which requires the finest degree of grinding, and previously mentioned that the volatilization of aromatic substances is very fast, so it is required to finish the grinding quickly, which is incompetent for most hand mills, so it generally requires more professional electric grinding. If you choose the method kettle to make, the filter screen is thick, and the corresponding particles that need to be ground are also relatively thick, which also increases the requirement for the grinder, otherwise a large amount of fine powder is mixed in the coarse powder, in addition to causing uneven extraction, the fine powder will also make the coffee turbid through the filter.

The fixed form of the axis is also an important factor affecting the grinding quality, many cheap hand mills to save costs, only one end of the axis is fixed, so the axis will be unstable, resulting in large axis sloshing, uneven thickness, and the thicker the grinding, the more obvious this phenomenon is. On the other hand, the price of the hand mill with double fixed axis is doubled, which is about one thousand yuan. So don't worry about the fixed problem of the axis, or the ingenious one can modify the cheap mill by himself, and the relevant tutorials can also be found online.