August 17, 2022

There are a wide variety of electric coffee grinder machine on the market, and many beginners of single-origin coffee do not know how to choose a grinder. What affects the grinding degree is the grinding disc in the bean grinder. Common grinding discs include flat knife grinding disc, vertebral knife grinding disc and ghost tooth grinding disc. What are the differences between these three grinding discs, and what are their characteristics? This time, I will talk to you about the differences between the three types of grinding discs.

There are two main types of electric coffee grinder machine: one is an Italian-style coffee grinder machine, and the other is a single-product grinder. The difference between the two is the size of the ground coffee.

The biggest feature of Italian-style coffee grinder machine is that the grinding is extremely fine, the speed is fast, the cutter head is large, and the uniformity is a hard indicator for judging whether the coffee grinder is good or not. The grinder is not as fine as an Italian grinder.

Compared with the hand grinder, the single product grinder is more uniform and faster, and the coffee grinding process can be conveniently completed in just one button. Usually has more grinding gears, wide adaptability, and good adaptability to various coffee extraction equipment.

According to the structure of the grinding plate, it can be divided into three categories: flat knife, cone knife and ghost tooth. The grinding plate determines the performance of the grinder and also determines the price of the grinder.

 

Flat Knife

 

Working Principle

It consists of two upper and lower cutter discs, and the base is fixed on the motor. When the motor starts, the upper and lower cutter discs are rotated to produce cutting action. When the coffee granules fall from the middle, the rotating cutter head at the bottom will rotate the coffee beans to the periphery, pushing the coffee beans into the toothed cutter part for grinding. The upper and lower cutter heads of the flat knife are arranged in parallel, so the coffee beans need to rely on the force of the bottom cutter head to push the coffee beans into the cutter head. Therefore, the weight of the coffee beans placed on the top will affect the uniformity of the coffee beans entering the cutter head. In addition, the number of collisions between coffee beans increases due to pushing, which in turn leads to an increase in the proportion of fine powder produced. This is the reason why the particle uniformity of the common flat knife grinder is slightly worse and the fine powder is more. Improve the concentration and extraction rate of coffee liquid in a short time, so that the aroma of coffee can be significantly improved in a short time.

 

Suitable for

Single origin coffee.

 

Advantage

The positioning is relatively clear, and the quality of the product is proportional to the grade of the grinder and the diameter of the grinding disc.

 

Disadvantage

The uniformity of the grinding particles is slightly poor, and there are many fine powders. Because the blade of the flat knife grinder cuts the coffee beans at will, it is easy to cause insufficient or excessive extraction of the coffee powder during brewing. In addition, the friction of the flat knife will generate heat, especially When the flat knife grinder is working for a long time, there will be a noticeable burnt and bitter taste.

 

Cone Knife

 

Working Principle

Place a conical cutter head at the bottom, and then cooperate with the outer ring cutter head for grinding. After the coffee beans fall from above, the coffee beans will be pulled down with the rotation of the conical cutter head, resulting in the grinding action. down relationship. Therefore, the particles do not need to be pushed out of the coffee. Compared with the flat knife grinder, the number of collisions between particles will be much reduced, so the proportion of fine powder produced by the cone knife will be much lower than that of the flat knife, and the coffee grinding uniformity will be reduced. will increase substantially. The particles ground by the cone knife will be close to granular, which will cause the water absorption path of the coffee particles to become longer, and it will take a longer time for the inside to contact the water. Therefore, the soluble substances released by the cone knife particles will be less at the initial stage, resulting in the concentration in a short time. Not too high, and at the same time, because of the granular shape, the xylem absorbs less water, making it less likely to produce off-flavors and astringency, even under prolonged extraction.

 

Suitable for

Espresso, Turkish, French Press.

 

Advantage

Compared with the flat knife grinder, the cone knife grinds more uniform particles, produces less fine powder, and is not easy to produce miscellaneous and astringent flavors, which improves the layering of the coffee flavor.

 

Disadvantage

The near-granularity of the ground particles results in a longer path for the coffee particles to absorb water, and it takes longer for the interior to come into contact with the water.

 

Ghost Tooth

 

Working Principle

The operation mode of the ghost tooth grinder is similar to that of the flat knife grinder. The coffee beans fall from the top, and the coffee beans are ground with the rotation of the cutter head. The particles do not need to be pushed. The flat knife has much less fine powder, but the ghost The coffee powder particles of the tooth grinding are more round, and the ratio of coarse powder and fine powder is more uniform.

 

Suitable for

Single-origin coffee, or if you want to get a coarser coffee powder.

 

Advantage

Better balance and thickness, more uniform grinding, cleaner and fuller than flat and tapered knives.

 

Disadvantage

It is impossible to grind finer coffee grounds and cannot meet the grind degree of espresso.

 

How to choose a grinder that is more suitable for you?

 

1. When you need to obtain a higher concentration of coffee in a short time, the flat knife grinder is a good choice. High concentration will also make the aroma rich, so the aroma of the flat knife will be much more obvious than that of the cone knife. The famous grinder EK43 is a flat knife.

2. When a better taste is required, the granular coffee powder produced by the cone knife can reduce the time when the xylem is in contact with water. Although the aroma is not as obvious as that of the flat knife, the taste is still better even if the extraction time is prolonged. The famous hand grinder is the German Commander c40.

3. The performance of the ghost tooth grinder is the best in all aspects, and the flavor of the product is more moderate. In addition to the key factor of uniformity, the ghost tooth grinder is more suitable for testing the flavor of coffee beans.