Professional coffee roasting knowledge coffee grinder

There are different brands and models of bean grinder, and the grinder which can adjust the thickness of grinding bean is ideal. When grinding with a bean grinder, don't grind too much at one time, just enough for one use. Because the longer the bean grinder is used at one time, the easier it is to heat up, which indirectly causes the coffee beans to be heated and leads to the loss of aroma, thus affecting the aroma of the coffee.

Coffee beans contain oil, so the bean grinder must be cleaned after grinding, otherwise the grease will be fouled and will smell stale after a long time, and even the most advanced beans will be ground into a strange-smelling powder. After each use of the bean grinder, be sure to wipe the blade table with a wet towel and clean the plastic top cover with warm hot water. However, we should pay special attention to the American popular flavored coffee, the added flavor is strong and strong, and will remain for a long time. Therefore, it is best to put two spoonfuls of sugar in before cleaning to beat the flavor. Of course, it is better for a grinder to grind only the same kind of beans, so that there is no problem of mixing.

(1) Propeller bean grinder

This kind of bean grinder uses a motor to turn a propeller blade to grind coffee beans into powder. Coffee beans will be chopped to pieces and a lot of flavor will be lost. Therefore, this kind of propeller bean grinder is not commonly used. However, because it is cheap, small and does not take up space, some homes and offices still use it frequently. The propeller bean grinder mainly has the following disadvantages:

1. High temperature is formed during grinding.

Compared with other bean grinders, this kind of bean grinder has the fastest speed and is easy to form high temperature after high-speed friction with coffee beans. However, the boiling point of aromatic substances is very low, so the aroma of coffee will be lost in the high temperature of the grinding process, thus discoloring the coffee.

2. Uneven grinding

This kind of grinding opportunity will cut the coffee beans randomly, and the powder formed is either too thick or too fine (too fine coffee powder will produce bitterness), which is difficult to be uniform. Especially in a large number of grinding, often floating on the top of the beans, easy to produce too thick coffee grains. This tends to form a random distribution, with a high proportion of too fine and too coarse powder particles.

In order to overcome this disadvantage, a small amount of grinding can be used, and hold the bean grinder by hand, and shake the lid up and down with your thumb, so that the blade can be cut evenly to the coffee grains.

3. Form a block

When grinding beans, the high-speed spiral blade will make the coffee powder form a whirlpool, but because the centrifugal force is too large, it will make the ultra-fine powder form lumps and stick around, which will prevent hot water from soaking coffee averagely, resulting in uneven extraction.

4. The degree of grinding cannot be set.

This kind of bean grinder does not have the function of setting the grinding degree, so it can only be determined according to the grinding time. The general grinding time is about 6-10 seconds, which is suitable for filter kettles, follicular cups and air stoppers. However, espresso requires very fine grinding, which may take more than 20 seconds, when the friction temperature will continue to evaporate the aroma of the coffee.

5. Dangerous switch design

In design, this kind of grinder usually uses the pressure of closing the lid to start the switch and rotate the spiral blade. When putting beans or cleaning, if you accidentally press the switch and the finger is right near the blade, the consequences will be unimaginable. It is suggested that the plug should be unplugged at ordinary times, then plugged in before grinding the beans, and unplugged immediately after use; when handling and cleaning, the power supply should also be cut off. In addition, the plastic lid above can be cleaned with water, but the inside and outside of the fuselage can not be stained with water, can only be wiped with a dishcloth.

(2) hand-operated bean grinder

For more than 100 years, the design of the hand-operated bean grinder has hardly changed, and even the latest models tend to be classical and elegant. This kind of bean grinder needs to rotate the rocker by hand, turn the iron sharpening knife inside, crush the coffee beans into a fine powder and drop them in the box below. Strictly speaking, the internal sharpening knife is not a knife, because it does not have a sharp blade or sawtooth, but a tapered grinding iron with an angle. It grinds the coffee beans by rolling, which is similar to the ancient mortar and pestle, and can best retain the aroma of the coffee.

Although it is a bit hard to use a hand bean grinder, and the speed is not fast, it can grind coffee powder with uniform particles, coupled with the lowest friction temperature during grinding, so it is not easy to destroy the delicacy of coffee. It is very suitable for drip filter and drip bubble brewing methods. In addition, the hand-held bean grinder makes the least noise and has always been a favorite of coffee brewers.

The hand-operated bean grinder usually has a ring-shaped knob between the rocker and the main body, which can grind down to produce finer coffee powder. this bean grinder can grind coffee powder of medium to fine size, but it is impossible to grind very fine powder. so it's not suitable for grinding espresso powder.

(3) Sawtooth bean grinder

The saw-tooth bean grinder can grind uniform coffee powder quickly and steadily, but the price is higher.

The operation method of this kind of bean grinder is quite simple, as long as you follow the instructions on the instructions, it can be easily used. Generally speaking, it has two setting functions, one is the grinding degree setting, the other is the grinding time setting. The degree of grinding is mostly expressed in Arabic numerals, and the smaller the number is, the finer the grinding is. Some clearly indicate the grinding range of various brewing methods. For example: Filter, Espresso, etc. The range of Filter is suitable for drip and follicle brewing methods, while Espresso is suitable for espresso, and the instructions will also specify the application of various grinding degrees.

The bean grinder has a funnel-shaped container containing unground beans. The longer the time is set, the more beans will fall into the grinder, the more coffee will be ground. As the fresh-keeping effect of the box is not good, it is recommended to drink as much as possible and drink it after grinding it at one time. Other beans can be stored in vacuum cans or fresh bags and can be grinded next time.

1. Types of sawtooth bean grinders

There are two types of sawtooth grinders: one is a planar sawtooth knife and the other is a three-dimensional conical sawtooth knife.

(1) Planar serrated cutter

The flat machine consists of two annular blades with sharp sawteeth on the circumference. After starting, the coffee beans are brought between the blades and are instantly cut and crushed into fine particles. As far as household appliances are concerned, the flat sawtooth grinder is the closest to a commercial large bean grinder, similar to a bean grinder in a coffee shop.

(2) three-dimensional conical serrated cutter

The tapered bean grinder is composed of two pieces of tapered iron, the surface of which is covered with serrated teeth. The gap between the two pieces of iron is where the coffee beans are ground into powder. The conical serrated cutter produces the lowest friction temperature and can form uniform grinding. Both commercial machines and manual bean grinders use conical serrated cutters.

2. Matters needing attention in the selection and purchase of sawtooth bean grinder

The bean grinder with higher power has faster grinding speed, the coffee powder stays in the sawtooth room for a shorter time, and can grind the low-temperature coffee. Generally speaking, the power of bean grinder is between 70 watts and 150 watts, and the higher the power, the better.

The grinding effect of some coffee grinders is very poor, and the coffee powder is not fine enough. When brewing espresso, the extraction is insufficient, making the finished product tasteless, so for grinding espresso, special attention should be paid to the precision of the grinder to make sure that it can grind a uniform and meticulous coffee powder, so as to brew a good coffee.