Key points of knowledge about coffee bean grinding: the importance of grinding degree of coffee beans and coffee powder

The freshness of coffee beans is one of the factors affecting the grinding degree. Freshly roasted coffee beans because of the high activity of flavor components, do not need too fine grinding degree to emit enough flavor, so the grinding degree can be adjusted properly. At this time, if you still take a fine degree of grinding, coffee bean flavor components can be more divergent, but at this time it is easier to extract miscellaneous flavor and astringent taste, under the balance, it is more appropriate to use a thicker degree of grinding. On the other hand, with the decline of the freshness of coffee beans, it is necessary to use fine grinding to extract the flavor components that have lost their activity.

The change of humidity is also one of the factors affecting the degree of grinding. When the humidity is relatively high, the wet speed of the ground coffee powder is very fast, and there is already a slight humidity when filling the powder and cloth powder. If a fine grinding degree is used, the coffee flavor components have already reacted with the air with high humidity and become messy and impure, while the coffee powder is easier to be compacted and the extraction process is longer, which makes it easier to extract the bad taste and make the overall coffee taste muddy. Therefore, in the case of relatively high humidity, it is not suitable for a finer degree of grinding, it will be better to use a slightly thicker degree of grinding. On the other hand, in the case of relatively low humidity, coffee powder is ground out after contact with the air, the speed of oxidation reaction will also be accelerated, if the coarse grinding degree is used, then the coffee powder oxidation and flavor composition changes together make the extracted coffee taste will be less, lack of depth and mellow feeling, so the degree of grinding should be adjusted appropriately. Of course, after adjusting the degree of grinding, the corresponding adjustment of powder strength is also necessary.

Humidity factors play a role not only in sunny and rainy days, but also at different times of the day. Generally speaking, the humidity in the morning and evening is higher than that at noon, so according to the influence of humidity factors, the grinding degree should be thickened in the morning and evening, and finer at noon.

There are many other factors that affect the degree of grinding, including the roasting degree of coffee beans (although coffee beans used by Espresso should use a deeper roasting degree, but sometimes different roasting degrees may be used to roast formula beans for richer taste), blended recipes, and so on. All of the above are the most common and can be mastered by baristas. The previous sections are all about the adjustment of the basic factors in the production process in order to meet that taste standard on the premise of understanding the good taste of Espresso (see the taste of Espresso). There are many places in the world of Espresso that we don't fully understand, and we would like to explore this wonderful world of coffee with you.

Generally, when buying coffee beans, you can tell the shopkeeper the granularity and brewing method of the coffee powder you need, and ask the shopkeeper to grind it instead.

Because different cooking methods require different grinding sizes, it is important to establish a good interactive relationship with the stores you buy coffee beans, so that the sales staff will provide you with the freshest and best quality coffee beans, or constantly adjust the grinding granularity for you to grind the ideal coffee powder for you.

Coarse granularity: about the size of planed sawdust, similar to flaky particles, suitable for filter pots, can also be placed in tea bags, placed in pots and brewed with hot water.

Medium granularity: about the size of coarse sugar, suitable for hand filter cup and hand filter cloth. Medium fineness: about the size of No. 2 sugar, suitable for electric coffee maker, siphon and mocha pot.

Fine granularity: about the size of quicksand on the beach, suitable for Italian coffee maker and water drop iced coffee. Finest granularity: about the size of too white powder, suitable for use in Turkish pots.

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

1. The degree of grinding suitable for cooking method should be selected.

2. The temperature produced during grinding is lower.

3. The powder should be uniform after grinding.

4. Grind before cooking.

No matter what kind of grinder is used, it is bound to generate heat by friction during operation. However, most of the fine substances are highly volatile, and the heat of grinding will increase the speed of volatilization, allowing the aromatic alcohol to be lost in the air first.

After grinding, the cell wall of coffee beans will completely disintegrate, which means that the area of contact with air will increase a lot, all lines of defense to protect freshness will be completely removed, and the rate of oxidation and deterioration will become faster, which will make the coffee lose its flavor within 30 seconds to 2 minutes. Therefore, the author strongly suggests: do not buy coffee powder, it is best to buy coffee beans, and grinding before drinking, grinding should be brewed quickly.

Before the invention of the bean grinder, people used stone pestles and bowls to grind coffee beans. A doctor abroad once experimented with this ancient tool and compared it with a modern bean grinder. It is said that the coffee powder made from pestles and stone bowls is the most mellow. According to logical reasoning, the pestle cracked the coffee beans naturally by impact, which should be the least likely to damage the cell wall and best retain the excellent substances of coffee. However, in modern life, it is almost impossible for people to use pestles and stone bowls to grind coffee, so it is particularly important to choose a good bean grinder.

* the importance of uniform grinding

Once the coffee beans are ground too fine and the water comes into contact with the surface of the coffee powder too much, too many unnecessary impurities will be extracted, even bitter beans will come out; but if the coffee is ground too thick, the delicacy will still be hidden deep inside, where the hot water can not be touched. The coffee brewed does not have enough aroma.

When brewing Italian espresso, we must make efforts to fill the coffee powder to make it resistant to high-pressure hot water in order to really extract the essence of coffee. Therefore, it is more sensitive to the degree of grinding, the more uniform grinding, the more compact the coffee powder, and less space, can produce balanced resistance to water, so that a cup of Espresso can be extracted successfully.

Lapping degree reference

As far as the average consumer is concerned, after buying coffee beans, bean grinders and coffee machines, only two variables, grinding degree and brewing time, need to be paid attention to. Among them, brewing time is easier to understand, and you can get the hang of it quicker. However, the effect of grinding degree on coffee quality is more subtle, and there is a lot of room for discussion. The range of grinding degree of powder from fine to coarse can be divided into the following types:

61 Turkish Turkish Grind is suitable for Ibrik pots, where coffee is boiled. It originated from the Turkish people, and is often used in some countries in southern Europe. In Taiwan, this method of brewing is rare.

61 espresso grinding (Espresso Grind) is suitable for the use of espresso machine, and is more sensitive to the fine degree of grinding.

6 1 fine grinding (Fine Grind) is suitable for mocha pot or dripping filter cup.

6 1 medium grinding (Medium Grind) is suitable for trickling filter cup or air stopper.

61 rough grinding (Coarse Grind) is suitable for filter kettle.

There are many ways to extract coffee, and the various utensils we use for extraction are of different grades. Many beginner enthusiasts like to spend most of their equipment budget on high-end coffee pots (such as siphon, French pressure, hand punch and filter cups, etc.), including expensive hario cradle sets. But the bean grinder casually buys a very cheap hand mill or shanzhai electric mill, bean chopping machine and so on. But take the most popular hand-punch extraction method as an example, hand pots with a general price of more than 100 or even dozens of yuan can also be trained to obtain more stable and finer water flow (even some of them are easy to use). Filter cup resin is not necessarily worse than glass or copper filter cup, sharing pot is even more casual, hand punch frame is optional (of course, to a certain extent, high-end equipment will naturally give play to its due advantages). Then we began to study the coordination of various data of brewing techniques, such as grinding scale, water temperature, how to stew, how to control water injection, the ratio of water to powder, and the extraction time. The above is important, but many people ignore that the grinding quality of the bean grinder is beyond our control through practice. some even take it for granted that the extra money paid for a good mill is not proportional to the improvement of coffee and insist on using an extremely low-end bean grinder. However, we do not know that the grinding quality of coffee beans is the top priority of a cup of coffee. So I suggest: "No matter how poor you are in playing coffee, you can't be poor in a bean grinder, and no matter how rich you are, you don't have to be rich in a coffee pot." I even saw a newly opened cafe using kalita900ml copper pot for hand flushing pot, with chemex and kone metal strainer, hario electronic scale with timing function, and bean grinder hario mss-1b. I said it's not too much to suggest him to change the mill and set up a shop with a little Fuji. The boss replied, "I don't think it's necessary. This mill works well. What is little Fuji?" Never heard of it. " I'm speechless. This is a real story. And I've been in a similar situation more than once or twice.

Yejia Xuefei is a kind of coffee that most coffee lovers like. I have been addicted to the sun for nearly a year, and recently I suddenly found that I haven't washed Yega for a long time. So I washed the G2 with some Kochel water, and immediately after baking, I made a cup (the bean grinder equipped with the baking place is Pegasus 207n). In one sip, I felt it was a touching taste and it was amazing. It is rare to see such a performance of the water-washed Yega G2. When I went back to my residence in the evening, I made another cup full of anticipation after dinner, but the effect became mediocre (the bean grinder equipped with Solis solis166). Before that, I couldn't figure out why the freshly baked beans tasted so good, but after one night, or even a few hours later, they tasted completely different. (often because of the shortage of time, we rush home with beans after baking. Pegasus only occasionally have enough time to bake and try beans.) After this huge difference in taste, I decided to make a formal comparison. In the past, it was clear that the bean grinder had a great impact on the product, but never experienced such a huge gap.

This experiment only compares the existing bean grinder in my hand, which are: 1, Taiwan Yang Jiafei Horse 207n (Ghost teeth), 2, solis166 (Cone Dao), 3, mazzer superjolly (flat Dao) may not be suitable, but it is here anyway, whether I use it or not, so send it as the representative of flat Dao! It should be noted that using these three grinders is not a bean grinder representing the three types of cutters, but a hungry choice.)

First of all, the three mills are adjusted to a relatively close grinding scale.

In order to avoid various unstable factors in the brewing process as far as possible, the comparison apparatus chooses Ailo pressure.

Brewing mode:

Coffee powder: 15g

Water temperature: 88 degrees

Water injection: try to control the injection of 250ml hot water at 1 minute.

Press: try to control the coffee completely into the sharing pot within 45 seconds.

With the addition of details such as screwing the cap and reversing the Philharmonic pressure, the whole extraction process is controlled in about 2 minutes.

In order to make the flavor more complete and more prominent, and to facilitate my limited level of taste, the coffee beans were washed with Yega Xuefei and Kocher G1 in this test.

Comparison results:

1. Yang Jia Fei Ma 207n (Ghost teeth)

The fragrance of the imported flowers is strong, the acidity is moderate and soft and comfortable.

High sweetness in the middle, with an obvious ripe fruit sweetness (plums? Melon? Probably so, the specific indescribable, my taste level is limited)

The tail segment is slightly anti-acid, at the same time, the acid has a honey-like sweet feeling.

The overall taste is round and smooth, and the sweetness lasts for a long time after drinking.

If you want to make an analogy to the flavor intensity, you should know more about the sun Aricha. It is not too much to say that it is very close to the fruit bomb such as Aricha when washing Kochel G1 flavor. (of course, the flavor is different, but the flavor prominence is similar).

2. Solis166 (conical knife)

The fragrance of the imported flowers is weak and the acidity is also weak.

The importance of the grinding degree of coffee beans and coffee powder (the thickness of coffee powder) the thickness of coffee powder

Yimutian boutique coffee farm in Yunnan.

The sweetness in the middle is still high, but without the sweet aroma of 207n, the aroma of ripe fruit becomes faint.

At the end of the day, there is no sweet sense of honey, and finally there is a sense of astringency.

The overall taste is relatively thin compared with 207n.

3. Mazzer super jolly (flat knife)

The fragrance of the imported flowers almost disappears, and the acidity is the most obvious of the three mills, but this acid appears to be stiff.

The middle sweetness becomes less obvious affected by acidity, the fruit aroma is very weak, and there is a certain degree of bitterness.

The last part disappeared soon after showing a little sweetness, but there was no astringent feeling.

The overall taste is also relatively thin.

In the end, I think the ranking is as follows:

1. Yang Jia Fei Ma 207n (Ghost teeth)

2. Solis166 (conical knife)

3. Mazzer super jolly (flat knife)

After this comparison, I am determined to start with little Fuji. In the past two or three years of real contact with coffee, perhaps I have missed out on a lot of delicacies because of my desire for a small bean grinder and a moderate price. (of course, it is not that only a ghost tooth grinder can produce a good product. But at least know the importance of the bean grinder to a cup of coffee.) whether it is a single product or Italian style, making a good cup of coffee, the importance of the bean grinder is far greater than the brewing equipment itself. I hope those of you who have read this article will not miss the delicious food that should belong to you again if conditions permit. Finally, there is the saying, "No matter how poor you are, you can't be poor in a bean grinder, and no matter how rich you are, you don't have to be rich in a coffee pot."

I. the relationship between grinding thickness and extraction time

The finer the coffee is, the denser the powder layer is, there are more coffee powder particles in contact with hot water, the extraction resistance increases, it is easier to prolong the extraction time, and increase the extraction rate, so it is easy to over-extraction.

On the contrary, the thicker the touch is, the larger the gap in the powder layer is, the less coffee powder is in contact with water, the weaker the extraction resistance, the lower the extraction time and the extraction rate, so it is easy to lack of extraction.

Therefore, the veteran will control the extraction time according to the size of the powder. If the powder is fine, the extraction time will be slightly shortened. If it is coarse, the extraction time will be slightly prolonged.

Second, deep baked beans are slightly thicker and shallow baked beans are slightly thinner.

In addition, before determining the grinding degree of coffee beans, the veteran will first judge the color and oil production of cooked beans, the lighter the roast, the less easy to extract, then use a little fine grinding. The deeper the baking is, the easier it is to extract, so slightly rough grinding is used.

Therefore, the depth is thick and shallow. (however, it should not be too coarse or too fine, which will cause abnormal extraction and affect the flavor of coffee)

3. The grinding degrees of all kinds of bubble cooking methods from coarse to fine are as follows:

French filter press (thick)

Electric trickling filter pot (medium and thick)

Hand flushing pot, siphon pot, desktop smart filter cup (moderate)

Mocha pot (medium and fine)

Espresso (fine)

Turkish coffee (very fine)

There are two things that must be corrected!

1. The amount of extracted material is not due to the resistance caused by the size of the gap in the powder layer. If it is really because the rough grinding resistance is small, then do Italian, compared with light pressure and fine grinding, with rough grinding and heavy pressure, why can the consistent flow rate be achieved? Don't simply assume that the pressing powder can resist the pressure of 9 bar. If it is really possible to use the powder force to resist the pressure of 9 bar, think about the speed of the rough mill.

For the difference in flavor between fine grinding and rough grinding, you can refer to the view that coffee extraction only extracts the surface of powder balls mentioned by Dr.illy and some coffee masters.

2. The soluble substance extracted is related to the thickness, but the extraction rate is not absolutely equivalent to this. Otherwise, why would many competitors increase the amount of powder to reduce the extraction rate through relatively fine grinding force and slightly fine grinding?

As for the relationship between extraction rate and concentration, it is recommended to look at the relevant articles, such as Zhe's.

The fineness of coffee powder used to make siphon coffee is thicker than that of espresso. If you rub your hands together, you should feel a little grainy. If you use a professional electric bucket grinder, the effect is of course the best, you can simply and quickly use different scales of coffee powder to try to compare, to find out the most suitable brewing method, coffee variety thickness.

There is a kind of grinder on the market that costs about 200 yuan and the motor blade is violently broken. In the past, there were some multi-function juicers with more than 100 yuan, and they also had similar functional components. This kind of so-called grinder, grinding is uneven, not "grinding", but "blow". The powder is very uneven and expensive, so try not to use it. Especially siphon coffee.

When making siphon coffee, use a hand grinder, which is more emotional and can meet the demand. Adjust the fineness before use, and control the fineness of the coffee by adjusting the gap between the rotor and the powder. If the beans fall too fast, or if they remain unchanged for a long time, they all need to be adjusted. After boiling water, start grinding, so that the water in the siphon coffee pot can be ground before it boils, so that the coffee powder sends out aromatic substances in the air for the shortest time and can best maintain the original flavor of the coffee.

Siphon coffee focuses on taste and aroma. Therefore, the grinding speed can not be too fast, too fast and easy to overheat, overheating will accelerate the volatilization of aromatic substances in coffee powder; nor too slow, coffee powder exposed to the air for a long time, of course more volatilization; to contact the progress of heating, master a moderate grinding speed; generally turn around after a few laps.

Source: Wen Honggang's blog