"about fine powder" coffee should be sifted? Will coffee taste better when treated with a sieve?

A long time ago, someone would use a sieve to sift the ground coffee powder before starting to cook it. The main reason at that time was that the quality of the coffee mill was not high enough and there was more fine powder. Simply sifting the fine powder could avoid the miscellaneous smell caused by the excessive essence of the fine powder in the coffee brewing.

In the past, when I went to a coffee shop run by the Japanese, I saw that they would sift through the fine powder slightly after grinding. I haven't seen them do this step in more than a year. I don't know why.

Australia's Matt Perger, the winner of the 2013 World hand Coffee Competition, played in the final with a sunscreen. But he talked about it from the theory of brewing and cooking. In the past, we recognized that the extraction rate of coffee brewing was between 18% and 22%, but Matt told the referee that the extraction rate of the coffee he was going to make reached 23%, but it was still delicious. Because he will use the net to dry the fine powder and then cook it.

Matt believes that in the past, we recognized the 22% extraction rate because we did not take into account the interference of fine powder in coffee grinding, which finally affected the taste of the whole cup of coffee. (when watching the video of the game at that time, he immediately inferred that he would win the championship in the end, because WCE's competitions have always respected contestants who have opinions and ideas that can have an impact on the industry.)

John private coffee did a small experiment, the role of the screen on the impact of the final product is quite satisfactory, make a small summary!

For friends who often drink coffee at home, it is estimated that they will be no stranger to all kinds of bean grinders. At present, there are Mazzer, Little Eagle, Pegasus, solis 166, rancilio rocky, Yang Family 900n, Big Fei Eagle and so on. Each mill has its own advantages, some are cost-effective, some are functional. However, no matter which one, it seems that it can not solve the problem of fine powder when grinding coarse powder at this stage.

Many friends seem to have an illusion that it is easy to grind, but it is not easy to grind fine, but they do not realize that it is very difficult for grinding powder to achieve uniformity, or to mix less fine powder. And these fine powders are the source of miscellaneous smell or over-extraction in the process of brewing (hand flushing, siphon, pressure, etc.).

So today, we use the newly bought 30-mesh sieve to sift through the ground powder and want to taste a cup of coffee with a pure taste. (note: 30 mesh means 30 holes per square centimeter, which is a standard unit.)

Coffee beans: Kenya AA uses bean grinder: Mazzer Super Jolly

Baking degree: medium and deep brewing method: V6001 filter paper hand flushing

Amount of powder used: 26g

On the left side of the picture below is the coffee that does not pass through the 30-mesh screen, and on the right is the fine powder that has passed through the 30-mesh screen.

Photo Source: John Private Coffee

Close-up: fine powder with 30 mesh sieve vs 30 purpose coarse powder

Photo Source: John Private Coffee

Use the sifted 30 mesh powder to make hand flushing to get about 200 milliliters of coffee. This cup of coffee completely presents a different taste, seems to be a twin sister with the original Kenya, the original wild calm is much softer, very clear in the mouth, the acidity is obvious but not restless, a touch of sweetness mixed with rich flower aroma, if you do not taste carefully, it seems that the bitter taste has dissipated, only you in the aftertaste, the faint bitterness will appear, this bitterness and the overall sweetness take care of each other, very harmonious.

Photo Source: John Private Coffee

Of course, the removal of fine powder, in fact, this cup of coffee also lost something, first of all, the concentration is worse, mellowness and persistence are also reduced a lot. But it is estimated that what many coffee lovers cannot accept is the "waste" caused by sieving powder. As can be seen in the following picture, sieving powder will sift out about 1 / 4 of the powder, although the left and right sides are the same powder. But the left side can be "clear" and the right side may be "dirty".

Photo Source: John Private Coffee

In fact, doing this small experiment does not mean that everyone has to sift out all the fine powder. It is estimated that in daily life, no one will be so "accurate", and there is really no need to be so "accurate". I just want to say that the grinding degree and evenness of the powder will affect the taste of coffee. You can try different grinding degrees to make the same kind of beans show different tastes in your mouth. (source: @ John Private Coffee blog)

What causes it?

Because the sieve powder can consider the over-fine powder, so that the particle size is basically the same, achieving a relatively uniform extraction, so each particle size (each coffee powder) conveys roughly the same taste. The final cup of coffee is very smooth, clean, layered coffee.

How important is a bean grinder to make a cup of coffee?

In the coffee industry, there is a definition: bean grinder is more important than Italian machine. Professional coffee shops still know this, so if you want to make a qualified boutique coffee in the family, the coffee grinder should attract enough attention. Making coffee itself can be affected by many factors, such as coffee powder, proportion and water temperature.

For example, the powder ground by a poor quality bean grinder is uneven in thickness, large and small, and when a stream of hot water rushes down, within three minutes, the large particles have not been extracted, and the small particles are excessively extracted; the coffee powder in the container is unevenly distributed, and the side with more coarse powder will be extracted too much at high water temperature; the side with more fine powder will be extracted incompletely at low water temperature. This concept is the same as all methods of making coffee, no matter how much coffee needs to be ground. Excessive extraction will make the coffee numb and astringent on the tip of the tongue, and incomplete extraction will leave the coffee with very little flavor and only acid.

So how important is a bean grinder that can grind coffee powder to almost every grain.

So what is a good bean grinder? Some knowledgeable friends will say: grind even bean grinder. In fact, a completely uniform coffee grinding does not exist. At present, the coffee powder produced by any coffee grinder is composed of coarse powder, medium-fine powder, fine powder and very fine powder. These coffee powders of different particle sizes play different roles in the process of coffee extraction, some are used to form alcohol thickness, and some are used to show flavor. So even if there is a completely uniform bean grinder, the flavor of the coffee is very mediocre. If you have the opportunity to use different mesh sieves, the ground coffee powder will be sifted and then made, the effect will be clear at a glance.

Another point is the other reactions produced by the bean grinder when it is in operation: heat generation, residual powder. All these will affect the quality of grinding.

The key points of coffee grinding are as follows: first, the degree of grinding should be uniform; second, produce as little friction heat as possible; third, avoid fine powder as far as possible; fourth, select the degree of grinding suitable for extraction.

(1) the degree of grinding should be uniform

The deterioration of coffee taste caused by uneven grinding degree is fatal. The coffee extraction rule is: "the finer the grinding degree, the stronger the bitter taste, the weaker the acid taste, the thicker the grinding degree, the weaker the bitter taste, the stronger the acid taste."

(2) minimize the generation of friction heat

When the bean grinder is working, it will generate heat. The heat generated by friction will significantly damage the aroma and flavor of coffee. The faster the speed of the bean grinder, the greater the calorific value.

(3) avoid fine powder as much as possible

The influence of fine powder on coffee extraction is even greater than friction heating, the high temperature and static electricity produced by the bean grinder will make the fine powder adhere to the inside and channel of the bean grinder, and the oxidized and rancid residual powder will be mixed into the new coffee powder during the next grinding, resulting in taste deterioration, not only the coffee liquid is muddy, but also brings unpleasant bitterness, astringency and even bad smell.

Therefore, the correct choice of bean grinder is very important!