Grinding degree of hand-brewed coffee powder thickness standard hand-brewed coffee grinding scale adjustment parameters are appropriate

Whether it is online Taobao shop, Wechat, or offline stores, there will be a lot of friends ask about the grinding degree of coffee powder. And Qianjie Coffee's answer is often those six words-"as thick as sugar".

How thin is the fine sugar?

This for some coffee rookies, it is a bit super-class, after all, the millimeter level, it is really too difficult to master. So how thin is the thickness of fine sugar?

According to the technical requirements of GB 317-2006 white granulated sugar, white granulated sugar can be divided into four levels: refined, excellent, first and second grade. Different grades of granulated sugar are different in purity and particle size accuracy. The granule value of sugar is also divided into coarse grain (0.800~2.50mm), large grain (0.630~1.60mm), medium grain (0.450~1.25mm) and fine grain (0.280~0.800mm), in which the grain is uniform and the particle size should not be less than 80% in the following range.

Generally speaking, this kind of contrast has to be distinguished by sight and touch, and unless experienced, it is difficult to be precise and unfriendly to rookies. In addition, after the coffee bean has been ground, compared with the sugar crystal, the shape of the coffee powder is irregular. It is more difficult to handle accurately, either visually or tactile.

Why should we pay attention to the degree of grinding?

In order to experience the impact of grinding degree most intuitively, friends can brew the raw coffee beans, the coffee powder with the thickness of granulated sugar and the fine coffee powder like flour at the same water temperature, the same proportion of water powder and the same use, and then taste the coffee extract for comparison.

As far as we generally know, when the substance of coffee beans is certain, the larger the surface area of the extracted substance, the more substances will be released at the same time. The flavor of coffee is not all good, so we need to find a suitable grinding degree to extract the good flavor of coffee.

How to choose the degree of grinding?

If there are a variety of coffee brewing utensils at home, it is not difficult to find that each brewing method has its own corresponding submerged particle size. For example, espresso, which is extremely rich in flavor, is made from a semi-automatic coffee machine, while this espresso uses a coffee particle value of about 0.2mm--0.3mm. And usually we most often see, but also the most often talked about hand-made coffee, its coffee particle value in 0.6mm--0.8mm is the most ideal.

However, the particle sizes mentioned here are all less than 1 mm, so there may be some naive friends who immediately went to find a ruler to measure. The question is, do you have this kind of ruler that can measure 0.1 mm? Even if you do, then, how do you measure it? I can't stop measuring when I see you cross-eyed!

At this time, Qianjie will introduce a tool, which is also a thing that Qianjie often mentions when referring to the degree of grinding-the Chinese standard No. 20 screen (0.85 mm). No matter what the price of the bean grinder, the ground coffee powder is thick and fine, so we want the vast majority of coffee powder to be in the range of 0.6 mm-0.8 mm. Qianjie coffee uses 0.85mm standard sieve pass rate of 80% as the grinding thickness of medium and light roasted coffee beans.

However, in addition to judging the coffee grinding fineness in terms of data, we can also judge whether the coffee grinding degree is appropriate according to the coffee brewing process. Brewing time is a reference, the front street brewing parameters standard, the extraction time of a cup of hand coffee is about 1 minute 50 seconds to 2 minutes 10 seconds. If the grinding degree is too fine, the extraction time will be prolonged; if the grinding degree is too coarse, the extraction time will be shortened.

Or observe the settling speed of the coffee powder layer during brewing, generally speaking, the settling velocity of the powder layer decreases slowly and uniformly, if the falling speed is fast, it may be that the settling speed is too coarse, while the settling speed is getting slower and slower, or even clogged, it may be grinding too fine or too much fine powder, and the bottom of the powder layer appears muddy.

Next, Qianjie takes Shirley from Honduras as an example and chooses two degrees of grinding as a control. First of all, Qianjie routinely introduces this coffee bean.

Shirley, Honduras

Producing area: Masaguara, Honduras

Manor: Moca Manor

Altitude: 1500m--1700m

Variety: Kaddura, Kaduai, Pacas

Treatment: fine washing whisky barrel fermentation

Honduras is located in the north of Central America, facing the Caribbean Sea to the north, the Gulf of Fonseca in the Pacific Ocean to the south, Nicaragua and El Salvador to the east and south, and Guatemala to the west, mostly mountains and plateaus.

In the Moca Coffee Manor, because the planting area belongs to the mountains, people pick coffee beans by hand and then process them carefully in order to produce better coffee beans. Honduras collects 3 million bags of coffee every year and provides you with multi-quality coffee. It has become one of the top ten coffee exporters in the world.

This coffee bean contains three varieties of coffee beans: Kaddura, Kaduai and Pacas.

[Kaddura] Kaddura is a natural variety of bourbon and was discovered in Brazil in 1937. The Kaddura tree is smaller than bourbon. Due to inheriting the bourbon blood, Kaddura is less resistant to disease, but its yield is higher than that of bourbon. Although Kaddura was found in Brazil, this variety is not suitable for growing in Brazil, but is popular in Central and South America, such as Colombia and Costa Rica.

[Kaduai] Kaduai is an artificial hybrid between Kaddura and New World (Mondu Novo). Kaduai has a good ability to resist natural disasters, especially wind and rain. Kaduai trees are lower than those of other coffee varieties, and their fruits are not easy to pick. The fruits of Kaduai varieties are both red and yellow.

[Pacas] Pacas is a natural variety of bourbon, a single single gene mutation. The variety was found in 1949 on a farm of the Pacas family in the Santa Ana region of El Salvador. In 1974, the Honduran Coffee Institute introduced this variety and planted it in Honduras.

Qianjie Coffee is a delicately washed whisky Shirley barrel fermentation process used by Honduras Shirley. Fine washing whisky Shirley barrel fermentation treatment is that the freshly picked coffee fruits are carefully washed, then put into mature whisky oak barrels to ferment at a low temperature for 30-40 days (about 15-20 ℃), and then dry in the shade.

Okay, let's explore the effect of grinding degree on this sherry coffee.

First of all, we chose two groups of grinding degrees: group A was BG# 8s and group B was BG#3s. Then carry on the cup test process, as well as the concentration test.

The experimental results showed that the concentration of group A was 0.78% and that of group B was 1.17%.

The more substances you extract, the better. Excessive grinding will extract more bitter macromolecules from coffee. The suitable grinding degree can avoid the situation of incomplete flavor and light taste caused by insufficient extraction, and can also reduce the risk of bitter and full-bodied coffee caused by excessive extraction.

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