Italian Coffee | How to judge the quality of espresso to adjust the grind size?

Espresso has very high requirements on the grinder. A good grinder can solve many problems in making espresso. In order to ensure that the taste of espresso remains consistent, our baristas will adjust the grinder every day. Today, we will take a single serving of espresso as an example to adjust the grinder.

In addition, when making espresso, there are at least three main parameters to measure: powder dosage, extraction volume and extraction time.

After the coffee machine is preheated, you can adjust the grind. The specific steps are as follows:

1. Before pouring the beans into the bean hopper, blend the coffee first, select the defective beans, and then pour them into the bean hopper; and open the valve between the bean hopper and the grinder to allow the coffee beans to fall smoothly into the grinding area.

2. Turn on the grinder for 10 seconds, adjust the grinding degree and discard the coffee powder.

3. We can first extract the coffee according to yesterday’s extraction parameters, and think about how to adjust the grinder by judging the quality of the espresso.

Single shot espresso extraction:

Use 12-14g of powder in a 1:1.5 ratio to extract 20g, and the normal time is within 25-28 seconds; if the powder is too coarse, the water will flow through the powder bowl too quickly, the water flow will be coarse, the extraction will be shallow, the color will be white, and the flavor will be sharp and sour, because the extraction is incomplete, only the surface and easily extracted acidic substances are extracted.

4. Judging the quality of espresso:

① Concentrates that are lighter in color and thin in oil can basically be judged as insufficiently extracted.

② If the color is very dark and the color of the surface oil is inconsistent, it can be judged as over-extraction.

③ The appearance of spots of grease on the surface can be judged as perforation resulting in partial over-extraction.

Single head adjustment steps:

(1) First grinding, single head 14g, grinding degree #2.2, extraction 21g, time 24 seconds

Taste: Fast flow rate, sour aroma, obvious acridity in the mouth, uncomfortable taste, thin texture, less bitter taste, white oil on the surface, mixed taste;

Speculated reasons:

If the powder is too coarse, the water will flow through the powder bowl too quickly, resulting in coarse water flow, shallow extraction, white color, and a sharp and sour flavor. It is also possible that the powder layer is partially perforated, resulting in incomplete extraction, and only the surface and easily extracted acidic substances are extracted, which is insufficient extraction.

Adjustment method: At this time, you need to fine-tune the grinding disc scale to 0.2 grids, and then conduct the test.

(2) Second grinding, single head 14g, grinding degree #2.1, extraction 21g, time 28 seconds

Taste: The sour taste is softer and sweeter than the first time, the texture is thicker than the first time, the mouthfeel is comfortable, there is honey sweetness in the middle, very little bitterness, the surface is rich in fat, and there is a lingering taste of dark chocolate and nuts;

Speculated reasons:

The grinding degree is moderate, which can extract sour and sweet substances in a more balanced manner, and the oil can be extracted.

In addition, if you still cannot achieve the ideal taste of espresso after adjusting the grinding size, you can adjust it through the extraction time.

If the espresso extraction time is too long today, and it takes more than 30 seconds to reach the coffee extraction amount you set, it will basically taste bitter and have a very unpleasant coffee flavor. At this time, you need to find a way to shorten the time so that the coffee can stop being extracted in the ideal coffee flavor.

Suppose if you feel that the espresso is too sour after extracting it for 15 seconds, you can extract it for 20 seconds. If you feel that it is still too sour after 20 seconds, you can extract it for 25 seconds.

Suppose if you find the espresso too bitter after extracting it for 30 seconds, you can extract it to 25 seconds. If you still find it a little bitter after 25 seconds, then extract it to 20 seconds.

It’s actually very simple, isn’t it? ! That’s all for today. Have you learned something new?

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