How important is coffee extraction time? What is the relationship between Italian concentrated grinding and time?

What we often call coffee extraction is the use of water as a carrier to dissolve the flavor substances in coffee powder. You know, this extraction process takes time, and the longer the extraction time, the more substances will be dissolved. However, not all the substances in coffee have to be extracted. So we need an appropriate time to extract them in the right amount. Different coffee production methods and extraction schemes have different time requirements, when we control the extraction time within this required range, there is a high probability of making a cup of coffee with a suitable taste. Compared with other extraction methods, Italian extraction is more stringent on time control.

Under the high water temperature and the high pressure of 9bar, the extraction efficiency of espresso machine is very high, which makes the extraction very sensitive. Even if the extraction time of espresso is only 3 seconds, the taste of espresso will be very different. Therefore, time is very important for Italian extraction! In the age of concentrated extraction or in ounces, whether the extracted coffee is one ounce or two ounces, single or double, whether it is extracted with 9g powder or 18g powder, the extraction time will be controlled in the range of 20s to 30s.

However, with the passage of time, the quality of coffee beans, the degree of roasting and the function of the coffee machine have all changed greatly, so it is difficult for us to apply the previous formula to extract espresso. So what is the main point of espresso extraction now? In fact, I believe everyone in Qianjie already knows very well:

① uses a double powder bowl as the extraction unit of espresso.

② espresso liquid is calculated by weight instead of volume

The extraction ratio of ③ coffee powder to coffee liquid tends to 1:2.

The extraction time of ④ is more within the time range of 25 to 30 seconds.

This is a commonly used and recommended Italian extraction scheme (for deep baking beans) in major coffee shops: use a double powder bowl for extraction, then the powder-to-liquid ratio is at 1:2 and the extraction time is in the range of 25 to 30 seconds. Through this scheme, we can quickly find the right degree of grinding and make a cup of espresso with suitable extraction rate and taste. Of course, for espresso, time is more than just an "auxiliary" parameter for quick grinding. Time can also be a reference for flavor, from which we can roughly determine the flavor trend of a cup of coffee: for example, we extract with 20g deep-baked coffee powder in a powder-to-liquid ratio of 1:2. If the extraction time is less than 25 seconds, then this cup of espresso is prone to underextraction, thin taste, sour taste and other negative situations; if it exceeds this time, it is easy to over-extract and produce a bitter and irritating taste (limited to the current extraction scheme, 20g powder, deep-baked beans).

At the same time, time is also an index to determine whether the extraction is stable or not. For example, when we adjust a cup of espresso with the right flavor, we can observe whether there is a big error in the time in the 2-3 cups of concentrated extraction. If the error is less than one second, then the extraction parameter is relatively stable, because the adjustment is not affected by many other factors (such as insufficient pressure in the soybean warehouse, residual powder in the soybean warehouse, etc.). However, if the error is relatively large, more than 2 seconds, then it shows that the cup flavor suitable concentration in the process of extraction, we need to re-formulate the concentration plan. So, you know how important time is for the extraction of espresso.

But! What we need to know is that the extraction range of 25 to 30 seconds is not absolute. This time range is more aimed at deep-and medium-roasted coffee beans. Because this kind of coffee is not "extraction-resistant", the extraction time does not need to be too long, and the amount of powder is limited to 20g. For some medium-to-shallow roasted coffee which is more "resistant" (difficult to extract), or the extraction with more powder, the extraction time needs to be extended accordingly, so that the substances in the coffee can be extracted properly. Not to mention the addition of pre-soaking, secondary water distribution network concentration and extraction, they will take a little longer.

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Front Street Cafe

No. 10 Baoqian street, Yandun road, Dongshankou, Yuexiu district, Guangzhou, Guangdong province