What is the difference between a single flour bowl and a double flour bowl? What does a shot add? What does shot mean? How much is a single espresso?

"add shot" is a coffee enhancement option offered by coffee shops. When we think the coffee is not strong enough, or we want to eat more caffeine, we can add a shot to the coffee we have ordered.

The 1shot in coffee refers to a single espresso, while the word "Shot" is a technical term in the wine field and is a measuring unit. 1shot equals 1 division, and 1 division equals 30ml. In the early days, 1shot referred to a single 30ml espresso extracted from 911 g of coffee powder, but since the concept of extraction has changed, 1shot in most coffee shops now refers to a double espresso extracted with 18 to 20 g of powder. Of course, many coffee shops worry that customers will not be able to accept the concentration of four portions of concentrate, so they will use the original parameters and extract a double espresso and divide it into two parts. One is poured into the guest's coffee, and the other is either discarded or drank on its own, which is a common practice of merchants before boutique coffee is popular. But many friends who have coffee machines at home know that in addition to the double one, there is also a single powder bowl for coffee. This kind of powder bowl is used for early extraction of 911g coffee powder, and they look like ↓.

So here comes the problem. Why would the store prefer to extract two portions of concentrate rather than use a single powder bowl to extract one? Isn't it better to save resources and costs? In fact, the reason is very simple, it is precisely because of the advanced concept of extraction that we have changed the way of extraction, but the single powder bowl can not meet the current extraction, so it has been eliminated. So let's come to Qianjie today to share why a single powder bowl has been "eliminated".

Let's first look at the difference in appearance between a single powder bowl and a double powder bowl:

The overall appearance of our common double powder bowl is a cylinder, and when the extracted pressed powder is knocked out, it will also be a regular round block.

On the other hand, the single powder bowl is somewhat irregular, mainly a double-layer inverted cone structure. The mouth of the upper bowl is the same as that of a regular powder bowl, but since a single serving uses half less powder than a double bowl, the lower layer of the single bowl has a narrowed design to keep the mouth consistent at the same time. the maximum thickness of the powder bed is the same, which gives more room for extraction. But! Extraction is not as simple as you think. The application of a single powder bowl is not just to pour 20g powder in half and then use it, such as the extraction experiment done under the front street. Qianjie uses a two-part powder bowl to extract coffee liquid from 40ml on the basis of 20g powder, which takes 30 seconds, the measured concentration is 11.28%, and the extraction rate is 21.89%. On the other hand, the coffee liquid of 20ml was extracted by using a single powder bowl based on the amount of 10g powder. The flow rate will be a little faster. The key is that there are many spatter effects in the process of extraction, in short, the channel effect.

It took 18 seconds, the concentration was 8.55%, and the extraction rate was 18.12%. It can be seen that the extraction rate is not the slightest bit. If we want to increase the extraction rate and concentration of a single powder bowl to the same data as a double powder bowl, we must add powder or fine-grind so that the hot water has plenty of extraction time. But this will undoubtedly allow businesses to increase more costs, such as the cost of grinding materials, as well as time costs. After several rounds of extraction, Qianjie found that the amount of powder needed to be 13g, and all aspects of concentration (concentration, extraction rate, taste) would be close to the concentrated taste extracted by a double powder bowl. The reason why there is such a big difference is precisely because of the structure of the powder bowl.

As you can see, the structure of the double powder bowl is a straight column, which means that every part of the powder bed can be subjected to uniform force, whether the powder is pressed or extracted under pressure in the coffee machine. Therefore, in the process of extraction, hot water can extract most of the powder bed more evenly.

The single powder bowl is different, it is subject to more restrictions. It is not only necessary to keep the caliber of the upper layer consistent with other powder bowls in order to fit the cooking head, but also to compress the bottom space and change the bottom structure in order to ensure the thickness of the powder layer. Then such a powder bowl with a wide top and a narrow bottom will cause the pressure around the coffee powder to be higher than that in the center of the same level, no matter when the coffee powder is pressed or extracted.

Then, when the hot water is extracted, it will give priority to the central part of the extraction, then it will be around, and when the hot water permeates into the lower layer, it will concentrate on the central extraction. This is a completely different extraction state from the conventional powder bowl, and it is very easy to produce uneven extraction and then lead to channel effect. We can fully see this from the pressed powder and the "residue" in the bowl.

Therefore, when the concept of extraction is updated and iterated, the shortcomings of the single powder bowl are completely exposed, and it is unable to keep up with the times, and is gradually eliminated with the passage of time.

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