Why is the coffee made by the coffee machine not strong? why does espresso have to be debugged every day?

"Why do you have to debug the extraction parameters of espresso every day? Are all the same batch of coffee beans, the same machine, the same extraction scheme, is there any other change? " There is! Maybe I don't feel it for a day or two, but by the time I find it, I don't know how many guests have drunk bad coffee.

Don't think the coffee machine & bean grinder has not changed!

From everyone's point of view, these machines are very fixed things, as long as pay attention to daily cleaning and maintenance, there will be few problems ~ when the machine is still very new, of course! But coffee machine brewing pipes, brewing heads, steam boilers, pressure valves, pressure relief valves and so on are in operation every day, there will be varying degrees of wear and tear (too small to detect), and then suddenly one day can not hold on to collapse! There are often signs before the collapse of these parts, such as abnormal water output during brewing, insufficient effluent temperature, insufficient extraction pressure, etc., which are obviously reflected in the taste of extracted espresso, such as uneven extraction, insufficient extraction and so on.

Or the Italian coffee grinder, the knife head of the grinder is grinding day after day, it is also a situation that will continue to wear out, and then the coffee particles may become thicker and thicker at the same scale, or there may be more fine powder. These conditions can also be reflected in the taste of extracted espresso, such as acidity, bitterness, bitterness and so on.

Even for the same batch of coffee beans, with the increase of storage days

The state of coffee beans also changes every day!

All coffee beans sold on Qianjie Street will be shipped within five days after roasting. A large amount of carbon dioxide will be produced in the coffee beans during the roasting process, which will continue to release itself in the days after roasting. And what we call the taste period is actually the effective exhaust period of coffee beans. These carbon dioxide can achieve the role of keeping fresh / retaining flavor, but with the increase of storage days, the release of carbon dioxide will also take away some of the coffee flavor, until released, the coffee beans will lose freshness and flavor. In other words, the flavor of coffee beans changes all the time, especially after one night, the change of flavor state is more obvious.

The front street espresso beans are roasted at medium depth, so there is more carbon dioxide in coffee beans than light / medium roasted beans, and this carbon dioxide affects the performance of espresso during extraction. The fresh espresso beans have more carbon dioxide, which will slow down the flow of water during extraction and prolong the extraction time. In the end, espresso will show a very rich oil affecting the overall taste, and in serious cases, excessive extraction will occur. When the coffee beans emit about the same amount of carbon dioxide, more than half of the flavor is gone (it starts to be stale), and the flow of water naturally speeds up, shortening the extraction time. Eventually the espresso will show a thin coffee fat and taste will become thin and boring.

How to adjust the extraction parameters of espresso every day?

The extraction parameters of the previous day were used for the first espresso extraction every day. As each blend of coffee beans has different extraction parameters, Qianjie takes the warm sun blend coffee beans extraction parameters used by stores as an example. Warm Sun blend Coffee beans are made from Honduran Shirley and Yega Sheffield sun-red cherries with flavors of chocolate, berries, cream, vanilla and wine. (do not change the extraction parameters of the grinding scale / coffee machine at will for each day, unless you can no longer adjust the coffee flavor performance by increasing or decreasing the amount of coffee powder extracted and the extraction ratio. )

Qianjie yesterday's espresso extraction parameters are 20g coffee powder extraction 40g coffee liquid, extraction time is 28-29 seconds. Today, after adding coffee beans to the coffee store, the same parameters are used to extract the espresso. The espresso has a heavy taste of black cocoa, thick oil, lack of wine aroma and soft acidity. Then extract with the same extraction scheme, confirm whether it is consistent, and eliminate the problems of artificial operation (such as uneven distribution of powder, imbalance of pressing powder, etc.).

Make sure that the non-artificial operation appears and then adjust it. The rich situation may be due to the coffee barn replenished with beans, with more gravity pressing the knife head during the grinding process, coffee beans will be cut more evenly, and the particles will be more uniform and delicate. In view of this situation, Qianjie decided to reduce 0.3g powder today and extract 40g coffee liquid with 19.7g powder for 26-27 seconds. After adjusting the parameters, this time the oil is very rich, you can feel the wine aroma of sherry coffee beans, the soft berry acidity of red cherry coffee beans, the overall smoothness of vanilla cream, and the finish of nut chocolate.