What is Italian concentration? How to judge the quality of a cup of espresso?

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In addition to the most important taste, oil is probably the most commonly used criterion for judging the quality of espresso. Its color, evenness, thickness and fineness directly tell us the quality of a cup of espresso.

We should judge the quality of a cup of espresso from the following aspects:

[flow rate determination]

The flow rate of Italian coffee directly determines the taste of ESPRESSO, too fast flow rate will make the essence of coffee has not been dissolved into the water, but the water has passed through the coffee powder, resulting in coffee tasteless; too slow flow rate will make the essence and dross of coffee all into the water, resulting in coffee with obvious scorching taste or exciting bitter taste.

How to judge the quality of a cup of espresso (espresso) for beginners, the flow rate control is a quantitative standard, generally we take 22 seconds to 28 seconds as the best value. The more advanced ones will judge the flow rate by the shape of the water flow when the coffee is extracted. Foreign baristas like to use the mouse tail to describe the flow rate of coffee.

The higher level is that the flow rate of coffee is determined by its taste. If the flow rate is faster, the taste will be single but refreshing, and the sour taste will be heavier; if the flow rate is slow, it will increase the mellowness, and the more complex but bad taste will be released at the same time. The bitterness will be a little heavier. The speed of the flow rate is a dynamic process, no barista or any kind of coffee equipment can guarantee the consistency of the coffee flow rate, and even the humidity of the weather will affect the speed of the coffee flow. So baristas must know that it is easy to control the flow rate rather than being controlled by it.

[thickness determination]

The thickness of ESPRESSO grease is a very complicated problem, which is much more complicated than the color of grease. The thickness of the grease is essential for making a real cappuccino and the popular coffee flower, so the rich and long-lasting grease can be said to be an important sign of high-quality ESPRESSO.

The grease of ESPRESSO is not really a layer of "oil" floating on the surface of coffee, but is composed of delicate bubbles, so when we study the thickness of grease, we should not only look at how thick it is, but also observe how long it can last. The thickness of oil generally has a lot to do with the freshness of beans. If the beans are too fresh, the extracted oil will be very thick, but it will dissipate very quickly. We think that this kind of oil is too rough. Therefore, bean cultivation plays an irreplaceable role in the formation of oil. Only beans raised correctly can extract long-lasting oil. Although the fat is too thick is not necessarily a good thing, but if the oil is too thin, it must be a bad thing, generally due to: beans stored for too long or improper preservation; too little powder; grinding too coarse or too fine; extraction time is too long or too short; the flow rate is too large; improper filling pressure and other reasons. Generally speaking, I personally think that a serving (1 ounce) of ESPRESSO is a sign of high quality oil with a duration of at least 2 minutes.

[color determination]

The color of Italian coffee oil can well reflect whether the extraction degree of ESPRESSO is moderate, whether the powder is enough, whether the filling force is in place, whether the water temperature of the coffee machine is correct and whether the beans are fresh and many other factors.

The color of Italian coffee oil is preferably golden yellow and slightly brown, and the color of oil is milky white, which is generally called underextraction, while the preference for dark brown is excessive extraction.