In addition to the taste, crema is probably the most commonly used criterion to tell the quality of a cup of espresso, including its color, evenness, thickness and fineness.
We should judge the quality of an espresso from the following aspects:
Flow rate
The flow rate of coffee directly determines the taste of ESPRESSO. If it is too fast, the essence of the coffee has not yet dissolved into the water, but the water has already passed through the coffee powder, resulting in the coffee being bland; if it is too slow, the essence and dregs of the coffee will all be integrated into the water, resulting in the coffee having a distinct burnt taste or irritating bitter taste.
How to judge the quality of a cup of espresso, for beginners, the control of flow rate is a quantitative standard, generally 22 seconds to 28 seconds for an optimal value. The more advanced will judge the flow rate by the shape of the water when the coffee is extracted, and some like to use the mouse tail to describe the flow rate of coffee.
The higher level is based on the taste to determine the flow rate of coffee, the flow rate is fast, the taste is single but more refreshing, and the sour taste will be heavier; The slower flow rate will improve the alcohol, the taste is more complex but at the same time the bad flavor will be released, and the bitterness will be heavier. The speed of the flow rate is a dynamic process, no barista or coffee equipment can ensure the consistency of the coffee flow rate, and even the weather humidity will affect the speed of the flow rate, so the barista must know how to easily control the flow rate rather than being controlled by the flow rate.
Thickness
The thickness of the crema is crucial to making a real cappuccino and the popular latte coffee, so a rich, long-lasting crema can be an important sign of a good ESPRESSO.
The crema is composed of delicate bubbles, so when we study the thickness of the crema, we can not just look at how thick, but also observe how long it can be maintained, both of which are equal.The thickness of the crema is generally closely related to the freshness of the beans. If the beans are too fresh, the crema extracted will be very thick, but it will also dissipate quickly. We believe that such crema is too rough.
Color
The color of the coffee crema can well reflect whether the extraction degree of the ESPRESSO is moderate, whether the amount of 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 best color for ESPRESSO coffee crema is golden yellow with a slight brown tint. If the color of the crema is milky white, we generally call it under-extraction, and if it is dark brown, it is over-extraction.
Key words: What is ESPRESSO; the crema of espresso