The darker the color of crema, the darker the espresso, how to drink the delicious concentrated beans.

Tiger spot

It is generally understood that crema is concentrated with dark brown tiger spots on its surface, which Dr Illy adds to his definition of concentration.

Tiger spots are tiny fragments of coffee powder that are pushed out of coffee pressed powder during extraction. It is usually seen that the tiger spot first appears on the edge of the concentrated cup and gradually distributes to the whole concentrated surface over time. This phenomenon makes the tiger spot not only a sign of a good cup of concentration, but also reflects the performance of the bean grinder to provide the necessary particle distribution for a good cup of concentration.

If the grinding distribution of a bean grinder is too consistent, then, contrary to expectations, these coffee powder particles will not be well mixed. You have to imagine two images, in the same swimming pool, one is full of beach volleyball, and the other is a mixture of beach volleyball, football, tennis (you can also take inspiration from Mark Prince's article on powder pressing and imagine these coffee powder particles into a jigsaw puzzle), different shapes and sizes will make them fit together to form a tight container. The powder particles sometimes overlap with each other or leave a gap for water to pass through at a certain flow rate, and the tiger spot in the cup reflects the grinding distribution of coffee.

By observing Crema, we can judge the freshness of coffee beans, the completeness of coffee extraction and the uniformity of coffee extraction.

How to tell if the coffee beans are fresh: although you can tell that the beans are fresh when you observe a lot of foam, there is also a possibility that Robusta is high. So we can observe the state of foam precipitation instead. If it is very fresh, the whole process of bean extraction will take the form of crema, and when these crema settle down, they will be clearly divided into two layers. If it is a long-term bean, you will see that there is not much concentrated foam coming out of the shunt nozzle during extraction, usually this cup is thin and watery, and the crema will soon dissipate.

How to judge whether the extraction is complete: the darker the color of crema, the more dissolved substances are extracted.

How to judge whether the extraction is uniform: if the crema is stable, the concentrated color is beautiful and the texture is thick, which means that the channels and depressions in the extraction process are less likely to occur.