What can ESPRESSO's CREMA tell us?

There has long been a theory that robusta beans can produce better Crema during extraction. This is true because Robusta coffee beans contain only half the aroma components and aromatic oil content of Arabica coffee beans. This means that less oil is extracted into the coffee, thus reducing the effect of oil on foam stability, so increasing the Robusta coffee beans will reduce the overall amount of oil quenched from the coffee powder, which means that you have a higher chance of making a more stable and richer Crema. Of course, there are a variety of uncertainties that affect Crema. In general, it is how coffee preserves the foam of carbon dioxide, how many kinds and how many oils there are in coffee, and how they are quenched into the cup.

Crema can tell us:

1. Whether the coffee is fresh.

A large number of robusta beans allow us to see a lot of bubbles, so we can't judge the freshness of coffee by watching the speed at which the bubbles disappear. Fresh coffee will have a lot of Crema during the whole brewing process, that is, when the coffee comes out, it looks like Coke. Only when the extraction is nearing the end and a large amount of water appears, will it stop, so that two very obvious stages of the process can be clearly observed. Stale coffee beans often see a thin, separate Crema, and the resulting coffee is often thin and watery, meaning less Crema and faster disappearance.

2. The degree of coffee extraction

The deeper the Crema, the more dissolved matter gets into the cup. (contains over-extracted coffee impurities)

3. The uniformity of coffee extraction.

The more stable the Crema, the better and stronger the coffee we make, and it means that there are fewer gaps in the coffee powder (channel effect) and fewer mistakes in the production process.

What Crema can't tell us:

1. Is the coffee good?

As long as enough fresh, no matter how bad beans, no matter how bad baking can produce rich Crema.

2. The oil in the coffee is properly emulsified

For a long time, many people, including I thought, Crema told us the degree to which the oil in coffee is quenched, that is, the more Crema, the more oil in coffee. But the theory tells us that the more oil there is, the less bubbles it contains. If you try making espresso with 5-6bar pressure, you will find that you can still make a lot of Crema (fresh coffee beans are easy to repeat this experiment), but the coffee tastes very insipid because of lack of oil and aroma. Espresso and Crema are often complicated in coffee making, far more than needed. In the whole production process of Espresso, Crema is a very simple link. There are three main elements in Espresso, one is water, the second is oil, and the third is foam. The body of Espresso is gelatinous, and the oil in coffee is emulsified by hot water at high temperature and high pressure to form a colloid, which is extremely stable. The foam on the surface of Espresso disappears very quickly compared to the colloid. After eliminating the mysterious aura shrouded in Crema, Crema is still a great pleasure of Espresso. Its honeycomb structure stores a lot of aromatic substances, releases a large amount of fragrance when the structure disintegrates, and brings enjoyment to our vision and smell at the same time.