Boutique Coffee Science talk about Espresso Gold Rule

Espresso has always had a very high status in the hearts of coffee lovers, not only because of its rich taste and pure Italian origin, but also because Espresso is not only a test of skill for coffee players, but also a knowledge and love of coffee.

Hydraulic pressure

The modern coffee machine is much more advanced than the old LAVA machine, which is controlled by a water pump to output controllable water pressure. Espresso ideal water pressure is generally 9 BAR, which is generally recognized as the most ideal atmospheric pressure.

Boiler pressure

The boiler pressure is related to the water temperature of coffee making and the impulse of steam. The higher the boiler pressure, the higher the water temperature and the greater the impulse of the steam; otherwise, the lower the water temperature, the smaller the steam. The boiler pressure is generally around 1 BAR, but there is still a lot of controversy about this number, and every barista has a different understanding.

Water temperature

The water temperature depends on the needs of different varieties of coffee beans, some are subject to boiler pressure, while others are more flexible and precise. According to the experience of most baristas, the water temperature is between 90 and 92 degrees Celsius, and each barista can flexibly adjust according to his own understanding and needs, which is why the editor has always envied professional baristas and can make their own style Espresso with their own hands.

Filling force

There are various styles of packing. In this world, almost no two people's packing will be the same. Generally speaking, if it is heavy pressure, the required pressure will be the pressure like 25kg/m2, but packing is indeed the freest parameter in the golden rule.

Coffee bean grinding thickness

The grinding thickness will be related to many factors, such as climate, coffee bean baking degree, freshness, humidity, new and old bean grinder, and so on. There has always been a saying in the industry: "the right thing is that the grinding thickness is changing, and the wrong thing is that the grinding remains the same."

Powder quantity

The amount of Espresso powder in a single serving is 7-8 grams of coffee powder, and the double serving is 15-16 grams, which is a good math problem.

Extraction time

The extraction time of the Espresso gold rule is between 22 and 28 seconds, but the extraction time is actually a combination of packing pressure, powder content and grinding degree, which needs to be adjusted by the barista's understanding of Espresso.

Extraction quantity

Almost no one will change the amount of Espresso 30ml per serving and 60ml double, except for a few Italians who use a single serving of coffee powder to extract only 15ml of coffee liquid.

Coffee oil

The complexity of coffee grease can not be clearly explained by me in a few words. To put it simply, it requires a rich golden brown fat to make a good Espresso.