Basic knowledge of barista basic knowledge of hand-brewing coffee brewing skills coffee bean grindability water temperature ratio parameters

[dissolution] and [diffusion] are the principles of hand-brewed coffee

So what does dissolution and diffusion mean?

[dissolution] refers to the chemical reaction of coffee beans after roasting to produce coffee ingredients that give off the aroma and taste of coffee, with a variety of chemical macromolecules and small chemical molecules, which are the aroma, sweetness, sour taste, bitterness and so on. In order to extract these coffee ingredients, you need to grind the coffee into powder, then slowly inject water to dissolve the ingredients in the coffee.

[diffusion] means that in daily life, we know that in order to dissolve better, we need to grind the powder more finely, but in hand-brewing coffee, if we grind the coffee powder very fine, it will block the filter paper. So you have to grind the coffee powder to the size of fine granulated sugar (medium to fine grinding), but in this way it will dissolve unevenly (coffee substances have small molecules that are easy to dissolve and macromolecules that are not easy to dissolve). It needs the help of "steaming", "stirring" and "shaking the sharing pot" in the extraction (there will be a concentration difference in the process of dissolving by water injection. Shake the sharing pot after extraction It's for uniform coffee concentration.

What is the flavor of a cup of hand-made coffee in the process of extraction?

You can interpret it this way and divide it into three paragraphs:

The first stage is the aromatic substances and acids that are easily extracted (floral and fruity).

The second paragraph is the sweetness and caramelization of coffee.

The third paragraph is the bitter and astringent taste of coffee, and all we have to do is to extract the flavor of coffee with water.

There are also three cases in the process of extraction: gold cup extraction, insufficient extraction and excessive extraction.

Gold cup extraction

If you play with coffee, you have to mention the Golden Cup Theory. Many friends who play hand Chong know that the extraction rate of the gold cup is 18% Mur22%, but what kind of data is it? A lot of people don't quite understand.

The Golden Cup Theory (Gold Cup) holds that "good coffee" must conform to both.

1. The extraction rate is between 18% and 22%.

two。 The coffee concentration is in the range of 1.2% to 1.45%.

Gold cup extraction is considered to fall within the ideal extraction range when the concentration of your brewed coffee is between TDS 1.2 and 1.4, and the extraction rate is also up to 18%-22%. What has not yet reached this extraction range is what we call insufficient extraction, while exceeding it means excessive extraction.

Coffee extraction rate: indicates that the weight loss of coffee beans in the brewing process accounts for the proportion of coffee beans used.

Coffee concentration: the proportion of the extracted coffee substance to the total coffee liquid.

Insufficient extraction

Insufficient extraction means that there are not enough substances brought out in the extraction process, and there are still extractable substances in the coffee powder. The coffee is tasted with acidity, sweetness, salty feeling, thin taste and short aftertaste.

Excessive extraction

"excessive extraction" means that coffee powder has been in contact with water for too long, extracting too many substances that we do not want, and coffee has an obvious bitter, mixed and astringent taste.