Coffee extraction Theory-Golden Cup Criterion Professional Coffee knowledge

The taste and extraction methods of coffee are very diverse. The European Fine Coffee Association has put forward the concept of "Gold cup", that is, the "golden cup criterion". A certain extraction rate and coffee concentration determine the taste of coffee, but what is the extraction rate, and what is its effect on the taste of coffee? Let's do some knowledge sharing.

What is the Golden Cup Criterion (Gold Cup Standard)

The SCAA gold cup standard is: the best extraction range of coffee is 18%-22%, and the best concentration range is 1.15%-1.35% (i.e. 11500ppm~13500ppm). Some people don't like it, because even the coffee made according to this is not necessarily good, so they scoff. To understand it this way: coffee that is not in line with the golden cup theory is good, but the golden cup theory provides an important theoretical basis for our "extraction" this important matter. but it can be said that what does not conform to the golden cup must not taste good. Therefore, the golden cup theory is only a reference, is dead, while people are the main body, is alive, do not let the golden cup become the shackles of coffee.

Extraction rate: the ground coffee powder is not completely soluble in water, and the compounds that can really dissolve in water account for about 30%. In general coffee cooking, about 18% 22% of the substances in coffee powder dissolve into water, while that of Espresso is about 15%, 25%, which is called extraction rate. If the extraction rate in a cup of coffee is on the low side, it is called insufficient extraction, while too high extraction rate is over extraction, but it is very important. The extraction rate and coffee concentration are completely different.

Coffee concentration: weight of all compounds dissolved in water / total weight of coffee solution

When more than 1000 coffee compounds appear in the process, no two cups of coffee will be exactly the same, but how do we know that degree of extraction would be the best? fortunately, these flavors can be classified into several categories. Compounds classified as homogeneous are extracted at similar temperatures and processes, generally with heavier molecules dissolving more slowly, while lighter ones dissolving faster.

Filter coffee tube table (left vertical for coffee liquid concentration, bottom for coffee powder extraction rate%, upper and right vertical for powder / water)

This quality control table is compiled by experts such as Dr. Lockhart with an American trickling filter under the same grinding degree, water volume and water temperature.