Coffee is really a skill, Ernest Ellar Lockhart, a doctor of biochemistry from the Massachusetts Institute of Technology, proposed the golden cup theory in the 50s and 60s of the 20th century. He analyzed the structure and composition of cooked coffee beans and found that whether a cup of black coffee tastes good depends on how many flavor substances are dissolved, that is, the concentration, also known as the total amount of dissolved solids, and the coffee concentration preferred by Americans at that time was between 115%-1.35%。The concentration of how many flavors of coffee powder are extracted by water and dissolved is related to the concentration, and the ratio of the weight of flavors extracted by coffee powder to the weight of coffee powder before extraction is called the extraction rate.
Dr. Lockhart found that the flavor that can be extracted from cooked beans accounts for about 30% of the weight of cooked beans, and the remaining 70% is insoluble fiber, but 30% of the soluble flavors do not need to be extracted to avoid excessive extraction to produce bitterness, and the extraction rate of 18%-22% can extract all the pleasant flavors, and leave other unpleasant ingredients in the coffee grounds.
Dr. Lockhart combined scientific data with a questionnaire of the public to determine that "the concentration of coffee liquid is between 1."15% to 135% and the extraction rate of coffee powder is between 18%-22%" is the ideal range of the golden cup, only if these two conditions are met can a cup of delicious coffee with a balance of sweet and sour and bitter and strong and palatable, this is the golden cup theory. The concentration is related to the strength of the coffee, and the extraction rate is related to the taste and taste of sourness, sweetness, bitterness and astringency.
In reality, due to differences in food culture, there is still no consensus on the palatable coffee concentration in various countries, but the acceptance of the extraction rate of 18%-22% is generally high, which has been regarded as the guideline and has been used to this day, and the ideal concentration and extraction rate of the Jinbei theory have become the compulsory extraction credits for baristas.
The powder-to-water ratio is directly proportional to the concentration, which means that the higher the powder-water ratio, the higher the concentration, and the lower the powder-water ratio, the lower the concentration. For example, using 300 grams of water (1:15 ratio of powder-to-water ratio) for 20 grams of ground coffee will be less concentrated than 20 grams of ground coffee mixed with 200 grams of water (1:10 ratio of powder-to-water ratio).
1. European Specialty Coffee Association Ideal Concentration 12%-1.45% is about 12-14 per liter of black coffee5 grams of coffee flavor.
2. The American Specialty Coffee Association and the European Specialty Coffee Association merged into the Specialty Coffee Association, and the ideal concentration range was expanded by 115%-1.45% is about 11. per liter of black coffee5-14.5 grams of coffee flavor.
3. The ideal concentration of the Norwegian Coffee Association is 13%-1.55% is about 13-15 per liter of black coffee5 grams of coffee flavor.
Although the ideal extraction rate of the Golden Cup Theory is 18%-22% in the global standard, however, there is still no consensus on the palatable coffee concentration range of the European and American Coffee Association, and for decades, the American Specialty Coffee Association, the European Specialty Coffee Association (SCAE), the Specialty Coffee Association (SCA, in 2017 merged with the European Specialty Coffee Association to form the Specialty Coffee Association), and the Norwegian Coffee Association (NCA) "each blew its own trumpet" , the order of ideal strength of coffee in each association is: NCA> SCAE > SCA.
In 2019, the Specialty Coffee Association published a revised Coffee Brewing Control Table, which expanded the ideal concentration range to 115%-1.45%, which is between the original American Specialty Coffee Association's minimum standard concentration of 115% with the highest standard strength of the European Specialty Coffee Association45%, but the ideal extraction rate range is still stuck at 18%-22%.