Detailed explanation of the proportion of gold gouache in hand-brewed coffee? What are the Gold Cup Guidelines?

Qianjie often mentions two terms in various articles on coffee making: "concentration" and "extraction rate." Why? Because they are closely related to the taste of a cup of coffee.

If you are a veteran coffee player, Qianjie believes that you are no stranger to the concept of the "Golden Cup Code". The so-called golden cup criterion means that coffee has the most popular extraction range. When the concentration and extraction rate of a cup of coffee fall within the range of the golden cup criterion, then the cup of coffee will meet the tastes and preferences of most people. As of today, although Golden Cup Extraction is still rarely mentioned, the concept it conveys is still worth understanding. So today, Qianjie will come to share with you what is Golden Cup Extraction ~

What is Golden Cup Extract? In the 1950s, Lockhart, PhD in chemistry at the Massachusetts Institute of Technology, was hired by the National Coffee Association to conduct scientific research on coffee. During the research, he found that the soluble substances in coffee beans were very limited, accounting for only 30% of the weight of the beans. The remaining 70% is insoluble lignofiber, known as coffee grounds.

It was because of this discovery that he decided to study whether the taste of a cup of coffee was related to the extraction rate and concentration. The results proved that this was the case. From 1952 to 1960, Dr. Lockhart conducted a sample survey of people in the United States and finally arrived at the extraction range of the first golden cup, that is, the extraction rate of coffee was between 17.5% and 21.2%, and the concentration was between 1.04% and 1.39%. This is the prototype of the Gold Cup Code obtained by investigating the taste preferences of the American people.

Later, Dr. Lockhart and his team collaborated with the US Army's Central and Western Research Center to jointly study the data and organized experts to conduct a second cup test of the Golden Cup Guidelines. Finally, the optimal extraction range of coffee was obtained: the coffee extraction rate was 18% to 22%, and the concentration was 1.15% to 1.35%. As a result, this range became what we often call the golden cup extraction theory in the future. As long as the extraction rate and concentration of coffee fall within this range, this cup of coffee will meet the taste preferences of most people.

Here, Qianjie needs to be added. The so-called extraction rate refers to the amount of substances that we dissolve from coffee. The higher the extraction rate, the more substances we dissolve from coffee; the lower the extraction rate, the less substances we dissolve from coffee. Concentration refers to the total amount of solid matter in the liquid, that is, how much coffee soluble matter is contained in a cup of coffee. The more the content, the higher the concentration, and the stronger the taste will be, and vice versa.

Back to Gold Cup Extraction! If the extraction rate of a cup of coffee far exceeds the extraction rate range extracted by the golden cup, then it is prone to negative manifestations such as bitterness, impurities, and astringent, which will be called "over-extraction"; if the extraction rate of coffee is lower than this range, then it will easily appear sour, astringent and other negative conditions due to insufficient soluble matters in the coffee. We will call this phenomenon "insufficient extraction." The extraction rate within the scope of the Golden Cup Guidelines can ensure that coffee will not be over-extracted or under-extracted most of the time. Therefore, in order to make coffee as delicious as possible, everyone will control the extraction rate and concentration within the scope of the Golden Cup Guidelines.

But, as Front Street has always shared, we'd better not use the Gold Cup Code as the only criterion for good coffee. Because coffee within the extraction range of the golden cup may not be good, and coffee outside the extraction range may not be bad. The specific needs depend on what we dissolve out! For example, people's word of mouth actually refers to the excessive dissolution of some negative substances that can make coffee bitter, astringent, and miscellaneous, which makes coffee less delicious. The content of these substances in different coffee beans varies, some are more, some are less.

When there are not many negative substances in coffee beans, or if we don't dissolve too much of these negative substances, then even if we increase the extraction rate far beyond the maximum limit of 22% in the Gold Cup Guidelines, the coffee will not be difficult to drink. Because this cup of coffee itself does not contain many negative substances; but if the coffee beans originally contain a lot of negative substances, then even if our extraction rate is controlled within the range of the Golden Cup Guidelines, the coffee will not be much drunk. For example, Qianjie Jade Estate·Green Label Rose Summer in Qianjie Bean List, even though its extraction rate is as high as 23%, it still does not show any negative manifestations such as bitterness, impurities, or astringent. We can still taste the obvious floral, fruity, and sweet taste.

The same goes for concentration! Some friends like to drink stronger coffee, while others like to drink weaker coffee. For example, Italians need coffee with a concentration of more than 10%(espresso). If you rashly take out a cup of hand-brewed coffee with a concentration of only 1.15% and give it to him, the consequences... You can imagine that in short, we don't need to use the Gold Cup Code as the only criterion for good coffee. Its existence is more just to provide coffee lovers with an extraction benchmark to refer to when they first start. Coffee that meets the Golden Cup guidelines may not be good, and coffee that does not meet the requirements may not be bad. The key is to understand the relationship between extraction rate, concentration, and ratio in the guidelines, so that we can easily brew a delicious cup of coffee at any time ~

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