Does Pour-Over Coffee Brewing Require Formulas? How to Calculate Extraction Rate in Coffee Gold Cup Theory
In the past, whether coffee was brewed well depended mainly on experience. Learning to brew coffee often required accumulating considerable experience before gaining insight. However, with the gradual refinement of coffee extraction theories, coffee brewing has slowly evolved from a mystical art to a science.
Understanding coffee extraction begins with the Golden Cup extraction standards. Of course, looking at it now, version 1.0 has become somewhat incompatible with current practices, and the SCA is researching version 2.0. Before version 2.0 is released, FrontStreet Coffee would like to share knowledge about the Golden Cup extraction version 1.0 with everyone.
The Birth of the Golden Cup Standards
In the 1950s, the National Coffee Association (NCA) of the United States hired MIT chemistry博士 Dr. Lockhart to conduct scientific research on coffee. Dr. Lockhart discovered that the substances that could be extracted from coffee beans account for 30% of the bean's weight, while the remaining 70% consists of insoluble solid fibers. He also determined that whether a cup of coffee tastes delicious depends on two factors: coffee extraction rate and coffee concentration (TDS).
Between 1952 and 1960, Dr. Lockhart conducted sample surveys among the American population and found that American preferences for coffee ranged from an extraction rate of 17.5%-21.2% and a concentration of 1.04%-1.39%. This became the prototype of the American Golden Cup Standards.
Subsequently, Dr. Lockhart's team collaborated with the US Army Midwest Research Center to study data and conduct expert cupping, concluding that the optimal extraction range for coffee is 18%-22% with a concentration of 1.15%-1.35%. This became the Golden Cup extraction theory for the Specialty Coffee Association of America (SCAA) and later the merged SCA.
Of course, looking at it now, even if one of the extraction rate or concentration falls outside the Golden Cup range, there's still the possibility of brewing delicious coffee. Therefore, discussing the Golden Cup range doesn't hold much significance today. However, the calculation formulas for extraction rate and concentration that it left behind are still applicable.
How to Calculate Coffee Extraction Rate?
The coffee extraction rate refers to how much coffee substance is released from coffee beans (grounds) after brewing. With this understanding, we can use traditional methods to simply calculate the coffee extraction rate (though it is somewhat time-consuming)!
Since we know that coffee grounds dissolve coffee substances when they encounter water, and the weight of dissolved substances equals the weight lost by the coffee beans (grounds), we simply need to dry the brewed coffee grounds and weigh them. The difference in weight from the original coffee beans (grounds) represents the weight of extracted coffee substances. Therefore:
Weight of extracted coffee substances ÷ Original coffee bean (ground) weight = Extraction rate
For example: If you use 15 grams of coffee grounds for brewing, then completely dry the coffee grounds and weigh them to be 12.3 grams, then the weight of substances dissolved in water is 2.7 grams. The extraction rate of this coffee would be 2.7÷15=0.18 (18%).
However, the drawbacks of this method are quite obvious. First, it takes a long time. Second, the data accuracy is low, particularly due to losses during the drying process of coffee grounds and the precision of weight measurements. Most common electronic scales can only measure to 0.1 gram precision, and a 0.1 gram error can result in a 0.7% error in extraction rate.
Therefore, the extraction rate calculation method we commonly use today is related to coffee concentration. Of course, using this method first requires a concentration detection instrument (TDS meter)!
Understanding Concentration and Extraction Rate
First, let's understand what concentration and extraction rate respectively represent:
[Concentration] represents the proportion of "extracted coffee substances" to the total coffee liquid in a cup.
[Extraction Rate] represents the proportion of "extracted coffee substances" to the total coffee bean weight.
(One is based on coffee liquid, the other is based on coffee beans or coffee grounds)
Based on these conditions, we can derive:
Coffee liquid concentration = Weight of extracted coffee substances ÷ Coffee liquid weight
Coffee extraction rate = Weight of extracted coffee substances ÷ Coffee bean (ground) weight
Combining these formulas, we can derive the calculation formula for coffee extraction rate:
Coffee extraction rate = Coffee liquid concentration × Coffee liquid weight ÷ Coffee bean (ground) weight
With a concentration meter, we can easily know the concentration of coffee liquid, thus easily calculating the coffee extraction rate. However, it's important to note that for drip coffee, since coffee grounds themselves absorb twice their weight in water:
Coffee liquid weight = Water poured - 2 × Coffee bean (ground) weight
Important Notice :
前街咖啡 FrontStreet Coffee has moved to new addredd:
FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou
Tel:020 38364473
- Prev
What Does SOE Stand For in Coffee? What Are the Key Differences Between Single Origin SOE Coffee Beans and Espresso Blends?
For more professional coffee knowledge and coffee bean information, please follow Coffee Workshop (WeChat public account: cafe_style). Let me first explain the difference between SOE and blended beans: Blended beans refer to coffee beans made by combining different coffee varieties, typically referring to the combination of coffees from different origins, as each coffee bean has its unique characteristics
- Next
Differences Between Light, Medium, and Dark Roast Coffee Beans - Detailed Guide to Specialty Coffee Roasting Levels
Professional coffee knowledge exchange. For more coffee bean information, please follow Coffee Workshop (WeChat official account: cafe_style). A brief discussion on coffee bean roasting levels, what's the difference between dark roast and medium roast? Among the factors affecting the taste of a cup of coffee, green beans account for 60%, roasting accounts for 30%, and extraction accounts for 10%. Good roasting can maximize the unique characteristics of green beans while minimizing
Related
- How to make bubble ice American so that it will not spill over? Share 5 tips for making bubbly coffee! How to make cold extract sparkling coffee? Do I have to add espresso to bubbly coffee?
- Can a mocha pot make lattes? How to mix the ratio of milk and coffee in a mocha pot? How to make Australian white coffee in a mocha pot? How to make mocha pot milk coffee the strongest?
- How long is the best time to brew hand-brewed coffee? What should I do after 2 minutes of making coffee by hand and not filtering it? How long is it normal to brew coffee by hand?
- 30 years ago, public toilets were renovated into coffee shops?! Multiple responses: The store will not open
- Well-known tea brands have been exposed to the closure of many stores?!
- Cold Brew, Iced Drip, Iced Americano, Iced Japanese Coffee: Do You Really Understand the Difference?
- Differences Between Cold Drip and Cold Brew Coffee: Cold Drip vs Americano, and Iced Coffee Varieties Introduction
- Cold Brew Coffee Preparation Methods, Extraction Ratios, Flavor Characteristics, and Coffee Bean Recommendations
- The Unique Characteristics of Cold Brew Coffee Flavor Is Cold Brew Better Than Hot Coffee What Are the Differences
- The Difference Between Cold Drip and Cold Brew Coffee Is Cold Drip True Black Coffee