Introduction:The flavor profile of pour over coffee largely depends on the brew ratio (coffee to water). This article provides an in-depth yet easy-to-understand analysis of the core principles behind the SCA Golden Cup extraction theory, breaks down how different brew ratios affect taste profiles, and through a real-world test using a Costa Rican Geisha blend, helps you master the calculation of concentration and extraction yield—so you can find the brewing parameters that suit your personal taste.
How should the brew ratio for pour over coffee be determined? The commonly recommended 1:15 is not arbitrary but is based on the scientific foundation of the SCA Golden Cup extraction theory. This article will start with the basic concepts of the Golden Cup standard, explain in detail the definitions of extraction yield and concentration, analyze the flavor tendencies associated with different ratios, and use a Costa Rican Geisha blend as an example. By measuring actual concentration and extraction yield, it will help you find the brewing method that best suits you by bridging theory and practice.
When many coffee enthusiasts ask baristas from a certain brand about brewing ratios, the advice they often receive is 1:15. Why is this ratio so widely recommended? Next, we’ll take a closer look at the brew ratio for pour over coffee and explore the rationale behind this setting.
This brand recommends weighing out 15 grams of coffee beans each time and pouring water at a 1:15 ratio. This recommendation is derived from the SCA Golden Cup extraction theory, where different brew ratios lead to distinctly different flavor outcomes. Generally speaking,Bold & intense flavor rangeis 1:10～1:11 (equivalent to the Golden Cup standard of 1:12.5～1:13.5);Medium flavoris 1:12～1:13 (equivalent to the Golden Cup standard of 1:14.5～1:15.5); whileLight & refreshing stylefalls within 1:14～1:16 (equivalent to the Golden Cup standard of 1:16.5～1:18.5). When the ratio of coffee beans to water is between 1:14.5～1:15.5, it’s easiest to achieve the ideal range of a Golden Cup extraction yield of 18%～22% and a concentration of 1.15%～1.35%. This is also why the brand recommends 1:15 as a universal parameter—it suits the characteristics of most coffee beans.
What is the Golden Cup extraction theory? According to the SCAE (Specialty Coffee Association of Europe), the Golden Cup standard refers to brewing with 1000 ml of water and 50–60 grams of coffee grounds at a water temperature of 92°C～96°C. Coffee brewed this way usually falls in the middle of the optimal extraction yield and concentration values—what is known as the “Golden Cup” range.
So, what is extraction yield? About 70% of roasted coffee beans consists of insoluble fiber, and only around 30% of the components can be dissolved by water to form flavor substances. In other words, out of 100 grams of coffee grounds, up to 30 grams are soluble, while the remaining 70 grams are what we commonly know as coffee grounds. The proportion of these soluble substances that is actually extracted into the brewed coffee is what is referred to as the “Golden Cup extraction yield.”
How is concentration measured? First, the concentration meter must be calibrated using pure water to zero it. Then, thoroughly stir the finished pour over coffee, use a pipette to draw an appropriate amount of coffee liquid, and drop it into the concentration meter before pressing the measurement button. Repeat the measurement several times until the reading stabilizes.
How is extraction yield calculated? Each coffee bean has a maximum soluble extract limit of about 30% (with the remaining 70% being non-extractable parts such as lignin), meaning that 10 grams of coffee grounds can yield up to 3 grams of extractables. The ideal state for a cup of coffee is to extract 60%～70% of those 30% soluble substances. If it’s below 60% (i.e., 30% × 0.6 = 18% or lower), it’s considered under-extracted, often resulting in incomplete flavors; if it’s above 70% (i.e., 22% or higher), it may be over-extracted, often leading to bitterness and astringency. Therefore, the optimal extraction yield range for coffee is 18%～22%.
The formula for calculating extraction yield is: Extraction Yield (%) = Weight of Dissolved Extracts (g) / Weight of Coffee Grounds (g). According to the definition of concentration, concentration equals the ratio of extracted mass to coffee liquid volume, while extraction yield is the ratio of extracted mass to coffee grounds weight. Converting the two gives: Extraction Yield = (Concentration × Coffee Liquid Volume) / Coffee Grounds Weight.
Here, it is generally assumed that the water absorption rate of coffee grounds is 1:2, so the coffee liquid volume can be roughly estimated as approximately 225－(15×2) = 195 grams.
Next, we’ll apply the above extraction yield formula along with actual concentration meter readings to brew a Costa Rican Mirasu Estate Geisha blend, and observe how this coffee performs in terms of extraction.
Costa Rican Mirasu Estate Geisha Blend
Region: Tarrazú, Costa Rica
Estate: Mirasu Estate
Altitude: 1700 meters
Processing Method: Raisin Honey Process
Varieties: Geisha, ET47, SL28, MACIO
Brewing parameters used by the brand are as follows:
Water Temperature: 90°C～91°C
Grind Size: BG#6m (similar to granulated sugar)
Brew Ratio: 1:15
The brand employs a three-stage pouring method: the first pour involves 30 grams of water for a 30-second bloom, followed by 95 grams (scale shows approximately 125 grams), poured over about 1 minute; when the water level drops to two-thirds of the coffee bed, the remaining 100 grams (scale shows approximately 225 grams) are poured over about 1 minute and 40 seconds. The total brew time is around 2 minutes, and the brew is complete once dripping finishes and the filter is removed.
This brew measured a concentration of 1.34% for the Geisha blend. According to the formula, the extraction yield is calculated as 1.34 × 195 ÷ 15 ≈ 17.42%. This shows that the coffee’s concentration meets the standard, but the extraction yield is slightly on the low side. We can adjust brewing parameters such as the brew ratio based on these data to optimize overall flavor performance.
In summary, the Golden Cup extraction theory provides a scientific and standardized reference framework for the coffee industry, becoming a widely used extraction guideline globally. The experiments and products of this brand are also based on this, but it is not an absolute standard. Even if a coffee falls within the Golden Cup range, if it doesn’t match your personal taste preference, there’s no need to rigidly adhere to the theory. Ensuring that every coffee enthusiast can enjoy their desired flavor is the ultimate goal of brewing.
The above content is compiled by CoffeeHunters, a coffee news website.
