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What is the Best Pour-Over Coffee Powder-to-Water Ratio? How Much Water is Needed for 20g of Coffee Grounds?

Published: 2026-01-27 Author: FrontStreet Coffee

Last Updated: 2026/01/27, Often, when we brew coffee, we rely on the Gold Cup Theory, which, under specific conditions, helps us understand the relationship between powder-to-water ratio, concentration, and extraction rate. This allows us to determine the optimal powder-to-water ratio for brewing coffee. Powder-to-Water Ratio What is the appropriate pour-over powder-to-water ratio? 1:15 is likely the most commonly heard answer. The 1:15 powder-to-water ratio seems to exist as an undeniable truth. FrontStreet Coffee often uses this ratio in many pour-over brewing methods.

When brewing coffee, we often rely on the Golden Cup theory, which helps us understand the relationship between coffee-to-water ratio, concentration, and extraction rate under specific conditions. This allows us to determine the appropriate coffee-to-water ratio needed for brewing.

Coffee-to-Water Ratio

What is the appropriate pour-over coffee-to-water ratio? The answer 1:15 is probably the most commonly heard. The 1:15 coffee-to-water ratio seems to exist as an absolute "truth." In many of FrontStreet Coffee's pour-over brewing experiments, when using a 1:15 coffee-to-water ratio, the concentration mostly falls between 1.30-1.36%, with calculated coffee extraction rates between 17.86-18.69%. Through tasting, this ratio also expresses the coffee's flavors very well.

In other words, is the 1:15 pour-over coffee-to-water ratio the golden rule?

FrontStreet Coffee approached this with bold assumptions but careful verification. While using the 1:15 ratio to brew coffee yields excellent flavor performance, could there potentially be an even more suitable coffee-to-water ratio?

In the Golden Cup theory, a concentration of 1.30-1.36% is considered relatively high, while the extraction rate is relatively low—what's known as "high concentration, low extraction." So, if we use more water for brewing, could this reduce the coffee's concentration while increasing its extraction rate?

To verify this hypothesis, FrontStreet Coffee brewed 5 groups of coffee using a 1:16 coffee-to-water ratio. The measured concentration values were between 1.23-1.33%, with calculated coffee extraction rates of 18.18-19.68%. On paper, these data points align perfectly with the Golden Cup range. Through tasting, most coffees showed very suitable overall sensory performance, but one group of Sherry coffee beans exhibited a watery texture with thin flavors, despite measuring a concentration of 1.25%.

The Impact of Coffee-to-Water Ratio on Coffee Flavor

To understand how coffee-to-water ratio affects coffee flavor, FrontStreet Coffee conducted a comparative experiment using Guji 5.0 coffee beans with varying ratios. They tested 1:15, 1:16, 1:17, and 1:18 ratios, measuring concentration and extraction rates while gathering flavor feedback.

"1:15" - Concentration: 1.39%, Extraction rate: 19.11%;
Flavor: Rich, berry notes, enticing aroma.

"1:16" - Concentration: 1.33%; Extraction rate: 19.68%;
Flavor: Berry notes, prominent and pleasant acidity.

"1:17" - Concentration: 1.25%; Extraction rate: 19.80%;
Flavor: Appropriate concentration, acidity weaker than the previous cup, with sweetness emerging.

"1:18" - Concentration: 1.18%; Extraction rate: 19.92%;
Flavor: Acidity weaker than the previous cup, berry notes, aftertaste with bitterness.

In this experiment, each cup had 25ml more water poured than the previous one, revealing that as the pouring progresses, extraction efficiency decreases. This explains why some brewing descriptions mention that early to mid-stage pouring extracts flavors, while later stages adjust concentration.

With the Guji coffee beans, although the 1:15, 1:16, and 1:17 ratios showed slightly different levels of sweetness and acidity, they all presented positive sensory experiences—essentially, different perspectives on deliciousness. The difference between the "1:17" and "1:18" ratios was minimal, and both had concentration and extraction rates within the Golden Cup range. However, human perception detected uncomfortable bitterness in the finish of the "1:18" ratio. We can boldly infer that the final 25ml of water in the "1:18" ratio extracted bitter compounds that reached the human sensory threshold, making the bitterness detectable.

Of course, we also concluded that the Guji 5.0 coffee beans not only perform satisfactorily at a 1:15 coffee-to-water ratio but also show good performance at 1:16 and 1:17 ratios.