Why does Front Street Coffee use a 1:15 pour-over ratio?

Front Street Coffee recommends a 1:15 coffee-to-water ratio for pour-over, meaning 15 grams of coffee to 225 grams of water. That figure comes from the SCA Golden Cup extraction theory, which targets an 18% to 22% extraction yield and a 1.15% to 1.35% concentration. Ratios between 1:14.5 and 1:15.5 hit that window most reliably across a wide range of beans.

The range shifts with taste. Bold cups sit around 1:10 to 1:11, moderate ones near 1:12 to 1:13, and light, refreshing brews at 1:14 to 1:16, which map to roughly 1:12.5 to 1:13.5, 1:14.5 to 1:15.5, and 1:16.5 to 1:18.5 under Golden Cup guidance. The Gold Cup standard itself uses 50 to 60 grams of grounds per 1000 ml of water at 92 to 96 degrees Celsius.

How exactly should you decide the coffee-to-water ratio for pour-over coffee? Front Street Coffee has always recommended 1:15, and this is not an arbitrary choice but a scientific calculation based on the SCA Golden Cup extraction theory. This article will start with the Golden Cup standard and the definitions of extraction yield and concentration, gradually explain the ratio ranges for different taste preferences, and use a Costa Rica Geisha blend as an example to actually measure concentration and extraction yield, helping you find the brewing parameters that suit you between theory and practice.

If you have read Front Street's articles, or have personally visited FrontStreet Coffee to ask the baristas about brewing ratios, you will most likely get the same number—a coffee-to-water ratio of 1:15. Why does FrontStreet Coffee always use 1:15 as the recommended value? Next, we will focus on the coffee-to-water ratio for pour-over coffee and discuss the basis for Front Street's setting of this parameter.

FrontStreet Coffee recommends weighing out 15 grams of coffee beans for each brew and pouring water at a ratio of 1:15.

This recommendation comes from the SCA Golden Cup extraction theory. Different coffee-to-water ratios will lead to completely different flavor directions.

【Bold flavor】1:10–1:11, which is 1:12.5–1:13.5 under the Golden Cup guideline

【Moderate flavor】1:12–1:13 (that is, 1:14.5–1:15.5 under the Golden Cup guideline)

【Light and refreshing】1:14–1:16 (that is, 1:16.5–1:18.5 under the Golden Cup guideline)

When the ratio of coffee bean grams to brewing water falls between 1:14.5 and 1:15.5, it is easiest to hit the ideal range of a Golden Cup extraction yield of 18%–22% and a concentration of 1.15%–1.35%. This is precisely why Front Street uses this range as a general recommended parameter—it can suit the vast majority of coffee beans.

What is the Golden Cup extraction theory?

According to SCAE's (Specialty Coffee Association of Europe) definition of the Gold Cup Standard: use 1000 ml of water with 50–60 g of coffee grounds and brew with hot water at 92°C–96°C. The coffee obtained this way will fall into the middle zone between the optimal extraction yield and concentration values, and this middle position is called the Gold Cup.

What is extraction yield?

About 70% of roasted coffee beans is water-insoluble fibrous material, and the flavor substances that can be brought out by water account for only 30% of the roasted bean weight. In other words, in 100 g of coffee grounds, at most only 30 g can be dissolved, and the remaining 70 g is what we know as spent coffee grounds. The proportion of these 30% soluble substances that is actually extracted into the cup is what is called the "Golden Cup extraction yield."

How do you measure the concentration value?

First calibrate the concentration meter and zero it with pure water. Then stir the pour-over coffee that has completed extraction evenly, use a titration tube to take an appropriate amount of coffee liquid, drip it into the concentration meter, and press the measurement button. Repeat the measurement several times until the reading stabilizes.

How do you calculate extraction yield?

The upper limit of extractable substances in each coffee bean is about 30% (the remaining 70% is xylem and other non-extractable parts). That is to say, 10 g of coffee grounds can dissolve at most 3 g of extract. The ideal state for a cup of coffee is to extract 60–70% of this 30% of soluble substances. Below 60% (that is, below 30% × 0.6 = 18%) is underextraction, and the flavor will seem incomplete; above 70% (that is, above 22%) enters overextraction, which easily brings out bitterness and spiciness.

Therefore, the optimal extraction yield range for coffee is 18%–22%.

Extraction yield (%) = weight of extracted dissolved substances (g) / weight of coffee grounds (g)

According to the definition of concentration, concentration equals the ratio of the weight of extracted substances to the amount of coffee liquid; while extraction yield is the ratio of the weight of extracted substances to the weight of coffee beans.

After converting the two formulas, we can get: extraction yield equals concentration multiplied by the weight of coffee liquid, then divided by the weight of coffee beans.

Here it is usually assumed that the water absorption rate of coffee grounds is 1:2, so the amount of coffee liquid can be roughly calculated as about 225 − (15 × 2) = 195 g.

Next, using the above extraction yield formula together with actual measurement by a concentration meter, we will brew a Costa Rica Mirazu Estate Geisha blend coffee bean and see how this cup of coffee performs in extraction.

Costa Rica Mirazu Estate Geisha Blend

Region: Tarrazu, Costa Rica

Estate: Mirazu Estate

Altitude: 1700 m

Processing method: Raisin honey processing

Varieties: Geisha, ET47, SL28, MACIO

FrontStreet Coffee brewing parameters:

Water temperature: 90°C–91°C

Grind size: BG#6m (caster sugar size)

Coffee-to-water ratio: 1:15

Front Street's three-stage brewing method: In the first stage, pour 30 g of water for a 30-second bloom, then pour 95 g (the electronic scale shows about 125 g), finishing the pour in about 1 minute. When the water level drops to 2/3 of the coffee bed, pour the remaining 100 g (the electronic scale shows about 225 g), finishing the pour in about 1 minute 40 seconds. Dripping is completed at 2'00. Remove the dripper and extraction is complete.

This time, the measured concentration of the Costa Rica Geisha blend coffee was 1.34%.

Then the extraction yield is 1.34 × 195 ÷ 15 = 17.42%.

So this cup of pour-over Geisha blend coffee has a concentration of 1.34% and an extraction yield of 17.42%.

From this measurement, it can be judged that this is a cup of pour-over coffee whose concentration meets the standard but whose extraction yield is slightly insufficient. We can use this data to adjust the coffee, for example by changing the ratio and other methods to optimize brewing.

Brief summary

Front Street believes that Golden Cup extraction has benchmark significance for the coffee industry. It has scientifically and standardly organized coffee extraction theory and become a globally used reference template. Front Street's current coffee experiments and offerings are also based on Golden Cup theory. But this is only a reference and does not mean it is absolutely correct. Front Street has always felt that if the coffee you brew, even if it falls within the Golden Cup range, does not taste pleasing, then there is no need to be confined by theory—letting customers drink coffee they like at Front Street is what matters most.

The above content is compiled by CoffeeHunters, a coffee news website.