What Does Coffee Powder-to-Water Ratio Mean? What Does the Professional Term Powder-to-Liquid Ratio Refer to in Specialty Coffee?

Understanding Coffee Ratios: Powder-to-Water vs. Powder-to-Liquid

Powder-to-water ratio and powder-to-liquid ratio are different measurement units used in coffee brewing. Due to their similar names, many beginners easily confuse them, leading to deviations in the flavor of extracted coffee. Therefore, FrontStreet Coffee would like to share again today the differences between powder-to-liquid ratio and powder-to-water ratio.

Understanding Ratios

First, let's talk about ratios! A ratio is a mathematical term that indicates the comparative relationship between quantities. Once we understand this term, we can directly understand the meaning of powder-to-water ratio and powder-to-liquid ratio in coffee terminology.

The powder-to-water ratio refers to the ratio between coffee grounds being extracted and the water used for extraction. For example, the commonly mentioned 1:15 means that for every 1g of coffee grounds, 15ml of water should be used for extraction. The powder-to-water ratio has a very wide range of applications. It can be said that except for some coffee brewing methods where water injection cannot be measured, most coffee extractions are more suitable for using the powder-to-water ratio. This is because: first, it's more convenient to calculate; second, it allows better control over the injected water amount to extract the flavor compounds we want; and third, it reduces errors caused by different water absorption rates of coffee beans.

Powder-to-Liquid Ratio

Now let's talk about the powder-to-liquid ratio. The powder-to-liquid ratio means the ratio between coffee grounds being extracted and the extracted coffee liquid. For example, 1:12 means that 1g of coffee grounds needs to extract 12ml of coffee liquid. This sounds similar to the powder-to-water ratio, but in reality, the meanings are quite different because they are not units that can be equivalently converted.

The Conversion Relationship

If we use 225ml of hot water to brew coffee, we won't get an equal weight of coffee liquid in the lower pot, because the coffee grounds will absorb some of the water, resulting in less coffee liquid dripping into the lower pot than the hot water injected! Basically, coffee grounds will absorb about twice their own weight in water. We can directly use this principle to roughly calculate the weight of coffee liquid, which is also the conversion formula between powder-to-water ratio and powder-to-liquid ratio.

For example, if you use 225ml of hot water to extract 15g of coffee grounds, then the 15g of coffee grounds will absorb about twice their weight in water, which is about 30ml. When we subtract 30ml from 225ml, we can get the approximate weight of coffee liquid, about 195ml. Why do we use "about" and "approximately"? Because the water absorption rate of coffee beans is not absolutely twice their weight, it's just closer to that value.

Applications and Common Mistakes

Generally speaking, the powder-to-liquid ratio is more commonly used in espresso extraction, because espresso machines cannot measure the hot water used during extraction, so the powder-to-liquid ratio needs to replace the powder-to-water ratio. However, this doesn't mean that other coffee extraction methods don't use the powder-to-liquid ratio. Some people making pour-over coffee also use the powder-to-liquid ratio to replace the powder-to-water ratio for measurement. But often, the concern is that some beginners might mistake the powder-to-liquid ratio for the powder-to-water ratio when using it for measurement.

For example, a 1:15 powder-to-water ratio converts to about 1:13 to 1:13.5 powder-to-liquid ratio. If beginners directly think that the powder-to-water ratio is the same as the powder-to-liquid ratio, and measure a 1:15 powder-to-liquid ratio when extracting coffee, then加上 the two portions of hot water absorbed by the coffee grounds, it can be calculated that the injected hot water will reach a 1:17 powder-to-water ratio. When the number for water in the powder-to-water ratio is larger, it means more hot water will be used for extraction, and the concentration will be relatively lower (and vice versa). This practice not only dilutes the coffee concentration but also extends the extraction time due to the increased water amount, causing the coffee to extract some substances you might not want.

Conclusion

Therefore, the differences between powder-to-liquid ratio and powder-to-water ratio must not be confused. FrontStreet Coffee does not recommend that beginners use the powder-to-liquid ratio to make pour-over coffee, because first, it's difficult to control the injected water amount, and second, stable extraction cannot be achieved. When problems occur and it's difficult to find the root cause, it's a very headache-inducing thing for beginners. Therefore, it's best for beginners to stick with the powder-to-water ratio when making pour-over coffee.

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