The strength of coffee is related to the following factors:

1. The total proportion of soluble substances in coffee

2. Intensity of flavor

3. Mouthfeel, weight or body

The total weight of soluble matter in coffee

The total gravity of the Italian espresso we usually drink is 7%-12%, and the total gravity of drip/hand drip coffee is 1.1%-1.4%. You may ask: "What? Most of it is water?" That's right. Most of the substances in coffee are water. This just shows how strong the taste of coffee itself is. The taste of Italian espresso made by different baristas will vary greatly due to the different total gravity of coffee (the difference between the lowest and highest values ​​is 5 percentage points).

The total proportion of "soluble substances in coffee solution" will directly affect the strength of the coffee flavor, as well as the taste, thickness and body of the coffee.

Intensity of flavor

From the perspective of the proportion of soluble substances, the concentration of Italian espresso is up to 10 times that of drip/hand-brewed drip coffee. This also means that the flavor of the former should be at most 10 times stronger than the latter. But we must know that the intensity of coffee flavor does not increase linearly with the increase in the proportion of soluble substances.

The total weight of "soluble substances in coffee solution" also affects our perception of taste. That is, the higher the total weight of "soluble substances in coffee solution", the worse our ability to identify the taste of coffee. In other words, even if it is the same type of coffee, the taste we perceive may be completely different due to the different total weight of "soluble substances in coffee solution".

A lower gravity coffee doesn’t necessarily mean it’s bland. Sometimes it’s because of the lower gravity that we can pick out more subtle flavors. So a lighter gravity, more delicate espresso can sometimes taste better than a heavier gravity, stronger espresso.

Too high a specific gravity will affect our ability to perceive the original taste of coffee. Too high a specific gravity sometimes prevents you from judging the degree of roasting and the overall quality of the coffee. Only after diluting the coffee can you tell what exactly affects the taste of the coffee.

Mouthfeel, weight and body

The taste of coffee is one of the important factors to measure its quality. When tasting coffee, everyone will judge the taste, thickness and mellowness of the coffee. Due to different social environments and cultural backgrounds, everyone's perception of the taste of coffee is different. But in general, Italian espresso should be mellower and fuller in taste; drip/hand-brewed drip coffee should have a moderate taste and delicate texture.

The following are the adjectives I often use to describe the taste of coffee, from "weak" to "strong". Some people may think that some of these words can also be used to describe the taste, but in my opinion, these words can only be used to describe the mouthfeel, weight and mellowness of coffee.

Suitable concentration ratio

Since everyone has a different perception of coffee quality, it is difficult to come to a conclusion about what is the perfect ratio. Everyone has different preferences for taste and mouthfeel. For me, I think the ratio of coffee should be able to reflect the subtle taste differences of coffee while ensuring moderate taste and mellowness. The following is the concentration ratio I use when making coffee:

1. When making Italian espresso, I will ensure that the soluble matter density is between 7.5% and 9.5% (TDS). Above this range, the coffee will become too bitter. If it is below this range, you have entered the mysterious and unknown "2%-7%" area. For coffee with a density in this range, it is difficult to define whether it is Italian espresso or drip coffee, and its taste is not necessarily worse than ordinary Italian espresso. But before making Italian espresso with a density below 7% for customers, you must taste it in advance to ensure that the taste and mellowness of the coffee meet the standards.

2. When making drip/hand-brewed drip coffee, I usually use a soluble matter ratio of 1.2%-1.4%. If it exceeds 1.6%, the taste of the coffee will become a little strange. As the specific gravity of drip coffee continues to increase, the taste of the coffee also changes. The corresponding ratio of coffee powder to hot water is about 1:12 to 1:17. In addition, there is a concept of extraction rate. Within this specific gravity range, what proportion of coffee substances have you extracted from the coffee powder? Don't panic. Basically, within the usual 2 minutes to 2 and a half minutes at normal water temperature, the extraction rate will fall between 17% and 23%.

Content source: baristahustle | Author/Matthew Perger, illustration and translation by Chenyu Coffee.