"Boss, please extract the coffee a bit longer. I want a stronger cup of coffee."
Front Street Coffee believes this is a common scenario for many friends working in coffee shops. Some customers, wanting a more intense-tasting coffee, occasionally make such requests to the shop.
It's not hard to understand, because in the eyes of most consumers, coffee is no different from other beverages—the more liquid extracted, the more intense the flavor. But unfortunately, under normal circumstances, the strength of coffee does not increase with more liquid yield. Why? You can take a look at an experiment Front Street Coffee often shares in articles.With the grind setting unchanged, Front Street Coffee used the same dose of coffee to extract three cups with different liquid yields, then measured their strength and tasted their flavors.Coffee beans: Sunflower Warm Sun Espresso Blend Coffee BeansGrind setting:Galileo Q18 setting 1.0Extraction yield: 38ml, 45ml, 55mlFirst group:20g of coffee extracted 38ml of coffee liquid in 30 seconds, and the measuredTDS valuewas: 11.87%. The coffee'sflavor profile was mainly berry-like sweet acidity and whiskey aroma, accompanied by the rich fragrance of butter cookies, with a finish of vanilla and hazelnut toasted aromas.Second group:20g of coffee extracted 45ml of coffee liquid in 35 seconds, and the measured TDS value was: 10.24%. The coffee's flavor profile showed caramel, cocoa, butter cookies, and whiskey aroma, with a touch of berry-like sweet acidity, and a finish with almond aroma and a slight bitterness.Third group:20g of coffee extracted 55ml of coffee liquid in 38 seconds, and the measured TDS value was: 9.22%, the lowest strength among the three groups. The flavor was also unappealing; although the above flavors all appeared, they were very weak, mainly featuring barley tea and woody notes, with a slight throat-catching bitterness after swallowing.From the results of this experiment, we can see that with the dose unchanged, as the coffee liquid yield increases, the coffee's strength decreases rather than increases. Why? Because the soluble substances in coffee are limited.In a coffee bean, the substances that can be dissolved by water account for only 30% of the bean's weight. Once these soluble substances are fully dissolved, no matter how much more water is used for extraction, the coffee's strength will not increase.Not only that, but we cannot dissolve all of these 30% flavor substances in coffee. Because among these 30% soluble substances, besides the sweet and sour flavors we like, there are also some unpleasant bitter, astringent, and miscellaneous flavors. If we dissolve them out, then the coffee's taste will be like the third cup, showing obvious bitterness and throat-catching astringency, and this is what we often call over-extraction.Therefore, in daily extraction, we control the extraction parameters to dissolve only the flavor substances we need from the coffee beans. So, here's the question: since this method doesn't work, how can we increase the coffee's strength?
Actually, it's very simple! We just need to reduce the amount of water used during brewing / the amount of coffee liquid extracted. Why? You can look at the color changes of the coffee liquid during the extraction process of espresso or pour-over coffee.
The three extraction processes shown above by Front Street Coffee are respectively the beginning, middle, and end segments of the coffee. It can be seen that the color of the coffee liquid is continuously becoming lighter, and by the end, it even looks somewhat whitish. Front Street Coffee used three cups to collect these three segments separately and tasted their flavors.The first cup of coffee liquid tasted the most intense and concentrated among the three espressos, but because the acidity was too prominent, it was somewhat unpleasant; the second cup tasted more balanced, with moderate strength; the third cup, as can be seen, had the lightest color among the three. When drunk, it had a slight bitterness, very weak aroma, and a thin mouthfeel.Both the color and taste performance indicate that the coffee liquid's strength decreases the further it goes. The reason is that the soluble substances in coffee dissolve out in large amounts at the beginning, and as the extraction process progresses, there are fewer and fewer soluble substances in the coffee, so naturally, the strength of the released coffee liquid becomes lower and lower.So as long as we reduce the addition of low-strength coffee liquid, the coffee's strength can be increased. For this reason, reducing the amount of water poured or the amount of coffee liquid extracted has become the main means of increasing coffee strength.For example, when Front Street Coffee brews pour-over coffee, it uses a 1:15 coffee-to-water ratio. If you want a higher strength coffee with the dose unchanged, you can reduce the amount of water poured, such as adjusting the coffee-to-water ratio to 1:14 or 1:13, which can increase the coffee's strength.But note that reducing the water amount will cause theextraction efficiencyto decrease simultaneously. If we want to increase strength while keeping the extraction rate unchanged(i.e., the amount of dissolved substances), then we need to increase the extraction efficiency of other parameters such as grind size, water temperature, and time according to the actual situation. This applies not only to pour-over coffee but also to espresso.One more thing to note is that the above method can only increase the coffee's strength. But if what we want to improve is thein milk coffee(or some other fancy coffee)coffeeflavor intensity, then this method is not applicable! Because the amount of substances in the coffee itself has not increased; only the strength has changed, so this approach cannot amplify the coffee flavor in fancy coffee.If we want to improve the coffee flavor intensity in fancy coffee, we need to increase the proportion of espresso by increasing the dose / reducing the amount of milk or other ingredients, so that the coffee flavor stands out more prominently. The above content is compiled by CoffeeHunters, a coffee news website.
