Extraction is arguably the most important and least understood aspect of coffee brewing. It is essentially the end product of the brew; it is what the hot water takes from the grounds and turns into our favorite morning beverage.
Successful brewing requires using the correct amount of coffee ground precisely to each corresponding brew method. Coffee is then extracted to the correct degree, with the correct time and temperature.
Let’s talk about grind. If you throw whole coffee beans in hot water, not much more than the outside layer is extracted. The bean’s structure is dense which doesn’t allow water to pass through or absorb any of the coffees characteristics. The surface area of the beans must increase so the water can pass through and collect flavor; grinding the coffee helps us achieve this. As you brew, keep in mind that some methods require a coarse grind, like a French press, where others, like espresso require a fine grind.
A perfectly, extracted coffee tastes sweet and ripe, its acidity is defined and complex.
Under- extracted coffee can taste sour, salty, or lack sweetness, and the finish or mouthfeel doesn’t linger. Over-extracted coffee can taste bitter, dry or empty, lacking body. Under-extracted coffee can be fixed by using more water or hotter water, brewing longer, using finer coffee grounds or more coffee grounds. Over-extracted coffee can be fixed by starting over. Experimentation and trial and error is necessary as everyone prefers slight brewing variations. But now you know what coffee is NOT supposed to taste like and have a few tips on how it can be fixed.