The Secrets to Perfect Coffee Extraction

You've probably encountered the word "extraction" when learning about brewing coffee, but what is it really? To put it simply - extraction is the chemical process behind brewing coffee. To put it a little less simply, it's the means by which hot water bonds with molecules from your ground coffee to liquefy them and give you that delicious cup. To put it even less simply... well, read on!

Compounds and Flavor Profiles

There are several different types of molecular compounds that hot water extracts from ground coffee beans. First, there's acids and fats. Acids are the fastest for the water to bond with as they are the simplest compounds on the list. They add sour notes to coffee - but that doesn't mean they're all bad! You often need that bit of sourness to balance out the cup (more on this later). Fats are next, and they liquefy a bit later than acids due to their higher complexity. Fats add body to coffee and help keep the drink from feeling thin. Next there are sugars, which perhaps obviously give you those sweeter, fruity notes. Finally, the most complex compound are plant fibers, which add bitter, earthy notes. Like with sour acids, that bitterness is needed to balance out the cup!

Extraction and Taste

In order for your cup of coffee to taste good you'll want to extract just enough of each of the compounds discussed above. If you under-extract then you'll be left with lots of those acids, but not enough of those fats, sugars, and plant fibers. Under-extraction is usually caused by temperatures that are too low or grounds that are too coarse. If you think about it, it makes sense: lower temperatures have a harder time bonding with molecules, and coarser grind size results in more surface area and quicker contact between the water and the grounds. The result is that the water bonds with the acids, but not enough of the other compounds that take longer to bond. Over-extracted coffee tastes too bitter, and is usually the result of too much heat or grounds that are too fine (which can choke the filter and slow flow rates). Essentially, the opposite issues from under-extraction occur and cause the water to bond with too many plant fiber compounds, overpowering the rest of the molecules with those bitter, earthy notes.

A perfectly extracted cup offers balance between the different compounds and flavor profiles that come with them.

Extraction Tips

The secret to perfect coffee extraction starts with grind size. You'll want to find a grind setting that allows for just the right flavor profile, but doing that takes practice. For some brew methods and popular grinders you can find good settings starting points if you look online or in your manual. From there you'll need to adjust your grind from brew to brew, going coarser if it's too bitter or finer if it's too sour. Over time you'll get better at this process, which we call "dialing-in."

It's also important to use the proper amount of coffee and water. We suggest starting with a 1:16 coffee to water ratio (by weight) for slow brew methods and a 1:2 ratio for espresso. 

Finally, you'll want to ensure that your water is in the 195-205 degrees Fahrenheit range. Each of these variables can be tweaked for better flavor once you have a good baseline.

Since each coffee is different on a molecular level, you'll have to adjust your parameters with different beans. This is the fun of coffee as a hobby, but don't worry, it's not hard to lock down your dialing-in process on a basic level so that you can get brewing some coffee you'll love.

And that leads us to the real secret behind perfect coffee extraction - practice makes perfect. It's important to have a grinder that can grind consistently, a hot water kettle or coffee machine with consistent temperature control, and properly dosed beans and water, but even with the best gear in the world you'll still need practice to brew the perfect cup.

Check out our video below for more tips!