Coffee Extraction Tips
I am a craft coffee enthusiast and love exploring the breadth and depth of different coffees from around the world. Early in my coffee journey, I could never remember what notes in the coffee would indicate if the brew was over or under extracted. “Dialing in” your coffee is an important skill in coffee brewing and learning to take cues from the cup can help brew delicious coffee more consistently. What helped me remember extraction cues in the end was learning a little bit more of the science behind brewed coffee and this is what I’ll share with you!
The compounds within green coffee when exposed to the Maillard reaction turn into 100/1000s of compounds that give coffee it’s aroma and flavor. Brewing coffee is the process of extracting the water soluble material present in roasted and ground coffee. Coffee contains caffeine (bitter), acids (sour or sweet), lipids and fats (viscosity), sugars (sweet and viscosity), and carbohydrates (viscosity, bitterness). Under extracted coffee will taste sour and oily. Over extracted coffee will taste bitter and thin. This is because the compounds extracted from coffee are extracted at different rates in the following order; hydrophobic acids and fats, then sugars, and last plant fiber. If you remember what compounds are present within coffee and what flavors they add it is more intuitive to understand if you have an under extracted or over extracted cup.
Given that 30% of coffee is water soluble, the ideal range of coffee extraction is 18–22 percent to only extract the subjective desirable coffee compounds. Your coffees extraction rate depends on many factors like grind size, water temperature, brewing method, etc. Taking a deeper dive into grind size, coffee is ground to expose more surface area for extraction and coffee grind variables are important factors in the brewing process. Ground coffee’s oxidization rate greatly increases leading to a loss of aroma and flavor compounds over time. Grind consistency is important in coffee so that the ground coffee extracts at the same rate over time.
This is just the tip of the iceberg when it comes to brewing better coffee. We didn’t even dive into the most important factor, where the coffee is grown and the producer of the coffee. I encourage you if you’re interested in learning more to do exploration on your own and try to brew as delicious coffee as you can!
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