What Exactly Is Coffee Extraction?
Class is in session, so maker sure your portafilters arm warm and tampers are in hand. Extraction is a word that’s thrown around and used in a multitude of ways, but what does it mean for your morning routine and how does it impact the flavor of your espresso? Today we will discuss extraction fundamentals: what extraction is and how to achieve better extraction. We’ll break down this essential process to reveal how it shapes the flavors we enjoy every morning. We use a refractometer in our simple demonstration, but all you really need is to trust your taste buds.
What Is Coffee Extraction?
In simple terms, coffee extraction is the process of pulling soluble compounds out of coffee grounds using water. These compounds are responsible for the coffee’s aroma, body, and flavor. Achieving the right balance is key: under-extraction leaves your coffee sour and weak, while over-extraction makes it bitter and unpleasant.
The compounds in coffee dissolve at different rates:
- Acids and Bright Flavors: Extracted first, giving coffee its lively and tangy notes.
- Sweetness: Follows next, creating balance and depth.
- Bitterness: Extracted last, adding body but potentially overpowering if overdone.
The goal is to hit the not-so-mythical "sweet spot," where acids, sweetness, and bitterness harmonize into a well-balanced beverage.
Key Variables That Affect Extraction
The factors below are some of the main influences on coffee extraction. Understanding, troubleshooting, and experimenting with them will help you become a more well-rounded barista and improve your coffee as your skills develop.
- Grind Size determines the surface area exposed to water. Finer grounds extract faster, leading to over-extraction if not dialed in properly. Coarser grounds, however, require more time to extract fully.
- Water Temperature between 195°F and 205°F (90°C to 96°C) is generally ideal for brewing. Too hot, and you risk over-extraction; too cool, and the coffee may taste flat and under-extracted.
- Brew Time is the easiest variable to alter, but it’s generally much better to shoot for an expected liquid yield rather than a hard focus on extraction time.
- Coffee-to-Water Ratio: also called a brew ratio. For filter coffee, the golden ratio is often cited as 1:16—1 gram of coffee for every 16 grams of water. Remember that this is dependent on the coffee and on personal taste. For espresso, we’re working within a range from 1:1 to 1:3, but this is not a hard and fast rule. What’s most important is that you start with a brew ratio. You wouldn't want to make a traditional bouillabaisse without a recipe if you've never made one.
- Water Quality: water is the medium for extraction, so its quality is of the utmost importance for both the longevity of your equipment and the flavor of your coffee. We recommend that your water be filtered and soft. Read more about the importance of water.
Coffee extraction is a complex process, but with a little practice, it will begin to become second nature with each shot that you taste. Do you need some coffee coaching, or you just want to chat coffee? Please contact us, we'd love to talk!