Understanding Coffee Extraction: The Key to Better Brews

What You'll Learn

• What coffee yield is and how it relates to extraction
• How yield affects your coffee's taste, strength, and mouthfeel
• Simple ways to measure and adjust yield for better coffee

Hey there, coffee lovers! Ready to dive deeper into the world of coffee yield? Don't worry, we'll keep it approachable. By the end of this post, you'll have new tricks up your sleeve for making even better coffee. Let's get brewing!

Coffee as a Solution

First, let's think about coffee in a new way: as a solution. Just like sugar dissolves in water, parts of coffee grounds dissolve in water to create your brew. This coffee solution has three main characteristics we'll explore:

1. Strength: How much coffee is dissolved in the water
2. Yield: How much brewed coffee you end up with
3. Taste: The flavors you experience in your cup

Understanding these helps us make better coffee. Let's dive in!

Understanding Coffee Strength

Strength refers to how concentrated your coffee is. It's related to Total Dissolved Solids (TDS), indicating what percentage of your beverage is composed of coffee particles. While exact measurement requires specialized equipment, you can think of strength as how "intense" your coffee tastes. Usually for drip coffee this value is around 1.5%, meaning that 1.5% of the content of your cup is coffee particles. (Espresso TDS values are in the 8-12% range)

Extraction, Yield and Extraction Yield Explained

Yield, in the context of coffee brewing, is simply the total amount of brewed coffee you end up with after the brewing process. It's typically measured in weight (grams) or volume (milliliters).

For example, if you start with 18 grams of coffee grounds and end up with 36 grams of espresso, your yield is 36 grams.

The brew ratio, which is often confused with yield, is the relationship between the amount of coffee used and the yield. In the example above, the brew ratio would be 1:2 (18g coffee to 36g yield).

Extraction refers to the process of dissolving flavor compounds from the coffee grounds into water. When you brew coffee you are trying to optimize the extraction process. Given a fixed brew ratio, by changing brewing parameters, you will change extraction yield.

Extraction yield is the mass of dissolved coffee ground, expressed in percentage of the initial coffee’s mass. For instance if you start with 18gr of grounds, a 10% extraction yield means 1.8gr of coffee grounds dissolved in water. Ideal values of extraction yield range between 18% (under-extracted) and 22% (over-extracted).

While professionals use tools to measure exact extraction percentages, at home, we focus on yield, brew ratio, and most importantly, taste. A well-extracted coffee should have a balance of flavors, without tasting overly sour (under-extracted) or bitter (over-extracted).

For more details, you can refer to Wikipedia.

How Yield Affects Your Cup

1. Flavor: Lower yields often bring out more acidity, brightness^[1]  and clarity in flavors. Higher yields can highlight deeper, richer notes.
2. Strength: Less water (lower yield) makes stronger coffee. More water (higher yield) makes it weaker.
3. Mouthfeel: Lower yields usually give a thicker, more syrupy feel. Higher yields tend to be lighter and more tea-like. Think of the difference between a shot of espresso and a cup of drip coffee – that's yield at work!

The Relationship Between Yield, Strength, and Taste

These three factors are like a balancing act. Changing one affects the others. For example:

• Increasing yield (adding more water) can lower strength but might improve extraction if your coffee was under-extracted, meaning it tastes sour or lacks complexity because not enough flavor was dissolved.
• Decreasing yield can increase strength but might lead to under-extraction, resulting in sour or sharp flavors from insufficient flavor development.

The goal is to find the "sweet spot" where yield, strength, and taste all come together for a delicious cup.

Measuring and Adjusting Yield

To accurately measure your coffee yield, you'll need a good scale. We recommend investing in a coffee scale or a kitchen scale with 0.1g precision. This level of accuracy is crucial for consistency in your brews.

1. Use your scale to weigh your ground coffee and brewed coffee.
2. Calculate your brew ratio: brewed coffee weight ÷ ground coffee weight.
3. Start with a 1:2 ratio for espresso or 1:15 for drip coffee.
4. Adjust based on taste:
   1. If too strong or bitter, increase yield (add more water)
   2. If too weak or sour, decrease yield (use less water)

Describing Your Coffee: Tasting Notes

Learning to describe your coffee helps you understand what you like and how to improve your brew. Here's a quick guide:

• Weak coffee: Watery, thin, empty
• Strong coffee: Heavy, intense, overwhelming
• Well-balanced coffee: Rich, full-bodied, smooth

Keeping a Brewing Journal

Start a coffee journal to track your brews. Note down:

• Coffee type and roast date
• Grind size
• Coffee dose and water amount
• Brew time
• Tasting notes

This will help you replicate great brews and learn from the not-so-great ones.

Coffee Nerd Corner: The Complexities of Extraction

If you read all the way through, then welcome to the coffee nerds club! We barely scratched the surface, but there is one more thing that you should understand to unlock the secret of the perfect extraction.

Not all coffee compounds dissolve at the same rate! Acids are extracted early in the brewing process, while balancing compounds such as sugars and bitter substances are extracted later. This is why under-extracted coffee is sour and over-extracted coffee is bitter. And this is why brewing time is often used as a parameter you can control!

While this complicates brewing A LOT, knowing this allows you to experiment more. When you brew a new coffee we recommend starting with a 4min brewing time for V60 and a 35 seconds brewing time for espresso.

Understanding this extraction process helps explain why adjusting brewing time can significantly impact flavor.

Conclusion

Understanding yield and extraction is just the beginning of your journey to better brews. In our next post, we'll introduce you to the Coffee Compass - a powerful tool to help you navigate the world of extraction and flavor. Stay tuned to learn how this simple guide can transform your troubleshooting skills and lead you to the perfect cup, every time!

Happy brewing, coffee lovers! With these tips, you're well on your way to consistently great coffee at home.

Footnotes

1. When we talk about acidity in coffee, we're referring to a desirable brightness or liveliness in the cup, not sourness. Brightness can be viewed as “good acidity”, an acidity that pops light grapefruits, pineapple or other fruit that is slightly under ripe. Sourness is usually a sign of under-extraction and is generally considered a flaw.