by Erin Marissa Russell
Ready to learn about over extracted coffee? The secret to a perfect cup of coffee is balancing the brewing time, water temperature, and grind size so that your coffee is neither over extracted nor under extracted. But in order to do that, you need to know what over extracted coffee tastes like, why it happens, and how to make adjustments if your coffee is over extracted.
What Is Over Extracted Coffee?
First, let’s talk about how extraction works. Simply put, extraction is how coffee and water interact during the brewing process to turn coffee grounds and water into a tasty hot beverage. All the flavor we love in coffee comes from acids, compounds, and oils that are locked inside the coffee beans.
Those flavorful acids and oils get extracted into the water when the coffee is brewed, transforming the hot water and coffee grounds into coffee. An over extracted cup is just what it sounds like: a brew that has too much of the coffee compounds in it to be palatable.
By the same token, under extracted coffee is the opposite: a brew that’s lacking in flavorful oils and compounds. Another way to look at it is that under extracted coffee hasn’t gotten enough flavor from the coffee grounds for one reason or another.
What Does Over Extracted Coffee Taste Like?
When your coffee is over extracted, you’re sure to notice by the taste. Over extraction is responsible for that too-strong, bitter, or even burned flavor you may have noticed in an unsavory cup or two.
The bitterness is caused by chemicals that emerge from the coffee, and those with unsavory flavors are freed from the beans after the tasty oils and acids have been depleted. Noticeable bitterness may also come from using beans that were roasted for too long. You may also notice a dryness or astringency to the coffee if it is over extracted.
On the other hand, an over extracted cup of coffee can taste flat and lack the nuances of flavor that make coffee so delicious. While under extracted coffee can also mimic this symptom and taste dull, weak, and thin or watery, an under extracted cup like this will have a sour flavor that isn’t present with dullness from over extraction. Using beans that are old or stale is another potential reason for thin, flat flavor.
The hallmarks of under extracted coffee are sour flavor, lack of sweetness, and a finish that’s disappointing and far too quick compared to your usual cup. Under extracted coffee can even have a slightly salty taste.
A balanced extraction, on the other hand, doesn’t suffer from any of these problems. It’s naturally sweet and ripe. The ideal extraction has a clear flavor, along with a bit of complex acidity (but not too much). An ideal brew will also have a long, tasty finish.
To review, here are the signs of over extraction:
- Overly bitter flavor
- Dryness or astringency
- Too-strong taste
- Flat, dull taste not paired with the sourness that indicates under extraction
Identifying an over extracted cup of coffee by taste is the easy part. Next, you’ll need to make adjustments to your brewing process to correct for the over extraction.
Common Causes of Over Extracted Coffee
Try to avoid these common pitfalls that can lead to over extracted coffee.
- Brewing with too much water. Continuing to pour water over the coffee grounds or steeping them past the sweet spot can extract more than just the good stuff into your cup.
- Moving the coffee around too much by stirring, shaking, or otherwise agitating the brew. The more things are moving around, the quicker your coffee will be extracted, so the quicker you’ll get unsavory flavors in your brew.
- Failing to remove the filter or grounds can let coffee steep past its ideal point. Make sure to remove the filter from pour-over setups or automatic drip coffee makers as soon as the water appears to have drained out so that the water doesn’t continue to be extracted into the coffee. In mechanisms like French presses, pour the coffee out into cups or a carafe (preferably something that will keep it warm) after the brew time has finished.
- Brewing for too long. Keeping the brew going past the ideal point can start to pull out those bitter flavors or lead to a dull, flat cup. Here’s a list of the best brewing times for each preparation method.
- Automatic drip system: About five minutes
- French press: Two to four minutes
- Pour over: Three to four minutes
- Espresso: 20 to 30 seconds
- Cold brew: About 12 hours
- Grinding the coffee beans too finely. The more finely your coffee beans are ground, the more quickly the oils and acids will be extracted from them. Here’s a guideline to follow for the appropriate grind size to use for different preparations.
- French press: Coarse, very chunky grind
- Chemex or other pour-over: Medium coarse, less chunky grind
- Drip or machine drip: Medium grind, like kosher salt
- Siphon: Medium-fine grind, between table salt and kosher salt
- Aeropress or Espresso: Fine grind, like table salt
- Turkish coffee: Very fine grind, like powdered sugar
Is My Coffee Over Extracted?
Here’s a list of questions you can use in helping to identify over extracted coffee. If you answer yes to any of these questions—even just one of them—your coffee may be over extracted.
- Did you brew your coffee for longer than the ideal brewing time listed for your preparation method?
- Did your water reach a higher temperature than the one that’s listed for your preparation method?
- Did you agitate the brew by stirring, shaking, or mixing?
- Did you use more water than your preparation method calls for?
- Are the coffee beans ground more finely than is recommended for your preparation method?
- Did you fail to remove the filter or grounds after the brewing was complete?
If your answer to any of these questions is yes, there’s a good chance your coffee is over extracted.
How to Fix Over Extracted Coffee
Unfortunately, there’s not a lot you can do to fix a cup of coffee that’s over extracted after it has already been brewed. However, you can make adjustments to your brew so your cup is perfect for next time.
- Calibrate your settings to what’s recommended: Use the recommended brewing time, brewing temperature, and grind size for the preparation method you’re using.
- Do not stir, shake, mix, or otherwise agitate the brew while it’s steeping.
- Keep an eye on your brew and remove the filter or grounds after brewing is complete.
Since you’ve recalibrated your settings to the brewing time, water temperature, and grind size recommended for your brewing method, if you taste any of the signs of an over or under extracted brew, then you can begin to make adjustments. If your coffee’s over extracted, try reducing the brew temperature, lessening the grind size, or brewing for a shorter time period. Continue making adjustments until your brew is the best it can be.