You brew a cup of coffee, it smells great! You take a sip and yuck; it's salty, sour, and flavorless. If your coffee tastes like this, then you have under-extracted coffee. Under extraction happens to the best of us, and it's nothing to be too worried about. There are simple reasons and fixes you can learn about so that the next brew will be perfectly extracted.
What is Under Extracted Coffee?
Simply put, coffee extraction is coffee brewing. When you pour hot water over coffee grounds, it extracts the soluble components of coffee and becomes what you know as coffee. First, the water pulls out acids and sugars, then the solids and oils, and finally, bitter components. If you extracted your coffee well, then you'll end up with coffee that is flavorful, crisp, and balanced. In contrast, under extracted coffee tastes sour, salty, and thin.
There are several factors that can cause under extraction, including water temperature and amount, coffee grind size, and brew time. We'll go into detail about how exactly they contribute to your coffee extraction.
How to Fix Under Extracted Coffee
Before we tell you how to fix your under-extracted coffee, you should first troubleshoot what exactly went wrong in your brew. Did you use too little water? Was the water not hot enough? Was the coffee ground too coarsely? Once you figure out what didn't go right, you can efficiently and effectively fix your next brew.
Grind Your Coffee Finer
If you're using coarse coffee grounds for a brewing method other than cold brew or the french press, you might want to grind your coffee smaller. Extraction is heavily reliant on the surface area of your coffee grounds. The more surface area the water has to interact with, the more flavor you will pull from your coffee beans. Larger grounds have less surface area compared to smaller grounds, so you won't be able to extract as much flavor. We recommend grinding fine to medium for a moka pot or Aeropress, and medium to coarse for a pour over. Experiment with different grinds to figure out what you like best. If your coffee tastes too bitter, your coffee is too fine. If it tastes sour, it's too big.
Use Hotter Water
Most coffee brews need a water temperature of at least 195 degrees Fahrenheit in order to properly extract the oils and flavors from the coffee. Don't let your water cool off for too long once it boils as it could affect your brew. The only exception to this is cold brew, as it uses room temperature or cold water. Be careful not to use water that is too hot either (over 205 degrees Fahrenheit) as your coffee will taste burnt and very bitter.
Since extraction is based on the amount of contact the water has with the coffee grounds, the brew time is important. If you have a very short brew time, chances are it's not long enough to properly extract the yummy solubles fo coffee. If you brew too long, you'll end up over-extracting your coffee and end up with very bitter coffee.
Each brew method has its own recommended brew time, for example, pour over coffee has a brew time of around 2-3 minutes while french presses can be up to 5 minutes.
Fix Your Coffee to Water Ratio
Maybe you are using too little coffee or not enough water. Extraction is all about water and coffee contact, so the amounts of both are essential to a good extraction. The golden ratio for coffee brewing is 1 gram of coffee to 15 grams of water. You might find that you like more or less coffee or water, but generally this is the standard that most people use. Too little coffee or too much water and your coffee will taste diluted.
Evenly Distribute Your Coffee
This tip is one that is often overlooked, but could make a big difference in your next brew. Often, when we add coffee into a filter or brewing tool it ends up in a mound. If you pour water onto a mound of coffee, some areas of the coffee won't be as extracted as others resulting in a flavorless brew. You want to make sure that your coffee is distributed evenly so that all the coffee grounds get a chance to make contact with the water.
Brew Specific Fixes
Cold Brew Coffee
Cold brew isn't excluded from being under extracted. Cold brew requires a very coarse grind, as if it is too fine and it runs the risk of being over extracted and bitter. If you taste your cold brew and it tastes flavorless or sour, you most likely need to leave it to brew for longer. Cold brew needs at least 16 (and up to 24) hours to get a good flavor.
Did you make under extracted coffee in a french press? Check your coffee grind size and make sure that it is coarse. The average brew time for a french press is around 3 to 5 minutes and usually uses a 1g coffee to 12g water ratio.
Pour Over Coffee
Pour over coffee is one of the most tricky coffee brews to nail down, as it has so many factors that influences the coffee flavor. Make sure your grind size is medium to coarsely ground, as too big won't allow the water to extract much flavor and too little will be over extracted. What is most crucial about this brew method is the brewing technique itself. There are a variety of ways to achieve this goal, but the general sequence is the blooming stage and the rest of the water pouring.
Espresso is also a very difficult brew to get right, as it's brewing time of 30 seconds leaves little to no room for error or leeway. Most of the time, under-extracted espresso comes from coffee ground that are too big, uneven tamping, or coffee beans that are too fresh or old.
Watch this video for an in-depth explanation on fixing espresso pulls:
Ways to Use Under Extracted Coffee
Let's say you just can't save your under-extracted coffee, or you have more than you want to drink. Here are some ways you can use that coffee without throwing it away:
- Use as coffee ice cubes
- Use in a blended coffee drink
- Add to a very strong coffee
- Cook or bake with it
- Water your plants (only a very, very diluted coffee though! too much acid is not good for plants)
At the end of the day, no one likes to waste good (or potentially good) coffee. We have shared some creative ways to use leftover, under-extracted coffee, and tips that may help make a better brew next time. Under extracted coffee is nothing to be embarrassed about, and often it can help you understand coffee brewing better.
Get better tools to make a better brew by shopping our brew gear section. Invest in a quality grinder and coffee maker to ensure your favorite beans are brewed to perfection each time.