3 Signs Your Coffee Is Under Extracted

Written by: Garrett Oden

under extracted coffee

Want to learn how to master your coffee in a way most people don’t understand? Allow me to introduce you to the basics of coffee extraction. Extraction is the most important and least understood part of coffee brewing.

Most coffee lovers have no idea what extraction means. But if you want to brew the best coffee you possibly can, you need to know what it is and how to manipulate it.

For this blog post, I’ll guide you through under extraction. I’ll tell you what it is, how to taste it, and what to do about it when it happens.

You’re on your way to mastering your coffee in a powerful, practical way that most have no idea about. And the best part is…

It’s not hard at all.

Read: Why Fresh Coffee Is The Best Coffee

A Brief Primer On How Extraction Works

Extraction isn’t just a part of coffee brewing. It is coffee brewing.

When you make coffee, the water extracts things from the coffee grounds and dissolves them. That’s how you get brown, liquid coffee.

During the first few moments of brewing, the water extracts acids and sugars. Then it pulls out dissolved solids and oils. And then, finally, the more bitter compounds that round out the flavors.

A balanced extraction is rich with an array of flavors, pleasantly aromatic, crisp with a balanced acidity, and even has a hint of low-noted bitterness to round out the flavor profile.

Under extracted coffee is the result of coffee that hasn’t yet reached that sweet spot of balance and flavor. It’s what happens when the water isn’t able to pull out enough stuff from the grounds.

Remember that extraction isn’t like a light switch that you flip on and off. It’s a long, slow progression. Under extracted can be slightly noticeable, it can be painfully (literally) obvious, or somewhere in between.

Read: 3 Signs Your Coffee Is Over Extracted

Let me tell you the three major signs of under extraction so that you can make the changes you need to brew more flavorful and balanced coffee.

1. Overpowering Sourness

Acids in coffee are easily misunderstood. The world’s best coffees are acidic, and that’s a good thing.

Acids, when balanced, bring life and zing to the coffee flavors. They highlight and compliment flavors to create complex experiences. They can even come with their own incredible flavors, like strawberry, orange, or green apple.

But this isn’t the kind of acidity we’re talking about.

We’re talking about coffee that’s sour, overly tangy, and sometimes painfully sharp. This is acidity un-checked.

Under extracted coffee often has a biting sharpness on the sides of your tongue. And, when it’s really bad, it can even make you want to pucker your lips like when you eat a sour candy.

I once had a shot of espresso that literally burned when I swallowed because it was so under extracted. It was so sour and intense that it made my eyes water.

Read: How To Taste Coffee Acidity

Sour coffee is coffee that has all the normal acids, but nothing else to balance them out. It’s not necessarily “overly acidic”, it just doesn’t have anything to round out the acids so that they’re pleasant and balanced.

under extracted coffee

This leads me to the next sign.

2. Thin Flavor

Under extracted coffee hasn’t had all the yummy flavors pulled from the grounds yet. Most of the sugars, oils, and balancing bitter notes were left in the grounds instead of being pulled into the water.

This is what leads to that unpleasant sourness, but also to a lack of flavor. Under extracted coffees taste incomplete, unfinished. You want to enjoy the full range of flavors that the coffee features, but you’re just not getting it.

Note: this is not to be confused with the dull, lifeless quality of over extracted coffee. That can be described as dead and boring, but this is more so underdeveloped.

Read: The Easy Guide to Coffee Bean Storage

With under extraction, it’s not lifeless (those unchecked acids could shock anything back to life). It’s just thin, incomplete, and not all there.

3. Saltiness

Wait, saltiness? Salty coffee??

It sounds weird, but yes, it’s real.

Coffee that’s particularly under extracted can have a salty flavor that pokes out from the sourness. It doesn’t exactly taste like you poured table salt into your mug, but it’s close.

When I was first getting into coffee, I thought I tasted saltiness in my under extracted coffee, but I figured it was probably all in my head. Then, when I became a barista and learned from more experienced coffee lovers, I learned that it wasn’t just me.

Saltiness in under extracted coffee is a real thing.

Read: How Much Should You Pay For Coffee Beans?

Common Mistakes That Lead To Under Extracted Coffee

Under extraction is the result of several different brewing mistakes.

Let me walk you through them so that you can identify the causes and make the proper adjustments to brew better coffee.

You don’t brew long enough. If you don’t give the water enough time to pull out just the right amount of acids, oils, sugars, and other things from the grounds, you’ll end up with under extracted coffee. Those acids won’t be balanced out by anything, which will lead to sourness.

For example, if you brew a french press for four minutes and notice your coffee has some sharp sourness, you can easily add a minute to the brew next time to bring back some balance.

Your water isn’t hot enough. The hotter your water, the faster it extracts things from the grounds. If your water isn’t within about 10 degrees of boiling, you’ll likely end up with under extracted coffee.

You grind too coarsely. The coarser the grind size, the longer it takes to achieve a balanced extraction. If your setting is too coarse, your water won’t be able to extract everything it needs to. A slightly finer setting may fix the problem.

You don’t use enough water. If you’re making a pour over and run out of water before you’ve reached the golden coffee to water ratios, you’ll likely end up with under extracted coffee.

under extracted coffee

For example, if you’re trying to pour 550g of water but the kettle is empty after only 520g, the things left in the coffee that you want (bitter compounds, oils, sugars) will just stay in the grounds. Stick to the golden ratios (and make sure you have enough water in the kettle).


Under extracted coffee is everywhere and most people don’t realize it.

There will be times you under extract (there’s no shame, we all do it sometimes), but as long as you remember these key signs and brewing mistakes, you’ll be able to adjust and brew better coffee.

Of course, this knowledge and newfound skill will go to waste if you brew with low-grade, stale beans. If you want to brew the best coffee you can, you have to start with the best beans you can find.

Check out our JavaPresse Coffee Club. Every two weeks we send out freshly roasted, specialty-grade beans to our subscribers. We source our beans from the best coffee farms in the world and are thrilled to share our richly flavorful coffees with you.

Trust me, once you taste fresh, flavorful, and balanced coffee acids, you’ll never go back to stale store-bought beans again. Check it out!