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How To Fix Your Espresso Tasting Bitter, Sour, or Burnt

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Over-extraction from too fine of grinds and high temperatures are the leading causes of bitter coffee. Dirty equipment is another cause. Keep reading to learn more about balancing your espresso’s taste.

As someone obsessed with espresso, I want to know how to fix any issues that arise when making it. That inspired me to research and write this piece on fixing bitter espresso.

Here’s what I’ll talk about:

Dive in to learn more.

Key Takeaways

  • The main causes of bitter espresso are over-extraction & dirty equipment.
  • Clean oil buildup on coffee grinders & espresso machines often.
  • Avoid using too fine of grinds, tamping too hard, & brewing temperatures higher than 205 °F.
  • Use salt, cream, or sugar as quick fixes for bitter coffee.

4 Causes of Bitter Espresso

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How To Fix Your Espresso Tasting Bitter, Sour, or Burnt 2

A bitter espresso happens because of tannic acid buildup from coffee beans. If your shot lasts too long or is too hot, then there’s a chance this acid will leak into your coffee.

What is tannic acid? Also named tannins, it’s a polyphenolic compound that helps protect plants from oxidative stress, insects, and infected bacteria and fungi.

Over-extraction and dirty equipment are the leading culprits in bitter- or sour-tasting coffee. The first cause refers to overheating your coffee, using too fine of grinds, or too tight of tamping. And dirty machinery requires you to keep your equipment clean.

The following sections will provide specifics of each cause and how to remedy the issues they cause.

Let’s check out the primary cause of bitter coffee.

1. Over-Extraction: Grind Size, Temperature, & Tamping

One of the biggest causes of bitter espresso is over-extraction. It’s a reaction that happens when too much water bonds with your coffee grounds.

Part of what leads to over-extraction is when you use too fine of coffee grounds. Don’t grind your coffee finer than 0.8 mm [1]. Otherwise, you risk poor water flow with your coffee puck.

Bad tamping technique is also another cause of over-extraction. Stick to using the recommended 30 pounds of pressure when tamping. Don’t go over or under this amount. Otherwise, you risk too loose or tight of a tamp.

And don’t use too hot water. Using water that’s hotter than 205 °F will result in scalding your coffee. Stick with using temperatures between 197 °F and 205 °F that the Specialty Coffee Association recommends [2].

Over-extraction is often the result of espresso channeling, which is when espresso flows through your coffee unevenly.

What I mentioned earlier can result in espresso channeling, but there’s also:

  • Uneven tamping: Ensure surface is flat.
  • Grounds distribution: Break down chunks using a WDT tool or a paper clip to prevent air gaps.
  • Overfilling portafilter: Using more coffee grounds than what the machine’s manufacturer recommends.

Other than a bitter-tasting drink, learn whether your espresso is over-extracted by looking at the espresso puck. If it’s soggy, it’s over-extracted. Your puck should have a spongy texture. Not too dry or not too wet.

This next cause will have to do with your machines.

2. Dirty Grinder or Espresso Machine

Oil buildup on espresso machines and coffee grinders from old grounds can lead to bitter-tasting coffee.

If you brew a shot per day, backflush your espresso machine at least once every couple of weeks. Brewing 3 or more shots daily will require you to perform this maintenance weekly. You should also clean your portafilter and group head weekly, no matter the amount you use it.

Then, you’ll want to descale your machine monthly to prevent mineral buildup.

As for cleaning your grinder, use a product like Grindz to strip residual oil from your burrs. Use this product every couple of months. And consider taking a brush to your burrs at least every week or 2.

Not the cause? Think about how long you’re timing your shots.

3. Too Long of a Shot

Don’t brew espresso shots for longer than 45 seconds. That’ll lead to a high risk of the tannic acid from coffee beans leaking into your drink. Giving the beverage its bitter taste.

I see this isn’t the cause, either. The last thing you’ll have to consider is the beans.

4. Bitter Beans

Try using a different bean roast because darker roasts naturally have a bitter flavor profile. Thus, you may opt for light or medium roasts. Or, you may have old coffee beans, which results in bitter-tasting coffee.

Let’s summarize how to fix all the issues mentioned.

How to Fix Bitter Espresso

Fix bitter espresso by addressing your dirty machine or over-extraction:

  • Clean & descale often.
  • Don’t use temperatures more than 205 °F.
  • Avoid grinding beans more than 0.8 mm.
  • Use 30 lbs of pressure when tamping beans; don’t tamp too hard [3].

If you’re reading this, you likely have bitter espresso. Don’t throw it out. Add salt, sugar, cream, or milk to your drink to help remedy the bitter taste.

Use a pinch or 2 of salt. This amount won’t affect your coffee’s underlying flavor but will help eliminate the bitterness. Adding cream or milk—for instance, 2 parts milk and 1 part espresso—neutralizes your drink’s bitterness.

And sugar can add a bit of sweetness to your drink while removing the bitterness. Meanwhile, it’s a safe option for people who are lactose intolerant or are watching their salt intake.

Wait, your coffee doesn’t taste bitter, but it tastes sour? Let’s learn why.

How to Fix Sour Espresso

You may have too coarse of grinds. Stick to using around 0.8 mm fine grinds. Otherwise, you’re letting too much water run through, resulting in a dry coffee puck. This also prevents your machine from having enough time to pull flavors from your beans.

Low water temperatures can also cause sour espresso. Don’t let it fall under 197 °F.

And then there’s using too much coffee. Don’t use more than what your manufacturer recommends. Otherwise, you’ll have bitter-tasting coffee and espresso channeling.

Perhaps you have a burnt taste, instead? I have a fix for that, too.

How to Fix Burnt Espresso

Fix burnt coffee by ensuring your water temperature is under 205 °F, and you don’t use less coffee grounds than the manufacturer recommends.


Don’t scald your milk if you’re making drinks like cappuccinos and lattes. Keep milk steam temperatures between 155 and 165 °F. Otherwise, scorched milk will also give your coffee a burnt taste.

You may not know how to tell whether espresso is too sour or bitter without tasting it. Check out the next section to learn more.

How to Tell if Espresso Is Bitter or Sour

Don’t want to risk tasting sour or bitter coffee? Pull out the portafilter and check your espresso puck. If it’s too dry, it’s likely sour. If it’s too wet, you’ll have bitter coffee. Both of those textures signify under- or over-extraction.

The former leads to sour-tasting beverages; the latter is bitter-tasting.

Your espresso puck should have a spongy texture.

There’s also the look of your espresso. Bitter espresso will have a thick dark brown tint.

FAQs for Bitter Espresso

The following section will cover frequently asked questions about bitter espresso.

Is Espresso Supposed to Be Bitter?

Espresso is not supposed to have a bitter taste. It should have a balanced flavor with a hint of bitterness, but it should not overwhelm your senses.


Over-extraction, bad equipment, darker beans, and running your shot for too long will lead to bitter-tasting coffee. Use a bit more coarse grinds, clean your equipment, distribute grounds, and follow my other tips to avoid bitter espresso beverages.

Do you need help finding an espresso machine to make espresso in general? Explore our recommendations.

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Tim Lee is, as you might have guessed the founder of He is a former barista and a professional web publisher. He has now combined his knowledge and expertise in both subjects to create
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