Why Does My Espresso Taste Bad?

Henning Schlueter

Jul 30, 2025

6 min read

Updated: Sep 19

Sour? Bitter? Watery? Running too fast? Here's how to diagnose a bad espresso—and what to change first.

You buy good coffee. You warm up the espresso machine. Grind the beans, pull the shot, take a sip…

And it's horrible.

Sour. Bitter. Watery. Maybe all three.

Before blaming the coffee, throwing your grinder out of the window or spending €3,000 on a new espresso machine, there are a few things worth checking.

Espresso is surprisingly sensitive. A small change in grind size, dose or yield can turn a terrible shot into a very good one.

The good news is that most bad espresso can be fixed.

So, let's troubleshoot it.

☕ The quick espresso fix

Your espresso…	Most likely cause	Try this first
Tastes sour	Under-extracted	Grind finer
Tastes bitter/dry	Over-extracted	Grind coarser
Runs too fast	Grind too coarse	Grind finer
Runs too slowly	Grind too fine	Grind coarser
Tastes weak/watery	Ratio/extraction issue	Use less water / check dose
Tastes harsh/burnt	Dark roast / high temperature	Lower temperature or try a lighter roast

And before doing anything else:

Change one thing at a time.

If you change the grind, dose, temperature and yield together, your next espresso might taste better—but you'll have absolutely no idea why.

First, a little bit about extraction

Espresso is basically hot water being pushed under pressure through finely ground coffee.

Sounds simple.

Unfortunately, we've managed to make it considerably more complicated than that.

As water passes through the coffee, it dissolves different compounds. Very roughly speaking, some of the brighter, acidic flavours are extracted earlier, followed by sweetness and balance, while longer extraction can increasingly bring out bitter and drying flavours.

Think of it something like this:

Sour & sharp → Sweet & balanced → Bitter & dry

This is a simplification. Coffee extraction is considerably more complicated and somebody with a refractometer will probably already be getting upset with me.

But for fixing your espresso on a Sunday morning, it's useful.

😖 My espresso tastes sour

A sour espresso usually means we haven't extracted enough from the coffee.

This is especially obvious when the espresso tastes aggressively sharp rather than pleasantly fruity or acidic.

There's an important difference.

A good Ethiopian coffee, for example, might naturally have a bright acidity. That doesn't mean it's under-extracted.

But if the shot makes you pull the same face as biting into a lemon, we probably have some work to do.

1. Grind finer

This is the first thing I would change.

A finer grind creates more resistance to the water, generally slowing down the shot and increasing extraction.

Make a small adjustment.

Pull another espresso.

Taste it.

Better?

Good. You're heading in the right direction.

2. Check your recipe

A useful starting point for espresso is roughly:

18g coffee in → 36–40g espresso out

That's around a 1:2 ratio.

It is not a law.

You will not be arrested by the coffee police for pulling 42g.

It's simply a useful place to start because it gives you something repeatable to work from.

3. Try a little more water

If the espresso is still sour, you can allow slightly more water through the coffee.

For example:

18g in → 36g out

might become:

18g in → 40g out

Taste again.

4. Check your temperature

If your machine allows temperature adjustment, around 92–93°C is a good starting point.

Lighter roasted coffees can sometimes benefit from slightly higher temperatures because they're generally more difficult to extract.

But again: change one thing at a time.

😬 My espresso tastes bitter

Now we have the opposite problem.

If the espresso tastes unpleasantly bitter, harsh or leaves your mouth feeling dry, you may be extracting too much.

So we start moving in the other direction.

1. Grind slightly coarser

This is normally the first thing I'd try.

Don't make a huge adjustment.

A small change to your grinder can make a surprisingly large difference to espresso.

2. Shorten the shot

If you're currently making:

18g in → 45g out

try stopping closer to:

18g in → 36g out

Then taste.

You may find the espresso becomes sweeter and fuller.

3. Try a slightly lower temperature

Particularly with darker roasted coffee, lowering the temperature can sometimes reduce harshness and bitterness.

4. Look at your beans

Sometimes your espresso tastes bitter because the coffee itself has been roasted very dark.

Look at the beans.

If they're extremely dark and covered in oil, some of that smoky, roasty bitterness may simply be part of the coffee.

No amount of grinder adjustment is going to turn a very dark roast into a light, fruity Ethiopian coffee.

💦 My espresso tastes weak or watery

Weak espresso is slightly more complicated because strength and extraction aren't exactly the same thing.

But I'd start with the basics.

Check how much coffee you're putting into the basket and how much espresso you're getting out.

If you're putting 18g in and getting 70g out, you're making something very different from a traditional espresso.

Try reducing the yield.

Also check the age of the coffee, your grind and your puck preparation.

If water finds an easy route through part of the coffee puck—what we call channeling—you can end up with an espresso that manages to taste weak, sour and bitter at the same time.

Quite an achievement.

🏎️ My espresso runs too fast

Let's say you're using:

18g coffee

and you get:

40g espresso in 15 seconds.

Start by grinding finer.

Your coffee isn't creating enough resistance, so the water is rushing through.

Don't immediately start changing your dose, temperature and everything else.

Grind a little finer and try again.

As a rough starting point, something around 25–30 seconds can be useful.

But remember: time is a diagnostic tool, not the goal.

If your espresso tastes fantastic at 23 seconds, please don't ruin it just to make your stopwatch happy.

🐌 My espresso runs incredibly slowly

If your machine is struggling and you're getting a few miserable drops of espresso after 40 or 50 seconds, you've probably gone too far in the other direction.

Start by grinding coarser.

Again, make a small adjustment.

Espresso grinders can be sensitive. Moving several steps at once can take you from no espresso at all to something resembling coffee-flavoured tap water.

Your coffee might actually be too fresh

This surprises people.

We spend so much time telling everyone that coffee should be fresh that it's easy to assume coffee tastes best five minutes after it leaves the roaster.

Not necessarily.

Freshly roasted coffee releases CO₂, and very fresh coffee can behave unpredictably when you're trying to make espresso.

At Al-Gharb, we generally allow our espresso coffees to rest for at least 10 days after roasting before using them in the café.

Different coffees and roast styles behave differently, so there isn't one magical number.

But if you're struggling to dial in a bag roasted yesterday, the solution might simply be:

Wait.

For once, fixing your espresso requires doing absolutely nothing.