Espresso Troubleshooting

A bad espresso usually isn’t far away from a good one.

If your coffee tastes sour, sharp, bitter, dry or hollow, the problem is often extraction.

The useful part is that flavour can tell you which direction to move.

Instead of changing everything at once, learn what the espresso is telling you and make one small adjustment at a time.

SOUR VS BITTER: WHAT’S THE DIFFERENCE?

Sour and bitter can sometimes be confused, especially when you're still learning to taste espresso.

Sour espresso often tastes sharp, acidic, thin or underdeveloped.

Think of an unpleasant lemon-like sharpness rather than the balanced acidity you might find naturally in coffee.

Bitter espresso tends to taste dry, harsh, heavy or burnt.

The flavour can linger unpleasantly and sometimes leave your mouth feeling dry.

Neither one automatically means the coffee itself is bad.

Often, it simply means the extraction needs adjusting.

WHY DOES ESPRESSO TASTE SOUR?

Sour espresso is commonly associated with under-extraction.

Under-extraction means the water hasn't dissolved enough from the coffee.

The shot may taste:

• Sharp
• Sour
• Thin
• Salty
• Hollow
• Underdeveloped

One of the first things to look at is your grind.

IF YOUR SHOT IS RUNNING TOO FAST

If you're reaching your target yield much faster than expected, water may be passing through the coffee too easily.

Try grinding finer.

A finer grind creates more resistance and generally slows the shot down, giving the water more opportunity to extract flavour from the coffee.

Make a small adjustment, keep your dose and yield the same, and try again.

WHY DOES ESPRESSO TASTE BITTER?

Bitter espresso can be associated with over-extraction.

This means the water has extracted more from the coffee than you wanted.

The shot might taste:

• Bitter
• Dry
• Harsh
• Astringent
• Heavy
• Burnt

IF YOUR SHOT IS RUNNING TOO SLOW

If your espresso takes a long time to reach your target yield or is barely dripping from the portafilter, your grind may be too fine.

Try grinding coarser.

A coarser grind creates less resistance and allows water to pass through the coffee more easily.

Again, make a small adjustment rather than making a huge change.

GRIND SIZE IS YOUR MAIN ADJUSTMENT

When dialling in espresso, grind size is usually the easiest variable to change.

If the shot is:

Too fast and sour → grind finer.

Too slow and bitter → grind coarser.

Keep everything else as consistent as possible while making the adjustment.

If you change the grind, dose and yield at the same time, it becomes difficult to know which change actually improved the coffee.

SHOT TIME IS A GUIDE, NOT THE GOAL

It's easy to become obsessed with hitting an exact extraction time.

You might have heard that espresso needs to run for exactly 28 seconds, 30 seconds or some other specific number.

Those numbers are useful starting points.

They are not rules.

A shot that tastes great at 26 seconds is better than a shot that tastes terrible at exactly 28 seconds.

Use time to understand what's happening, but let flavour make the final decision.

DOSE AND YIELD MATTER TOO

Grind size isn't the only thing that affects extraction.

Your dose is the amount of dry coffee going into the portafilter.

Your yield is the amount of liquid espresso coming out.

For example:

20g of ground coffee in and 40g of espresso out is a 1:2 brew ratio.

Changing your yield changes how much water passes through the coffee.

More water generally extracts more.

Less water generally extracts less.

That means yield can also be useful when you're fine-tuning flavour.

WHAT IF THE SHOT TIME LOOKS RIGHT BUT THE COFFEE STILL TASTES SOUR?

This is where taste becomes more useful than the timer.

If your shot is running in a sensible range but still tastes sour, you can try extracting slightly more from the coffee.

That might mean:

• Grinding slightly finer
• Increasing your yield slightly
• Checking that your coffee is evenly distributed
• Making sure your dose is appropriate for the basket

Change one thing at a time.

Then taste again.

WHAT IF THE SHOT TIME LOOKS RIGHT BUT THE COFFEE STILL TASTES BITTER?

The same logic applies in the opposite direction.

If the shot time looks reasonable but the coffee tastes dry, harsh or bitter, try reducing extraction slightly.

You could try:

• Grinding slightly coarser
• Reducing the yield
• Checking that your coffee isn't being over-extracted
• Making sure your machine is clean

Small adjustments usually tell you more than large ones.

DON'T IGNORE YOUR ESPRESSO MACHINE

Sometimes the problem isn't your recipe.

Old coffee oils around the group head, basket and portafilter can affect the flavour of fresh espresso.

If your coffee suddenly starts tasting unpleasant even though your recipe hasn't changed, cleanliness is worth checking.

A dirty machine can make dialling in much harder because you're tasting old coffee residue as well as the coffee you're trying to adjust.

Read our Espresso Machine Cleaning Guide if your machine is due for some attention.

FRESH COFFEE CHANGES

Coffee doesn't behave exactly the same way forever.

As roasted coffee ages, it releases carbon dioxide and can extract differently.

Temperature and humidity can also affect your grinder and coffee.

That means the grind setting that worked perfectly a few days ago might need a small adjustment today.

This is normal.

Dialling in isn't something you only do once.

MAKE ONE CHANGE AT A TIME

This is one of the simplest ways to improve your espresso.

If your coffee tastes wrong, resist the temptation to change everything.

Keep your dose consistent.

Keep your target yield consistent.

Adjust your grind.

Taste the result.

Then decide whether another adjustment is needed.

That gives you useful information from every shot.

A SIMPLE ESPRESSO TROUBLESHOOTING GUIDE

SOUR OR SHARP

The espresso may be under-extracted.

Try grinding finer and taste again.

BITTER OR DRY

The espresso may be over-extracted.

Try grinding coarser and taste again.

SHOT RUNNING TOO FAST

Grind finer.

SHOT RUNNING TOO SLOW

Grind coarser.

SHOT TIME LOOKS RIGHT BUT TASTE IS WRONG

Trust the flavour.

Make a small adjustment and taste again rather than chasing an exact number.

TASTE COMES FIRST

Espresso recipes give you a starting point.

They don't tell you exactly what every coffee should taste like on every grinder and every machine.

Use dose, yield and extraction time to understand what's happening.

Then use taste to decide where to go next.

If you're still getting comfortable with dose, yield, grind size and extraction time, start with our Espresso Brew Guide.