If your coffee doesn’t taste quite right, there’s usually a simple reason behind it. Coffee is sensitive so small changes can have a big impact on flavour. The good news? Once you know what to look for, it’s easy to fix.

Let’s break down the most common espresso issues, what causes them, and how to get your coffee tasting balanced and smooth again.

​​When espresso tastes sharp, sour or watery

If your espresso tastes thin, sour or lacks body, it’s likely under-extracted.

This happens when water passes through the coffee too quickly, not pulling enough sweetness, oils or depth from the grounds. The shot usually runs fast, looks pale and produces little crema, leaving you with a cup that feels hollow and sharp.

Think of it like making soup without letting it simmer long enough. The ingredients are there, but the flavour hasn’t had time to develop.

How to fix it

Start by slowing the extraction so the water has more time to do its job:

• Grind slightly finer to increase resistance and slow the flow
• Make small adjustments rather than big jumps
• Aim for a steady, controlled pour rather than a fast gush

This gives the water more contact time with the coffee, allowing sugars and oils to be properly extracted.

How you’ll know it’s fixed

You should notice:

• A slower, more even shot that starts dark and lightens gradually
• Thicker, more consistent crema
• A fuller mouthfeel with more sweetness and balance
• Less sharp acidity and more rounded flavour overall

When espresso tastes bitter, dry or harsh

On the other end of the scale, bitter or drying espresso is usually over-extracted.

This happens when water spends too long in contact with the coffee. The shot often runs very slowly, looks dark and heavy, and pulls out harsh, drying compounds along with the good flavours.

It’s like leaving a marshmallow on the fire just a little too long – it goes from golden to burnt very quickly.

How to fix it

The goal here is to speed things up slightly:

• Grind coarser to reduce resistance
• Watch for a smoother, more relaxed flow

A slightly faster extraction helps highlight sweetness and clarity rather than bitterness.

How you’ll know it’s fixed

You should see and taste:

• A shot that flows evenly without stalling
• Crema that’s present but not thick or muddy
• A smoother flavour with less dryness on the finish
• Bitterness that feels supportive rather than overpowering

When your espresso is dialled in

When your grind is right, espresso should taste smooth, balanced and full. The pour will be steady, the crema consistent, and the flavour will feel rounded rather than sharp or harsh. If it tastes good and feels good to drink, you’re on the right track.

Other common mistakes that can throw your coffee off

Even with the right grind, a few everyday habits can affect your espresso more than you might realise.

1. Not using filtered water

This one we are passionate about! Water makes up most of your coffee. Poor-quality or heavily chlorinated water can mute sweetness, flatten acidity or add unwanted bitterness. Filtered water helps flavours shine and keeps your machine healthier too.

2. Not cleaning your equipment

Old coffee oils build up quickly and turn rancid, even if you can’t see them. This often shows up as dull, bitter or stale flavours in the cup. Regular cleaning keeps your espresso tasting clean and consistent. We have a helpful video here on tips for cleaning your machine.

3. Uneven or inconsistent tamping

If the coffee bed isn’t level and firm, water will find the easiest path through the puck. This leads to uneven extraction, where parts of the coffee are over-extracted and others under-extracted, creating a muddled or unbalanced shot.

4. Leaving coffee in the portafilter

Coffee left sitting in the basket after a shot continues to oxidise and can affect the flavour of the next extraction. Always knock out the puck and give the basket a quick wipe before pulling another shot.

5. Using old coffee beans

Freshness matters. As coffee ages, it loses sweetness, aroma and complexity, no matter how well it’s brewed. Always check the roast date and store beans in an airtight container, away from heat and light.

6. Not preheating your machine

Espresso is sensitive to temperature. Turn your machine on at least 15-20 minutes before brewing and run a blank shot through the group head and portafilter. Proper heat stability helps ensure consistent extraction and better flavour.

7. Use milk in your brew? This can make or break your coffee

Overheating milk kills sweetness and can make coffee taste dry or bitter, especially with alternative milks. Aim for 60–65°C for dairy and slightly cooler (50–60°C) for plant-based milks so the coffee stays balanced.

8. Changing too many variables at once

When something tastes off, it’s tempting to adjust everything at once. This makes it hard to know what actually fixed the problem. Change one thing at a time and taste as you go.

Small adjustments, better coffee

Great espresso isn’t about complicated techniques, it’s about understanding cause and effect. By paying attention to grind size, freshness, water and cleanliness, you’ll get more consistency and better flavour in every cup.

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