Why Does My Coffee Taste Bitter? (And How to Fix It)

We’ve all been there: you brew a fresh cup of coffee or pull an espresso shot, take that first hopeful sip… and it hits you with a harsh, lingering bitterness. As a roastery, we hear this question often, and the good news is that bitterness is almost always fixable with a few simple tweaks.

Below are the most common reasons your espresso, V60, or AeroPress might taste bitter — along with easy remedies to help you brew sweeter, cleaner, more balanced coffee at home.

1. You’re Extracting Too Much Coffee (Over-Extraction)

What it tastes like: bitter, dry, astringent, “burnt” or hollow.

When water spends too long pulling flavours out of coffee, it starts extracting the harsh compounds that sit deeper in the grounds. This is the number-one culprit for bitterness in both espresso and filter brews.

Fix it:

• Espresso: Try a coarser grind and slightly shorten your shot time. Aim for about 1:2 ratio in 25–30 seconds on most home machines.

• V60: Coarsen the grind or speed up your pour so the brew finishes in 2:30–3:00 minutes.

• AeroPress: Shorten the brew to 60–90 seconds or switch to a coarser grind.

If you’re using our beans, check the label or product page — we include suggested brew ratios to help you get in the sweet spot.

2. Your Water Temperature Is Too High

What it tastes like: sharp bitterness, “scalded” flavour.

Water that’s too hot extracts harsh compounds faster than you want.

Fix it:

Aim for 92–96°C for both espresso and filter.

No kettle thermometer? Let freshly boiled water rest for 15–25 seconds before brewing.

Many home espresso machines run a bit hot — if yours does, consider a slightly coarser grind or shorter extraction.

3. Your Coffee Is Stale or Over-Roasted

What it tastes like: dull bitterness, ashy notes, smoky harshness.

Old coffee naturally breaks down and becomes more bitter. A darker roast also leans more toward smoky, roasty flavours, which some enjoy — but if you’re tasting unpleasant bitterness, freshness and roast style matter.

Fix it:

Use beans within 3 - 6 weeks of the roast date for the best flavour.

If you prefer milder cups, choose our light-to-medium roasts, which are designed for clarity and sweetness in both espresso and filter.

Store your beans in an airtight container away from heat and light.

4. The Grind Size Isn’t Dialled In

What it tastes like: bitterness combined with muddiness or heaviness.

A grind that’s too fine slows down water flow, causing over-extraction.

Fix it:

Espresso grinders drift over time — adjust coarser in tiny steps.

Pour-overs benefit from uniform grind quality; a good burr grinder makes a huge difference.

If you’re having trouble, email us or bring your brewer and grinder into the roastery - we’re happy to help you dial it in.

Did you know we also service Sage and De'Longhi espresso machines? Send us your machine to be fixed and you'll also get free coffee too!

5. Your Coffee-to-Water Ratio Is Off

What it tastes like: strong bitterness, heaviness, or “syrupy” harshness.

If you use too much coffee, you may overwhelm the cup and draw out more bitter compounds.

Fix it:

• Espresso: Start with 18 g in → 36 g out.

• V60: Use a 1:16 ratio (e.g., 15 g coffee → 240 g water).

• AeroPress: Try 14–16 g coffee for 200–220 g water.

Using a scale is one of the quickest ways to improve your coffee instantly.

6. Your Water Quality Might Be the Issue

What it tastes like: chalky bitterness, strange aftertaste.

Hard water extracts differently and can mute sweetness or exaggerate bitterness.

Fix it:

If local tap water tastes “off,” try filtered or bottled water with moderate mineral content. Your coffee (and espresso machine) will thank you.

Final Thoughts

Bitterness isn’t a flaw in coffee - it’s part of its complexity. But when it dominates the cup, it usually means something in the brewing process needs a gentle nudge. With fresh beans, good water, and a few adjustments to grind size and brew time, you can transform that bitter cup into something beautifully balanced.

If you ever need help dialling in your espresso, V60, or AeroPress, feel free to drop us a line at hello@cuckfieldcoffee.co.uk we love helping customers brew better at home.