How to Fix Sour or Bitter Coffee: 5 Simple Adjustments

• Grind finer. A finer grind increases surface area, allowing water to extract more flavour in the same time.

• Brew longer. If you're using a pour-over, slow down your pour. If you're using an espresso machine, aim for a slightly longer shot (e.g., 30 seconds instead of 25).

• Use hotter water. Water around 90–96°C extracts more efficiently than cooler water.

Quick test: Brew the same coffee with a finer grind and taste the difference within one cup.

2. Bitter Coffee? Your Grind Might Be Too Fine

Bitter, harsh, or burnt-tasting coffee is the opposite problem—over-extraction. The water has pulled too many compounds from the grounds, including undesirable bitter ones.

How to fix it:

• Grind coarser. A coarser grind slows extraction, reducing bitterness.

• Shorten brew time. For espresso, aim for 25–27 seconds. For pour-over, increase your pour speed.

• Use slightly cooler water. Try 88–92°C instead of boiling water.

Pro tip: If your espresso machine pulls shots too fast (under 20 seconds), your grind is too coarse. If shots run too slow (over 35 seconds), your grind is too fine.

3. Check Your Water Quality

Hard water or chlorinated tap water can mask the true flavour of specialty coffee and contribute to bitter or off-tasting cups.

How to fix it:

• Use filtered water. A simple jug filter removes chlorine and sediment.

• Consider bottled water. If you're serious about dialling in, use bottled water to isolate variables.

• Avoid distilled water. Paradoxically, water that's too pure doesn't extract coffee well.

For Australian homes, tap water quality varies by region. If you're in Melbourne, filtered water is usually sufficient.

4. Dial In Your Coffee-to-Water Ratio

The ratio of coffee to water affects both extraction and strength. Too much water can lead to weak, sour coffee; too little can create over-extracted bitterness.

Standard ratios:

• Espresso: 1:2 (e.g., 18g coffee to 36g liquid)

• Pour-over: 1:16 (e.g., 20g coffee to 320g water)

• French press: 1:15 (e.g., 30g coffee to 450g water)

How to adjust:

• If your coffee tastes weak or sour, use slightly more coffee.

• If it tastes bitter, try using slightly less coffee and more water.

5. Freshness Matters—Use Coffee Within 4 to 24 Weeks of Roasting

Stale coffee (older than 24 weeks from roast date) is harder to extract properly and often tastes flat, sour, or dull.

How to fix it:

• Check the roast date. Look for it on the bag—it should be recent.

• Store correctly. Keep beans in an airtight container, away from light and heat.

• Buy smaller quantities. Purchase only what you'll use in 3–4 weeks.

At Ariga Coffee, all our single-origin and blend coffees are roasted fresh in Melbourne. Check the roast date on your bag and brew within 4 weeks for the best flavour.

Conclusion

Sour or bitter coffee is almost always a brewing issue, not a bean issue. Start by adjusting one variable at a time—grind size, brew time, or water temperature—and taste the difference. Most home brewers find that dialling in their grind size solves 80% of flavour problems.

If you're using fresh, quality coffee and still struggling, it might be time to explore a different brewing method or invest in a burr grinder for more consistent results. Explore our  Single Origin collection and experiment until you find your perfect cup.