Caffeine.supply

Coffee Taste Troubleshooter

Tell us what your cup tastes like. We show the likely cause and the fixes in the order to try them. Change one thing per brew.

Sour or sharp coffee: under-extraction

The water pulled the fast-dissolving acids but quit before the sugars. The cup tastes sour, thin and sometimes salty.

  1. Grind finer. The biggest lever. Go one or two steps finer to slow the water and raise extraction.
  2. Use hotter water. Brew at 94 to 96 °C (200 to 205 °F). Water below about 90 °C under-extracts, especially with light roasts.
  3. Brew longer. Add 20 to 30 seconds of contact time, or let a French press steep a minute more.
  4. Check the roast. Light roasts need finer grinds and hotter water than medium or dark roasts. A very light roast may simply need more extraction than your recipe gives.

Frequently Asked Questions

Why does my coffee taste sour?
Sour coffee is almost always under-extracted: the water dissolved the acids but not the sugars. Grind finer, raise the water temperature to 94 to 96 °C, or brew a little longer. Change one thing at a time.
Why does my coffee taste bitter?
Bitterness usually means over-extraction. Grind coarser, lower the water temperature to 90 to 93 °C, or shorten the brew. If you drink dark roast, some bitterness is part of the beans themselves.
How do I tell sour from bitter?
Sour is bright, sharp and lingers on the sides of the tongue, like unripe fruit. Bitter is heavy, drying and sits at the back of the tongue, like burnt toast. If you taste both, the extraction is uneven. See the harsh and astringent fix.
Should I change grind size or brew time first?
Change grind size first. It has the largest and most predictable effect on extraction. Then adjust temperature, then time. Alter one variable per brew so you know what worked.
Can the beans themselves be the problem?
Yes. Stale beans taste flat no matter how you brew, and very light roasts can taste sour unless brewed hot and fine. Browse our 619 specialty coffees from 100 roasters to find a roast level and origin that suits your taste.

Related Tools and Guides

Grind Size Guide → Extraction Calculator → Water Temperature Guide → Brew Ratio Calculator → Why Does My Coffee Taste Bad? → Find Better Beans →