Fix My Cup

Coffee tastes wrong? Answer a few quick questions and get a diagnosis, with fixes in the order to try them.

Question 1

What's wrong with your cup?

Pick the closest match - take another sip if you need to.

Which way to turn

Under-extracted

Grind finer, brew hotter or longer.

Sweet spot

Leave it alone and enjoy it.

Over-extracted

Grind coarser, brew cooler or shorter.

Weigh everything, change one variable at a time, and remember no technique rescues stale beans or bad water.

How it works

When coffee tastes wrong, the fix depends on the symptom: sour and bitter have opposite causes, and weak has two different ones. This troubleshooter walks you through the same questions a barista would ask and returns a diagnosis with fixes in the order worth trying.

  • Diagnose sour, bitter, weak, muddy, flat, and off-tasting coffee.
  • Get method-specific fixes for espresso, pour-over, and immersion.
  • Learn which single variable to change first - and which to leave alone.

  1. Pick the closest symptom

    Taste the cup and choose what is wrong: sour, bitter, weak, too strong, flat, or a strange off-flavor.

  2. Answer the follow-up questions

    A couple of quick questions about your brew method, timing, roast, or gear narrow the cause down.

  3. Apply the fixes in order

    Each diagnosis lists its fixes by impact. Change one variable, brew again, and re-taste before touching the next.

Questions

Why does my coffee taste sour?

Sourness almost always means under-extraction: the water left before dissolving enough of the coffee. Grinding finer, using hotter water, or extending contact time are the standard fixes.

Why does my coffee taste bitter?

Bitterness usually means over-extraction from a grind that is too fine, water that is too hot for the roast, or contact that ran too long. On espresso machines, rancid coffee oils from infrequent cleaning are another common cause.

My coffee is weak - should I grind finer?

Only if it is also sour. If the cup tastes balanced but thin, the problem is the ratio, and the fix is more coffee, not a finer grind. Grinding finer to fix balanced-but-weak coffee trades thin for bitter.

What should I change first when dialing in?

One variable at a time, starting with the one the diagnosis ranks first - usually grind size. Changing two things at once means you cannot tell which one worked, so every fix in this tool is meant to be tested with a single brew before moving on.