Every disappointing shot leaves clues. It tastes sour, or bitter, or somehow both at once. It gushes out in ten seconds, spits sideways, or crawls into the cup like treacle. The good news: espresso only goes wrong in a handful of ways, and each one points to a fix.
Find what you’re tasting or seeing in the left column, make the first fix, then pull another shot. Change one thing at a time so you know which change did the work. Every row links to a full guide when you want the why as well as the what.
Espresso: symptom, cause, fix
| You taste or see | Likely cause | First fix | Full guide |
|---|---|---|---|
| Sour, sharp or thin, and the shot runs fast | Under-extraction | Grind finer, in small steps | Espresso dial-in guide |
| Bitter, harsh or drying, and the shot runs slow | Over-extraction | Grind coarser | Espresso dial-in guide |
| Sour, but the time looks right | Yield too short | Let it run a few grams longer | Espresso dial-in guide |
| Bitter, but the time looks right | Yield too long, or a very dark roast | Stop a few grams earlier | Espresso dial-in guide |
| Watery or weak, but the flavour is fine | Strength too low | Shorter yield, or dose up 0.5–1 g | Espresso dial-in guide |
| Sour and bitter in the same sip | Uneven extraction (channeling) | Fix your puck prep before you touch the grinder | Espresso channeling |
| Gushes, spurts or sprays sideways from a bottomless portafilter | Channeling | Break up clumps, distribute evenly, tamp level, and don’t tap after tamping | Espresso channeling |
| Grinding finer barely changes anything | A pressurized (dual-wall) basket | Adjust dose, freshness and shot volume, or switch to a single-wall basket with fresh-ground coffee | Pressurized vs non-pressurized baskets |
These are starting points, not laws. Your tongue gets the final vote.
Milk misbehaving?
| You taste or see | Likely cause | First fix | Full guide |
|---|---|---|---|
| Big bubbles, soapy foam | Air added too late, or the tip sat too high for too long | Stretch earlier and more briefly, then submerge the tip sooner | Milk steaming and latte art |
| A thick, dry cap that won’t pour | Too much air, or milk left to sit | Add less air, swirl continuously and pour sooner | Milk steaming and latte art |
| No white shape appears when you pour | Spout too high during the draw, or flow too slow | Bring the spout almost onto the surface and pour a little faster | Latte art for beginners |
The one rule that fixes most shots
Lock your dose. Change one variable per shot, grind first and then yield, and write down what you did. It feels slower than twiddling three dials at once. It isn’t. Three changes at once just means three suspects and no confession.
Writing it down is easier with the right sheet. Our free Espresso Dial-In Chart & Shot Log puts the taste-to-fix table and a 14-shot log on two printable pages.
Fix it for good, free: our short video course Dial In Espresso by Taste teaches the whole taste-first loop in about an hour of short lessons, with quizzes and a printable shot log. Learn to name what’s wrong in one word, then fix it.
We add new fixes to this page as they go live. If your symptom isn’t here yet, check back soon.