Espresso guide
Why your espresso tastes sour
A sour, sharp or thin shot is the most common problem home baristas hit — and it almost always means the same thing: under-extraction. The water didn't pull enough out of the coffee.
How to tell it's under-extracted
Taste is the clearest signal. Under-extracted espresso is:
- Sour or sharply acidic — like underripe fruit, not pleasant brightness
- Thin and watery, with little body or sweetness
- Quick to fade — the flavour disappears instead of lingering
Your shot often confirms it before you taste it: a fast flow (under 20 seconds for a typical 1:2 ratio), pale crema, and a light, quick blonding of the stream.
The one change to make next
Grind slightly finer. A finer grind slows the water down and gives it more contact with the coffee, which extracts more sweetness and body to balance the sourness.
Keep everything else exactly the same — same dose, same yield, same beans. Change one thing, taste the result, and you'll know precisely what the grind adjustment did.
If it's still sour
Go a little finer again, or extend the yield slightly (for example from 36g to 38g out of an 18g dose). Fresh beans matter too: coffee that's very fresh (under a week off roast) can taste sharp regardless of your recipe, and stale coffee never sweetens up.
Avoid the temptation to change grind, dose and temperature all at once — when the shot improves, you won't know which change fixed it.