Sour espresso is the most common complaint on an espresso machine — and almost never the beans' fault. It is a fixable extraction problem, usually grind, dose or temperature.
This guide walks the three dials that fix sour shots in most machines, in the order to try them.
Grind finer first
Sour usually means under-extraction — the water rushed through too fast. Grind finer (or use a more precise grinder) until the shot runs slower and turns from sour to sweet.
Ration, dose and temperature
If a finer grind is capped by your machine, pull a longer shot (more yield) to balance sourness, or raise the brew temperature a touch — hotter water extracts more.
When it's not the grind
Old beans or a very light roast can taste sour no matter what you do. Track the roast date: beans past 4-6 weeks taste sour on the finest settings. Descale too — scale affects temperature output.
If you've ground fine, dosed correctly and still taste sour, suspect the beans or the water. Both are easy fixes.
