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Why your espresso tastes sour or bitter
Updated
Sour, thin espresso usually means the water went through too fast, so grind finer. Bitter, harsh espresso usually means the water was held back too long, so grind coarser. Check it with numbers: 18 grams of coffee in, about 36 grams of espresso out, in 25 to 30 seconds. If your shot is far outside that, fix the time first and judge the taste after.
Sour
- Shot ran fast (well under 25 seconds for 36 grams). Grind finer. This is the cause most of the time.
- Dose too low. Weigh it. A light basket lets water race through.
- Machine not warm. Run a blank shot through the empty handle first to heat the handle and the cup.
- Very light roast. Light roasts are harder to extract. Beans sold as an espresso roast are easier to start with.
Bitter
- Shot ran slow (well over 30 seconds). Grind coarser.
- Too much coffee out. If you let the shot run past 36 grams, the last part is thin and bitter. Stop it on time.
- Old oils in the machine. A dirty basket and group head add a burnt, stale taste. Clean them on the manual's schedule.
- Very dark or stale beans. Some bitterness comes with the roast and no grind setting removes it.
Sour and bitter at once
This is usually channeling. Water found a weak spot in the puck and rushed through it, so part of the coffee gave up too much and the rest too little. Break up clumps, level the grounds and tamp flat. It is also what too much pressure does, which is one reason 20 bar is not better than 9 bar.
If you cannot change the grind
With pre-ground coffee you have few levers. Use the pressurized basket, keep the dose steady, and stop the shot earlier if it tastes bitter. That is the ceiling we describe in do you need a grinder. The CASABREWS CM5418 and De'Longhi Stilosa are listed for ground coffee, so owners of those two will run into this first.
Machines and grinders that make this easier
- Breville Barista Express: the grinder dial and the pressure gauge sit on the same machine, so you can see a change right away. Caveat: there is a learning curve.
- Baratza Encore ESP: owners say it is easy to dial in. Caveat: owners also report a mess of grounds on the counter.
For the full routine, see how to dial in espresso.
Sources
We opened these pages on September 18, 2026.