All coffee guides · Troubleshooting
Sharp, lemony or vinegary espresso can indicate under-extraction: too little has dissolved from the grounds. Check flow, grind and yield before adjusting the next shot, and distinguish unpleasant sourness from the coffee’s natural fruit acidity.
Insufficient or uneven extraction can leave a shot tasting sharp and unbalanced. The coffee’s roast, processing and natural acidity also matter. Compounds do not dissolve in a neat sequence of acids, sweetness and bitterness, and taste alone cannot give an exact extraction percentage.
Weigh the dose and espresso yield. Use a dose that suits the basket and note when you start timing; pump start and first drip are different references. Do not diagnose a shot from a universal time cutoff. Check preparation if the flow is erratic.
For a sour shot with otherwise reasonable flow, try a little more yield at the same dose and grind. If flow is unusually fast, try a small adjustment finer while keeping the target yield steady. Compare one change at a time. If needed, explore temperature within the machine’s permitted range after stabilising the recipe.
A bright cup can still be balanced by sweetness and body. A sharp or vinegary taste is not proof of one brewing fault; some coffees may simply be more acidic than you enjoy. Compare another coffee or roast if repeated, careful adjustments do not give the result you want.
Record dose, yield, time and the one change you made, alongside how the cup tasted after cooling slightly. Repeat the better result before making another adjustment. A small measured comparison is more useful than changing dose, grind and temperature together.
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