Most bad home espresso has nothing to do with your machine. It comes from a few habits that are easy to fix once you know them. If your shots taste sour, bitter, or just thin, run through this list.

1. Using stale, pre-ground coffee Espresso is unforgiving of old coffee. Buy whole beans, ideally roasted within the last few weeks, and grind right before you brew. Pre-ground coffee loses its best flavors within minutes.

2. Grinding too coarse A coarse grind lets water rush through, producing a sour, watery shot that finishes in well under twenty seconds. Espresso needs a fine, almost powdery grind so water has to push through resistance.

3. Not using enough coffee Eyeballing your dose leads to weak shots. Weigh your coffee with a small scale. A typical double shot uses roughly 18 grams of grounds. Consistency here changes everything.

4. Skipping the tamp An uneven or gentle tamp creates channels where water shoots through, leaving the rest of the puck under-extracted. Tamp level and firm.

5. Ignoring shot time Aim for your double shot to flow in about 25 to 30 seconds. Too fast means grind finer; too slow means grind coarser. Time it.

6. Brewing into a cold cup A cold cup robs heat from a tiny volume of espresso. Pre-warm your cup with hot water.

7. Never cleaning the machine Old coffee oils turn rancid and ruin flavor. Backflush and wipe down regularly.