You bought the same beans and it is not the same cup. Here is the order in which to suspect things.
1. The grinder
Almost always the answer. A café grinder costs more than most home setups combined and produces a far more uniform particle distribution.
Uniformity is what makes a shot taste clean rather than simultaneously sour and bitter. This is the single biggest gap, and it is why the standard advice is to spend on the grinder first.
2. Freshness
A busy café goes through a kilo a day. Your bag has been open for three weeks.
3. Water
Cafés on soft water, or with a proper filter, are brewing with water in the right mineral range. Your tap water may not be, and it changes the cup substantially.
4. Temperature stability
A commercial machine holds brew temperature within a degree. Many home machines swing by five or more, shot to shot.
5. Skill and volume
A barista makes hundreds of drinks a day on one machine with one coffee. That is a lot of feedback.
6. The milk
Café milk is often whole, cold, and steamed with a powerful boiler that produces microfoam quickly. Domestic steam wands are weaker and the texture is harder to get.
What to do
Weigh in and out, dial deliberately, use filtered water, buy fresh — and if you are going to spend money, spend it on the grinder.
Last reviewed 8 August 2026