Why is there no crema on my espresso?

Crema is a foam of carbon dioxide, coffee oils and water, formed when nine bars of pressure force dissolved gas out of solution. It tells you two things: that the coffee still holds CO₂, and that the machine built real pressure.

Stale beans is the cause most of the time. Coffee releases CO₂ steadily from the moment it is roasted, and by two or three months there is little left to emulsify. A bag with a best-before date and no roast date is usually well past this.

The other side of that: beans roasted within the last few days can produce huge, pale, unstable crema that collapses quickly, because there is too much gas. Coffee is generally best from about five days to five weeks after roasting.

Pre-ground coffee has the same problem, faster. Most of the CO₂ escapes within hours of grinding.

A machine not reaching pressure produces no crema regardless of the coffee. If the shot also gushes, the coffee bed is not resisting — grind finer. If the pump strains and little comes out, something is blocked.

Crema is not a quality measure

This deserves saying plainly, because a lot of marketing depends on the opposite. Robusta produces far more crema than arabica while generally tasting worse. Pressurised baskets manufacture crema from any coffee at any grind by forcing water through a valve. Dark, oily roasts crema readily.

So thick crema does not mean good coffee. It means gas and pressure. Judge the shot by taste; use crema only as a rough signal that your beans are fresh and your machine is working.

What to check first

Find the roast date on the bag. If there isn’t one, that is very likely your answer.