Crema is the tan foam that sits on a fresh espresso. It is an emulsion: carbon dioxide trapped in the beans during roasting, forced into solution by nine bars of pressure, coming back out as thousands of tiny bubbles wrapped in coffee oils and dissolved solids.
What it actually tells you
Mostly it tells you the coffee is fresh. Beans release CO2 for weeks after roasting, so a coffee two weeks off roast produces generous crema and the same coffee four months later produces almost none. That is the single strongest signal crema gives.
It also reflects the bean and the roast:
- Robusta produces noticeably more crema than arabica, which is why cheap supermarket blends can look spectacular in the cup and taste harsh. Crema volume is not quality.
- Darker roasts produce more, because more gas is developed in the roast.
- Light roasts and natural processed coffees can pull beautifully and still look thin.
Reading a bad-looking shot
Pale, thin, disappears in seconds. Usually stale beans. If the coffee is fresh, the grind is too coarse and the shot ran too fast, so check the timing.
Very dark, thin, with a hole forming in the middle. Over extraction, which normally means too fine a grind or too long a shot. It will taste bitter to match.
Large, soapy bubbles rather than a fine foam. Often channelling: water found a path through the puck instead of saturating it evenly. Distribute and tamp more carefully before blaming the beans.
Pale with dark flecks, sometimes called tiger striping. That is a good sign, usually an even extraction on a fresh coffee.
What crema tastes like
On its own, bitter. That is worth knowing, because a drink built badly can end up with the crema sitting untouched on top and the first mouthful tasting far harsher than the coffee actually is. Stir an espresso before drinking it, and pour milk through the crema rather than on top of it.
Do not chase it
Crema is a by-product, not a goal. A light roast single origin that tastes exceptional may carry a modest crema, and adding robusta or a darker roast to thicken it will cost you flavour. Judge the shot by the taste and the shot time, and use crema as one clue about freshness among several.
Freshness is the part you control at purchase. We grind to your brew method on the day we dispatch rather than selling coffee ground weeks earlier. More on that in how long coffee beans last and how to store coffee beans.
