Crema!

Coffee foam explained

This week is a strange one as it can be quite polarising on the topic of crema.

Crema is the smooth foamy top to every good espresso but it’s not quite what people think. In around the 1950s, espresso was revolutionised with a new machine by Achille Gaggia, this new espresso machine was capable of producing much higher pressure than all other machines around.

Due to the high pressure used, the coffees where extracting with a foam on top which was seen as an undesirable scum on the drink, Achille marketed this change from the norm as a positive saying it was “natural coffee cream” with cream in Italian being crema. The popularity of this marketing became the new normal for espresso and has stayed as a standard for all espressos to this day!

Where does it come from?

Crema is just CO2 that creates a foam on the espresso but the CO2 itself comes from the roasting process of the coffee. CO2 is a biproduct of the Millard reaction when coffee beans are roasted, the CO2 is then trapped in the beans slowing being released over a long period of time (this is called “degassing").

Crema is just CO2 foam of the espresso similar to that of a head of foam on a pint.

When ground coffee is exposed to high pressure water in espresso extractions, the water dissolves the CO2 into the liquid espresso and as it pours into the cup the pressure is released and the CO2 forms as bubbles on the surface.

Is crema good?

As mentioned before, crema has become a good indicator for a successful espresso extraction as long as the time to extract is within your recipe time range.

Although you want to see crema on all the shots you extract and its by far the best looking part, don’t let appearances deceive you as just like all foams of drinks, it’s not very tasty.

A fun thing to try for this week is to using a spoon, scoop off the crema from your espresso or americano/long black and try your drink without the crema, see if you notice any difference as what you can expect is a less bitter flavour overall. In addition to trying the drink without crema, feel free to try some of the crema you’ve scooped off and you’ll see what I mean when I said it’s not very tasty.

I hope you’ve enjoyed this week and give the crema removal a go! have a great week and some even better coffees.