Everyone loves crema in a coffee. But how does it form?
Beautiful crema. For a long, long time the appearance and quality of crema were the defining characteristics with which the quality of an espresso was judged.
Traditionally, the perfect crema is a deep, reddish hazelnut colour that will hold a teaspoon of sugar for several seconds.
The crema, however, is really just a by-product of brewing under pressure and the effect this has on the CO2 in the coffee. It cannot tell you the quality of the coffee, but will instead indicate the freshness of the coffee (coffee loses CO2 and therefore crema as it ages) and the darkness of the roast (a darker roast will produce a darker crema).
As such, the highest-scoring coffees do not necessarily produce the highest-scoring cremas. I adore the crema in my coffee? What about you?