Factors that impact crema?

wilburpan

My wife and I came back from a quick trip this weekend. During the 8-hour drive back, we stopped off to get some double espressos for a break and the caffeine. The espresso wasn’t that great. It felt like it was over-extracted and bitter, but the thing that stuck with me was the lack of crema and the rich mouth feel compared to what I can make at home.

My question is, what factors impact how much crema in a shot of espresso?

MediumRoastSteam

wilburpan what factors impact how much crema in a shot of espresso?

My understanding is that crema (referred to in the context of an espresso extraction, rather than he literal meaning of one of the Italian words for “cream”) is a mixture of carbon dioxide and coffee oils. The fresher the coffee, the more crema it will have.

The likelihood is that, essentially, you had coffee that’s not as fresh as what you were expecting.

Also, some coffees have more crema than others. I find that, for instance, an Ethiopian lightly roasted coffee will produce a lot less crema than something roaster darker, or which has robusta in it.

Crema, in itself, is very bitter and not pleasant.

Cuprajake

Old beans

Platypus

I find lighter roasts produce less Crema than dark and conical burrs tend to give more of a gloopy shot than large flats.
Turbos are thinner shots producing very little crema at all but highlight fruit/florals in lighter roasts, often used in “Scandi modern” coffee bars.

coffeealex

I think rightly as some have already pointed out, fresh beans makes a massive difference but also the variety of beans can make a difference. Even if you have the best mix of beans, but they are stale, you will end up with thin, black coffee and little or no crema

Systemic

Crema is CO2 and emulsified oils from the bean. If it has striping in it, that’s fines suspended in the foam. Older beans will have less CO2 in them so the crema will be thinner. As for lighter roasts producing less crema, not so sure about that.

CoyoteOldMan

Possibly included under “variety of beans” above, but whether the mix includes Robusta (and how much) or it’s only Arabica. Robusta produces much more CO₂, thus more crema.

wilburpan

So the consensus seems to be the beans, mainly freshness. Makes sense, as the place we were at sold coffee beans, but I didn’t see a roast date or expiration date on the bags at all.

There weren’t any mention of factors that you would normally adjust when making espresso, like grind and dose, so it seems that the crema is relatively independent of that. That seems to match my experience with what I make at home. The only time that my technique really seems to affect the crema is in outlier situations. For example, if the grind is too coarse to the point where the extraction is way too short, like 15 seconds, the crema doesn’t seem to develop. But that shot of espresso is going down the sink for many other reasons, anyway. 😉

coffeealex

wilburpan but I didn’t see a roast date or expiration date on the bags at all.

Generally speaking if you cant see or know the roast date they are likely not to be fresh. Expiration date is practically meaningless. Anyone selling fresh beans will be able to tell you when they were roasted. That’s why on the whole beans from supermarkets are hit and miss