(Please excuse the digression / talking down, if this is familiar territory).

In biomedical research, quite often a ’surrogate’ marker, or endpoint, is used/measured, rather than the thing we’re really interested in. This may be for several reasons – it may be easier to measure, cheaper to do so, or it may produce results faster than waiting for the real endpoint of interest. (Drug companies often like this type of study, as it shows up promising data sooner).

A good example would be much of the research into drug treatments for HIV/AIDS. In this case, the real endpoint, (the index we’re interested in), is usually mortality, deaths. But it can take a long time, decades, to collect that sort of data. So instead, we can measure another index, in this case the number of CD4 T cells, in the patient’s blood. We do this before and after the treatment, and look for an improvement. Then, we hope that an improvement in this index will correlate with an improvement in the real index, the one we care about. Often, only time will tell, though we can suggest mechanisms why there might be a correlation in advance.

Crema on espresso may be like this – it correlates with fresh beans, clean equipment, reasonable skills at the machine – but it doesn’t tell us what the cup will taste like. Confounding factors, like the extreme of ‘perfect crema’ devices, make it an imperfect index.

So when we have access to the real index (when we can taste the coffee), we shouldn’t care about the surrogate. Perhaps crema has its place, for instance in telediagnostics and internet forums where tasting the espresso is impossible – and I’m also quite attached to it – but perhaps its importance has been taken way out of proportion.

Muchas Gracias

Oddly enough, i didn’t like either option.

My shots are pulled straight into a heated cup timed at 25-30 seconds for subsequent latte.

To me the taste was much better then skimming. I tried 5 different beans and roast variations.

All of which tasted better without skimming.

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I have tried this during the week, and I really feel like this benefits cappuccinos more than a straight shot of espresso. In the past I have always tried to “aim” for the spot in the cup where there is no crema on top. When skimming off the crema, it creates a uniformily sweet and creamy cap. I tried it with some customers and they all agreed that the capps were smoother.

I do have to say that I miss the mouthfeel in a straight shot though…

The information offered by crema really is relatively limited, and I think it is something we worry way too much about.

I think if people take the time to occasionally re-asses their coffee then that is enough.

This reminds me of the first time I met Heather Perry. At the USBC 2008 in Minneapolis a few of us were having a discussion about the rules of the competition. Heather stated that she knew her espresso did not have good crema but she would gladly sacrifice the visual points in order to get the flavor points that were more important. hmm. I don’t think at the time she was necessarily saying “crema is bad, ew” but she knew her espresso and she knew what factors made it taste good or bad regardless of what some rules said an espresso must be in order to taste good. This blew my mind at the time. In a competition setting the winners are the ones who understand the rules enough to know which ones to follow and which ones need to be broken. In real life, understanding the rules is about being able to communicate with our customers and being able to give them something they each can enjoy. This is why I love coffee, it makes us think too much.