Water and espresso….A contentious subject didn’t you know?!
Well, the devil is always in the detail isn’t it?
For example – Are you the kind of espresso drinker who enjoys their perfetto moment neat, with no other accompaniment, or do you prefer a shot glass of cool water, to wash down your crema heaven?
In continental Europe, a glass of cool water with your espresso is the service norm and from my perspective adds a certain importance to the art and ceremony which is perfetto espresso…..others in the ‘why make perfection better’ school of thought may disagree…
It is clear that in green form beans typically have 9 > 13% residual moisture- this being largely dependent upon origin… and that when the beans are roasted, all of this moisture is removed…hence delivering the ‘fabled’ crack…
But the interesting question is, in technical roasting terms, are beans which are quenched with water or air dried in a cooling tray, superior or preferred?
Again opinion is split… quenching smacks of industrial roasting, but is also the simplest, cleanest, safest and most effective way to end the roasting process and deliver a consistently great product.
Air drying on the other hand symbolizes the craft of the artisan roaster….. but also delivers a less consistent product, which is subject to broken beans and of course contamination from foreign bodies as the system is not closed…
The simple reality is, that I would challenge many so called espresso experts to discern any difference in cup, between an air dried espresso, with zero residual moisture and a quenched espresso, with 3 > 4 % moisture. Here in Europe the legal maximum is 5% residual moisture content.
Ok the crema may have marginally less longevity from a quenched espresso, but as we all know (and now for the technical bit!) Espresso crema is a biphasic system, composed of gas globules held within liquid films called lamellae… these globules are typically in a honeycomb structure…
Limited residual moisture content will therefore not detrimentally affect the persistence or quality of the crema, rather any error in judgement when grinding, brewing/ extraction / temperature is much more likely the root cause of an under performance.
As I say the devil is always in the detail…but then that’s why the art of espresso is a subject which raises such passions and opinions…. 
About the author: This article was written by Guru at aromocoffee.co.uk, the UK’s leading online retailer of ESE coffee pods.
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