timo888 wrote:I am not setting levers against pumps but pointing out that low brew pressure and high brew pressure produce different results in the cup. (If you can play the pump pressure like a violin, great. ) Low brew pressure, in my experience, allows the more fleeting and delicate aromatics to emerge -- floral scents, for example -- not overpowered by the more intense flavors and aromas that get extracted at higher brew pressure.
And by 'low', I mean 3-6 bar.
I appreciate your statement not to set levers up against pumps, because I think that kind of narrow-minded approach is usually counterproductive.
I'm not sure exactly what you're saying about the delicate flavors, though. You appear to say that you value delicate flavors above all else, and are willing to sacrifice more intense flavors and aromas.
This is all, unfortunately, just theoretical, because we aren't standing side by side tasting from the same demitasse. Talking conceptually, however, I imagine you'd agree that both the intense and the delicate aspects of espresso are important, and we all try to find a pleasing compromise.
In Illy's book, Petracco has an interesting take on the pressure vs quality conundrum:
"The pressure value universally applied in professional espresso preparations, where a centrifugal pump is employed, is 9 relative atmospheres....This value results from a series of 'trial and error' attempts in the early years of espresso machine technology, whose results were measured by consumer satisfaction. It is interesting to point out how an alert espresso operator is in a good position to test any slight variation in coffee preparation procedures, judging immediately from the consumer's face (a genuine sensor) and drawing useful indications for further trials. In the course of time, such a method has established the optimal pressure level that minimizes failure possibilities in obtaining a perfect espresso."
