ESPRESSO A LIFESTYLE:  BREWED ON THE SPUR OF THE MOMENT

One of the meanings of the word espresso (express) is that it is made for a special purpose, on the moment, on order, therefore made for the occasion on express request, extemporaneously rather than fast.  This concept is clarified by the saying “the consumer not the espresso must wait.”  As a direct consequence, once brewed, espresso cannot be kept, and must be drunk just after having been served.  If it is not drunk immediately, the foam shrinks and collapses, breaking into patches on the surface.  After a while, the surface of the liquid is completely free from foam, which has dried out on the walls of the cup above the liquid.

If an espresso is kept waiting, smoothness of taste is lost and perceived acidity increases with time regardless of cooling.  Furthermore, if the cup cools down, and unbalanced saltiness becomes noticeable.