Espuma is simply Spanish for foam, but has become the culinary word of choice to describe the bit of froth that’s piped over, under or alongside food.
Purists will say that espuma is not merely a foam, and that using a gadget such as the iSi Gourmet Whip PLUS or iSi Thermo Whip PLUS you can make an exquisite foam (or, then, an espuma) of purées, coulis, creams, extracts or juices. It allows you to completely, or partially, do away with cream or egg as an emulsifier.
According to the celebrated Spanish Chef Ferrán Adriá, this new technique makes it possible to see and taste the “soul” of a food for the first time.