To some critics, foam is the symbol of all that is wrong with “modern,” “modernist” or “molecular” cooking. Foam is full of gas, they say, with no substance, metaphorically as well as literally. Its only function is to show that the chef is modern, and desperately trying to capture the culinary zeitgeist in his siphon. Culinary foam has become a cliche: little of it on top of a scallop is expected, not surprising.
But remember: Foam was not built in a day, and certainly not in a lab-like kitchen over the past 15 years. It has been a part of what we eat for centuries, if not millenniums. The modern foams are just a handful of new recipes to add to a plethora of old ones.
Foam is bubbles — gas — enclosed in, well, more or less anything. It can be protein, fat, gel or even a solid or semi-solid substance. Steamed milk is foam. That foam is, like the bubbles that form on top of your pot of boiling stock, protein-based. Whipped cream is a different type of foam, based on fat. Then there are foams based on starch, or created by the viscosity of a liquid. (If it is thick, it takes a long time for gas to escape.)
The realization that most people eat foam in one way or another every day might be a humbling reminder for the worshipers of modern foam: What you are doing is not so new. Even if the foam stabilizer you use has been on the market for only a few years, the mechanism behind it is more or less the same as the old-fashioned foams. It might also serve as a reminder for the detractors of foam: Yes, to worship foam is folly. And not every scallop dish requires it, or even benefits from it. But to declare that you dislike foam wholesale is to declare that you dislike everyday items such as cappuccino, whipped cream and bread, and treats such as souffle, spongecake, milkshakes, meringues and the bubbles on top of a glass of just-poured champagne, without which life no doubt would be a sadder, flatter place.
I think the problem is that we tend to forget the craft that lies behind the old foams. A few years ago, I was touring the country promoting a book on Scandinavian cooking. For most television appearances I chose to make what was certainly one of the simplest recipes from my book: Veiled Farm Girls, a traditional dish consisting of layers of whipped cream, applesauce and cinnamon-toasted bread crumbs. I chose it because it was simple and foolproof. But I was shocked by how often I heard comments about the cream.