The Science Behind Culinary Foam: Breaking Down the Bubbles, Liquid, and Flavor of This Modernist SpecialtyJuly 29, 2014
There is a danger to merely looking at the surface of well-arranged plate. Appearances alone impress, but take a closer taste and an extra look at how culinary staples like foam are made, and you’ll discover the intricate details, specifications, and factors that go into the work of the world’s most renowned chefs. Ferran Adrià of El Bulli was among the pioneers who brought much advancement to the now thriving international culinary scene. One of his most popular experiments involved foam—something that has always been in food, but a concept taken several notches higher with Adrià’s imaginative skills and efforts. But what exactly makes foam so special that it merits such praise and hype in the first place?
The Familiarity of Foam
Like the bodies we must feed and the weather that we (try to) read, foam adheres to principles and phenomenon that are studied in science. Without a basic of understanding of such science, none of us would’ve been able to know the best time for boiling an egg or why dry ingredients are combined separately from wet ones during baking. Foams are where the three properties of matter—solid, liquid, and gas—meet. Foams are either solids or liquids that have air or gas bubbles trapped within them. In more technical terms, foams are colloidal systems where in the gas bubbles are surrounded by thin films of liquid. Solid foam is usually eaten in the more familiar forms of sponge cake or bread. But more people tend to identify foam with the wet kinds seen in latte froths, milkshake froths, and whipped cream.
The difference among the various foam types lies in the amount of air and liquid. As its name clearly indicates, dry foams are lighter due to the dominance of air, while wet foams contain more liquid. Each type of wet foam ties that unique experience we look for in drinking a thick milkshake or that textured look you find in latte froth. There are also various types of wet foams: dense wet foams are thicker, while lighter foams achieve that harmony between the dense and airier kinds. The “fancy” type of foam seen in modernist cuisine is called “espuma,” which translates to foam in Spanish. Espumas are airier and don’t have as much texture, but maintain the flavor that’s needed for the viand or food the foam is resting upon. There are also dehydrated foams like meringues which are created by first beating egg whites and then dehydrated either with an oven on a low temperature or via a dehydrator.
The Science of Taste
It’s pretty clear how foams appear and taste, but how is foam able to maintain its appearance in the first place? With just air and liquid in the mixture, the air can only stay suspended for so long before it finally escapes and leaves the liquid. So how are foams able to maintain that texture and body, or even those bubbles for a certain amount of time? The answer lies in the process of emulsification. Molecular gastronomy employs this so that the air bubbles remain suspended in the liquid. Milk and egg-based foams such as whipped cream, fizzy drinks, and meringue maintain their body due to the proteins in the cream and milk. These proteins are the emulsifiers responsible for the foam’s formation and stability. The air itself is introduced through a force such as whipping or other types of whippers that make specific types of foam. An iSi whipper is the most popular choice for those who want to make all kinds of culinary foams. The foams made can be made according to the size of the bubbles and according to the preferred temperature serving. Ferran Adria’s technique involves a siphon that allows for the foam’s longer storage. The siphon can be sealed as soon as the mixture is prepared. Other techniques that introduce air into the foam mixture are manual and electric whisks, a standing and hand held mixer, a milk frother, and an aquarium pump or bubbler. The aquarium pump results in larger, soap-like bubbles, while the milk frother is what creates latte and cappuccino foams.
Modernist foams employ specific types of emulsifiers to achieve a specific type of texture and prolonged stability. Lecithin is a popular emulsifier as it doesn’t thicken the mixture but still stabilizes the foam. If you want to make your own foam at home, then methylcellulose and versawhip are recommended ingredients. They don’t require fancy equipment like a siphon and only require the use of a manual whisk to create the foam.
From the thinner foams plated on fine dining steak to the frothy moustache we get from downing a milkshake, foam can be a part of everyday eating. At the same time, chefs and cooks deal with the intricacies of the science that allows the foam to happen. So next time you take that Instagram photo of your fine dining plate or attack that cappuccino foam, take a moment to thank the universe for its unique design.