#truecooking

GO FORTH, AND EMULSIFY

I’ve got an emulsion compulsion! This week, we’re all about bringing the world together in the form of culinary emulsions. Emulsions are defined by the process of bringing together two products that will maintain their individual characteristics after being combined. In short, mixing two immiscible items (liquids that don’t mix); fat and water. Think of it this way—you’re at a party and you spot that person across the room that you just can’t stand. They’re always going on about how great they are, and no matter what you say, this person has always done it first, done it more, and done it bigger. You throw up in your mouth a little to even think of engaging them in a conversation. Then the host of the party comes along and asks, “Have you met so-and-so?” You think to yourself, ‘Ugh!’ Well, the party host throws his arm around you and throws the other around Mr. or Mrs. Better-than-you, and the next thing you know, you’re all hanging out! This dynamic sort of describes what occurs in an emulsion. These two products that don’t care to hang out together must be combined and so, we use binding agents that act as a kind of glue to secure these molecules together.

Emulsions occur in two basic types; strong emulsions and weak emulsions. Strong emulsions are bound with agents to hold the sauce together. Weak emulsions have no binding agents and so, without the addition of stabilizers, the technique becomes all important.

EMULSIFIERS and STABILIZERS:

From a scientific standpoint, the water and fat products will do their level best to touch as little as possible. This is called “surface tension.” Even if one stirs the items together, they will still separate and return to their individual states. When cooks refer to a sauce as “breaking,” this is what they mean. The emulsion broke down and the liquids separated back to their natural states. To combat this, cooks will often employ emulsifiers that have fat friendly and water friendly molecules. Much like the party host that likes both of the guests, despite their dislike of one another. Sticking with the basics, there are two types of emulsifiers; amino acid chains and phospholipids.

Amino acid chains bind and form larger chains called proteins. Casein proteins, for example, are derived from dairy such as eggs, milk, and heavy cream which qualifies these substances as emulsifiers. Eggs, along with soy, contain lecithin, placing them in the second group of emulsifying agents as well, called, phospholipids. Lecithin products feature surfactant qualities which reduce surface tension in liquids to which they are introduced and bind both water and fat. On a molecular level, lecithin’s “tail,” which binds fat molecules, has a positive charge. This makes for a strong emulsifier by preventing the fats from pooling.

The two basic techniques are fat-in-water emulsifications and water-in-fat. As I explained, emulsifiers link fat and water molecules. Cooks often employ stabilizers such as proteins, plant product, gums, and starches, which thicken emulsions. These stabilizers are water soluble and therefore used mostly in fat-in-water emulsions. Their large molecules add viscosity which is helpful in stabilizing weak emulsions that require heavy agitation.

For example, a pan gravy in which the remaining oil (after cooking the protein) is combined with wine to deglaze the pan. Heavy cream is then added, slowly, while the mixture is constantly agitated with a rubber spatula to create cohesion.  If the emulsion is not agitated well enough, the molecules will separate. Simultaneously, if the liquids are over-agitated, the gravy will break. This is where the introduction of a stabilizer, such as a food grade gum, would thicken the emulsion.