March 2004

Toss Your Salad With an Emulsifier
The Kitchen Samurai

I've never been a math guy, and the sciences really never did much for me either. I was always happier reading Faulkner than solving algebra problems, and The Periodic Table of the Elements might as well be hieroglyphs on a pyramid wall for all I can make of either of them. But my obsession with food is a harsh mistress, and it leads me to do terrible things sometimes, and, occasionally, I find myself learning science against my will.

It shouldn't surprise me, I suppose. Making food, really, is science applied: searing a steak is just the physical transference of heat from pan to beef, and when you judge that steak is done to your liking all you've done is make a value judgment about how coagulated you like your proteins, so really it's no surprise that even the most amateur of cooks sometimes find themselves pondering problems of a chemical or physical nature when all they wanted was a quick salad.

Of the various things I've learned about food, one of my favorites is the concept of the emulsion. An emulsion is simply a liquid suspended in another liquid, though it looks more complicated than that. As I understand it, molecules of one liquid end up getting caught between molecules of a second liquid and held there for a finite amount of time. Think of oil in water: if you add oil to water, the two do not mix. If you stir, however, you can, for a time, induce the oil droplets to separate, and watch them spread into discrete droplets held in the water. This is a simple, though very unstable, emulsion.

Butter, too, is an emulsion. When cold, butter is an apparently homogenous mass. As long as the butter is in your fridge, it's a fairly stable emulsion, but what if you add heat? If you heat butter until it melts, you'll begin to see it separate; this is the emulsion breaking down. If you heat butter until it boils, you can more clearly see the components from which the butter is comprised: water, milk solids, and milk fat. (If you keep boiling, you can watch the water boil off and see the milk solids settle to the bottom of the pan -- once those solids are settled, pour the clear yellow liquid that's left into a jar. Congratulations, you just clarified butter.) Butter, then, is an emulsion of butter fat suspended in water, an emulsion which remains stable until the introduction of heat.

All this is nifty I know, but what makes emulsions really cool are their uses in preparing meals. Hollandaise sauce, a beurre blanc, mayonnaise -- all of these are emulsions. My favorite emulsion though, hands down, is the lowly vinaigrette. A vinaigrette, in its simplest form, is not itself much more than oil in (acidulated) water in the form of either citrus juice, vinegar, or some combination of the two. Alone, these ingredients don't really mix and you're unlikely to get a smooth, pretty emulsion. If you add something to help stabilize the emulsion, though, you can create a beautiful, rich-looking sauce for not only salads, but pork tenderloins, egg dishes, fish... you name it. These stabilizers are emulsifiers and they're anything that will help to separate the molecules of the base liquid. Emulsifiers can, depending on your mood, be mustard, yogurt, sour cream, ground coriander seeds, or nearly any other powder or creamy condiment.

As an example, let's dress a salad with a quick vinaigrette. To stabilize it, we'll add a dab of mustard to the mixture. First, assemble some greens in a bowl; arugula, romaine, and dandelion greens will do. Next, ready a lemon, some salt and pepper, a little mustard, a container of olive oil that you can easily pour (if your olive oil container is unwieldy, use a measuring cup), and a clove of garlic, if you desire. In a fresh bowl, squeeze the juice of half a lemon, straining out the seeds with your fingers. To the lemon juice, add salt and pepper to taste, and a clove of very finely minced garlic if you like. Add a teaspoon of mustard, , and whisk the ingredients in the bowl until combined. Now, get ready to emulsify. To accomplish this, you're going to add olive oil to the bowl slowly, in a steady, thin stream, almost a trickle. The important thing is to incorporate the oil into the lemon juice completely. When you're ready to add the oil, first stabilize the bowl (perhaps with a wet towel beneath the bowl) so the bowl doesn't start spinning as you whisk. Next, start whisking the mixture in the bowl. With your other hand slowly begin to pour the olive oil into the bowl so that your whisking motion beats the oil into the lemon juice-mustard mixture. Keep adding oil and whisking continuously until the mixture is thick and creamy. Taste and adjust seasoning as you like, and add it to the mixed greens just before serving.

If, while you're whisking the oil into the bowl you slip and add a large glop of olive oil all at once, don't panic, just stop pouring and beat in the glopped oil as best you can. If your vinaigrette doesn't cohere the way you want, don't despair, just pour the not-quite-mixed vinaigrette into a second bowl, whisking in the second bowl as you pour -- sometimes this rescues a broken vinaigrette neatly. And, at last, if your vinaigrette never works quite right, even after pouring it into a second bowl, there are always two options available to you: you can resort to the blender, which might well beat your vinaigrette into an emulsified surrender, or you can just your vinaigrette as is, crying, "I meant to do that!" as you serve your friends. They'll never know, and you can always surprise them with a pretty emulsion the next time.

What makes this procedure so wonderful is its universality: the same steps can be used to emulsify any sort of vinaigrette for any sort of meal. Any acid can be combined with an oil, an emulsifier, and some aromatics or flavoring if you like, and a vinaigrette is born. For instance, combine lime juice, canned chipotles, and olive oil using the adobo from the can as an emulsifier. Top slices of rare tuna with a vinaigrette of shoyu, lemon juice, and peanut oil using wasabi powder to stabilize the emulsion. Create a salad of sliced red onions, orange sections, and avocado slices and dress it with a vinaigrette made from orange juice, sherry vinegar, and grapeseed oil using a dab of sour cream to emulsify it. The list is endless, bounded only by your pantry and your creativity.

Seriously, go try it. Vinaigrettes are one of those simple techniques that few ever bother to master, but, if you do, you'll be well on your way to becoming an excellent cook. To do something so simple very well is, in many ways, more impressive that pulling off culinary trapeze acts. Instead of dazzling your guests with pyrotechnics, next time try using a vinaigrette to awe them instead with quiet confidence and mastery. Your guests will thank you.