What is an "emulsifier"?

Answer 1

Something which keeps two liquids mixed up when they don't want to be.

For example, if you mix oil and vinegar together for an Italian dressing, you'll notice that after a while they separate -- the oil floats on top. However, if you whisk them together with a little Dijon mustard, they stay mixed. Why? The mustard acts as an emulsifier -- that is, the granules of mustard absorb the oil and the vinegar and keep them in a fine suspension, giving them a smooth appearance and texture.

Flour can sometimes be an emulsifier, especially if you're thickening a sauce with butter. Here's a recipe for a rich onion gravy (try it on mashed potatoes, roast chicken, or anything else):

1 medium yellow onion, sliced thin
1/2 stick butter
2 oz water
Salt and pepper to taste
2 tablespoons flour
1 can (14.5 fl. oz) beef broth

Melt the butter in a heavy skillet over medium-high heat; when foam subsides but before butter browns, add thin-sliced onions. Cook till onions begin to turn brown and look ALMOST as if they're burned; add water (carefully, it'll immediately turn to steam and can scald you), then stir. This dissolves the caramelized sugars from the onions and turns the whole dish a gorgeous deep brown.

When the water has evaporated, sprinkle in the flour and stir carefully to coat all the pieces of onion. It'll look lumpy and ugly; bear with me for a moment.

Add about a quarter of the beef broth bit by bit, in a thin stream, and always stirring to mix it in with the butter/flour mix that's coating the browned onions. Keep stirring, over medium-high heat; add another quarter of the can. The object is to stop adding broth when the stuff in the pan is thick enough to be a nice gravy for you. When it's thick enough, turn off the heat, pour it into a gravy boat, and serve it.

Here's why the flour acts as an emulsifier: if all you did was pour melted butter into beef broth, the butter would float on the top of the broth (and if the broth was room temperature, the butter would start to congeal and be disgusting). But when you added the flour to the butter and onions, the flour soaks up the butter and starts to release its own starches. Then, when you add the beef broth, the rest of the starch in the flour dissolves into the stock, taking the butter with it and keeping it nicely distributed throughout the liquid. As the starch cooks, it thickens (and also as the water evaporates out of the pan, the starch thickens as well).

Enjoy!

Answer 2

it's the corporation of two liquids or more that forms another liquid. oil and vinger combine to create vinaigrette (dressing) eggs, oil, mustard and lemon ...creates mayonaise.... heated ...hollandaise (with out the mustard). Emulsifiers for these items above would be honey or mustard.

Answer 3

A surface-active agent that promotes the formation of an emulsion

Answer 4

Something that allows fats to mix with water based liquids without separating.