If you tuned into the premiere episode of season five of "Top Chef" last week, you may have witnessed a moment that seemed to capture the (entertaining) absurdity of turning cuisine into fodder for a reality show: A curious argument broke out between Stefan, the smug, Finnish-born, German-raised caterer, and Danny, the Long Island-based chef and resident New Yawker, over whether or not a vinaigrette is an emulsion.
The conversation went something like this:
DANNY: It's an emulsion. The technique of making vinaigrette is an emulsion.
STEFAN: A vinaigrette is not an emulsion.
STEFAN: Come on! Get a life!
So, is a vinaigrette an emulsion?
Seeking a definitive answer to this critical question, I lugged out my copy of Alan Davidson's Oxford Companion to Food and looked up vinaigrette, which was defined as "a 'mixture' (inverted commas because oil and vinegar are, strictly speaking, immiscible) of olive or other oil with vinegar (or lemon juice or the like or a combination of some vinegar and some lemon juice)."
This put me in the mood for a salad, but there was no mention of the word "emulsion," so it didn't solve our conundrum.
I consulted writer Harold McGee, who is esteemed as an authority on the science of food and cooking. He emailed me this simple and succinct solution to the vinaigrette puzzle: "An emulsion is a combination of two liquids that can't mix evenly with each other, typically water and oil. One liquid is dispersed into the other in the form of separate droplets," He wrote. "A vinaigrette is a suspension of vinegar droplets in oil, so yes, it's an emulsion." Case closed.
Now, perhaps Stefan was thinking narrowly only of those emulsions that contain emulsifiers
to stay together. As anyone who has made a basic vinaigrette knows,
oil and vinegar will eventually separate into their original components
(without more whisking). On the other hand, an emulsion like
mayonnaise, which combines oil, lemon juice, and egg yolks, doesn't
break down because of the presence of lecithin, an emulsifier, in the
yolks. Similarly, adding some mustard to a vinaigrette will help to slow the separation of the oil and vinegar.
So, Stefan was wrong. A vinaigrette is an emulsion.