What Do You Know About Adding Water to Vinaigrette?

Faith's wonderful post on My Favorite Balsamic Vinaigrette yesterday reminded me of vinaigrette question I've had for quite some time now. It involves an unusual vinaigrette technique that I've only seen on occasion, but whenever I have, the results were spectacular.

A good friend makes the best vinaigrette I've ever tasted, perfectly balanced and unctuous. What is her secret? She uses a touch of mustard, true, and has an excellent instinct for salt. But her real secret, according to her, is that she adds a tiny splash of water to the mixture.

This sounds counterintuitive, of course. Don't we painstakingly dry our lettuce to remove as much water as possible/ Don't we avoid gloppy ingredients to keep our salads from getting soggy? Why then would we add water, if even a tiny splash, to the dressing?

I've searched the internet for the answer to this question but have come up empty handed. I once heard someone refer to this as a 'chef-y' trick and wonder if the science of it is taught in culinary school. I can't find anything in Harold McGee, whom I usually rely on for these kinds of inquiries.

If I were to take an unscientific stab at it, I would say that the water opens up the dressing a little, cutting some of the intensity between the contrast of the unctuous oil and the sharp vinegar. It helps to balance everything out. I also wonder if this is a way to cut some of the tang of an overly sharp vinegar without having to add more oil (which would mess with the ratio) or sugar (which some people don't care for in their dressings.)

But like I said, this is just a guess. Is there anyone out there who has some more practical knowledge of this? Do you add water to your vinaigrette?

Related: Dressing Spring Salads: How to Make a Basic Vinaigrette

(Image: Dana Velden)