How to Make a Vinaigrette or Other Emulsion
A vinaigrette can be as simple as vinegar and olive oil whisked together in a bowl. However, if you want an emulsified vinaigrette, there’s a few things that are good to know.
An emulsion occurs when water molecules and oil molecules bond, rather than repelling from each other. Whisking vinegar (water molecules) and olive oil (oil molecules) in a bowl creates a temporary emulsion – they will remain together long enough to toss a salad, but will then separate. For an emulsion to last longer, it must be stabilize.
One way to stabilize an emulsion is to add the oil to the water gradually, in a thin stream, while the water is in constant, rapid motion. This way, the oil is dispersed as much as possible throughout the water. Using a blender makes this a lot easier – a food processor also works. It is possible to make an emulsified vinaigrette in a bowl with a whisk though – I’ve done it at work when the VitaPrep blender was broken – but you’ve got to go at it full force with the whisking, non-stop, and stream the oil ever so carefully. One good trick is to keep the mixing bowl in place but placing a damp towel underneath it. This frees up your one hand for the whisk, and the other to stream the oil.
Another way to stabilize the emulsion is with emulsifiers. There are some salad dressing ingredients which bond to both water and oil molecules. These include mustard, egg yolks, and xantham gum (a powder available at specialty food stores).
Many vinaigrette recipes call for a small amount of mustard, just to help hold it together. Add the mustard to the vinegar, then proceed to stream the oil. The egg yolks are the reason that mayonnaise is such a strong emulsion – they create a tight bond with the oil. The same for Caesar dressing – the yolks bring the vinegar and oil together.
Many restaurant kitchens use xantham gum because it can be added to the vinegar much like mustard, and is an even stronger emulsifier (a little bit goes a long way!). However, unlike mustard, xantham gum is flavorless.
See the following posts for some good vinaigrette recipes:
Roasted Garlic & Shallot Vinaigrette
Roasted Beet Salad with Oranges and Curry Vinaigrette
Seared Skate with Fingerling Potatoes, Roasted Mushrooms, and Balsamic-Mushroom Vinaigrette
