I like to read food magazines (no big surprise there). Cook’s Illustrated (Sept./Oct. 2009) did an article on making vinaigrettes. For me this was a great article. I like to make my own salad dressings. One problem that I have with homemade vinaigrettes is that the oil and vinegar separate into two layers. Shaking helps for a few seconds, but upon sitting for a few minutes they separate. Oil on top and vinegar on the bottom. That is because oil is less dense than vinegar. Alone they just can’t stay together.
To keep oil and vinegar together, you need an emulsifier. Emulsifiers have two ends. One end holds water (hydrophilic) and one ends holds oil (hydrophobic). Therefore emulsifiers act to bring oil and water together into one. Egg yolks contain an emulsifier, lecithin. This is why egg yolks are used to make mayonnaise.
Schematic for an emulsifier
So why not use a little mayonnaise to keep a vinaigrette together. You are essentially using an emulsion to make an emulsion. And it worked. The vinaigrette made with the mayonnaise was a little thicker and did not separate. I made a lemon vinaigrette using this method.
Makes about ¼ cup.
½ teaspoon mayonnaise or light mayonnaise
1 Tablespoon Dijon mustard
⅛ teaspoon salt
Black pepper, freshly ground
3 Tablespoons fresh lemon juice
2 Tablespoons extra virgin olive oil
1. In a small bowl whisk together mayonnaise, mustard, salt, and pepper. Gradually add lemon juice.
2. Slowly, add the oil, whisking constantly. Vinaigrette should be slightly thick with no oil on surface.
Note: Recipe makes enough to coat about 8 to 10 cups of salad greens. The original recipe only called for ½ teaspoon Dijon mustard. I happen to love Dijon mustard, so I added more. Finally, I also prefer more acid and less oil, so feel free to adjust the ratio of acid to oil.