This common vinaigrette ingredient has untapped emulsifying potential.
In our Foolproof Vinaigrette (see recipe in related content), we use 1/2 teaspoon of mayonnaise to keep normally incompatible oil and vinegar combined after whisking. Mayonnaise works well in this role because it contains egg yolks, which are rich in a phospholipid called lecithin, a superb emulsifier. Lecithin coats the surface of water droplets, preventing them from merging with one another and helping them remain suspended in oil.
Mustard contains a carbohydrate called mucilage that acts as an effective emulsifier. That’s why mustard powder often shows up in dressings. But there’s another common vinaigrette ingredient with untapped emulsifying potential: garlic. We found that 1⁄4 teaspoon of garlic paste (made by mashing minced garlic and coarse salt with the side of a chef’s knife or by rubbing a clove on a rasp-style grater) per 1⁄4 cup of vinaigrette worked nearly as well as mayonnaise to stabilize dressing. Chopped or finely minced garlic, on the other hand, showed little emulsifying ability, since the emulsifiers remained bound within its cell walls.