Two basic types of emulsions exist, which are oil-in-water and water-in-oil. A vinaigrette sauce is the oil-in-water variety. We use the term "water" because vinegar is about 95 percent water. Its oil is dispersed in the form of tiny droplets in the water. Milk and mayonnaise are also examples of an oil-in-water emulsion. Butter, in contrast, is an example of a water-in-oil emulsion. Its water is dispersed as tiny droplets in the oil.
** Asian Recipes