Vinaigrette is a mixture of vinegar (or sometimes citrus juice) an oil, often flavored with herbs, spices, and other ingredients. There are many ways to prepare Vinaigrette but a basic recipe is to slowly add 3 parts of oil at room temperature to 1 part of vinegar until it emulsifies into a smooth sauce. Salt and pepper are added for taste. Herbs are sometimes added to enhance flavour. The addition of a small amount of mustard can help keep the oil and acid in an emulsion. In France, Vinaigrette is often prepared once a week in large quantities.