A sauce made with egg yolks, olive or vegetable oil, mustard, and lemon juice or vinegar, and various seasonings. Combining all of the ingredients results in an emulsion being created, which involves the process of combining two liquids that do not typically mix together well, such as eggs and oil. Sauces or dressings that look like mayonnaise but which do not contain eggs as an ingredient, cannot be labeled as mayonnaise. Available as a traditional mixture of ingredients containing higher levels of fat, mayonnaise is also available in lighter versions that are considered low-fat and contain lower levels of fat content. Mayonnaise and its lighter versions are generally available in most food stores.
Rich in flavor and creamy in texture, mayonnaise is used as a condiment to be spread over foods such as sandwich breads or crackers, as a sauce enhancer that could be flavored with herbs, spices or bits of vegetables to be used as a dip, as a dressing for salads (when eggs are not used to make the mayonnaise), and as a thickener or base for other dressings. Mayonnaise is commonly made by hand to create a more flavorful dressing that is richer in taste and texture than commercial varieties. However, mayonnaise made by hand can only be stored for several days in a refrigerator. Commercially produced mayonnaise that has been opened can be stored refrigerated for up to 6 months after opening, while unopened containers can be stored in cool dry areas for periods of time that typically can extend beyond the "use by" date displayed on the label or container.