Mirepoix

Veal, beef, and chicken bones are most commonly used. The flavour of the stock comes from the cartilage and connective tissue in the bones. Connective tissue has collagen in it, which gets converted into gelatin that thickens the liquid. Stock made from bones needs to be simmered for longer than stock made from meat (often referred to as broth). A combination of onions, carrots, celery, and sometimes other vegetables. Often the less desirable parts of the vegetables (such as carrot skins and celery ends) are used since they will not be eaten. The herbs and spices used depend on availability and local traditions. In classical cuisine, the use of a bouquet garni (or bundle of herbs) consisting of parsley, bay leaves, a sprig of thyme, and possibly other herbs, is common. This is often wrapped in a cheesecloth "bag" and tied with string to make it easier to remove it once the stock is cooked.

Broth is very similar to stock, and often the terms are used interchangeably. Usually, broth refers to finished product, while stock is used as an ingredient (thus stock may become broth). Other times, broth is used to refer to a liquid made in the same way as stock, but meat is substituted for bones. However, with some stock/broth made from vegetables and some made from both bones and meat, this cannot be considered a hard-and-fast rule.

Today, ready-made stock and stock cubes consisting of dried, compressed stock ingredients are readily available. These are commonly known as bouillon cubes (or oxo cubes, after a common brand of stock cube sold in Britain) or cooking base