Stocks are prepared with a few basic ingredients including bones, mirepoix, herbs and spices, and sometimes tomatoes or wine. They are often prepared using leftover ingredients as a cost-effective measure for the kitchen.
Always remember to make sure the ingredients are of good quality, a stockpot should never be a dumping ground for old leftovers that are past their prime.
Meat trimmings can be added, as long as they are cleaned of fat and gristle. Aromatic vegetables, usually onions, celery, and carrots, are typically incorporated. Substituting leeks for the onions, or adding garlic, enhances the flavor of a stock. Tomatoes are incorporated in brown stock for color and flavor; they also add acidity and help clarify the liquid.
When preparing a fumet, nage, or court bouillon, white wine is added for flavor and acidity. Standard seasoning includes parsley, bay leaf, thyme, and peppercorns. Other herbs and spices augment the flavors as desired. Vegetable stocks begin with a mirepoix of onions, celery, and carrots, enhanced by additional vegetables, leeks, garlic, mushrooms, tomatoes, fennel, and similar ingredients.
