Lard is commonly used in many cuisines around the world as a cooking fat or shortening, or as a spread similar to butter. It is an ingredient in various savoury dishes such as sausages, pâtés and fillings, and it is particularly favored for the preparation of pastry because of the "flakiness" it brings to the product. Its use in western contemporary cuisine has diminished with the increased popularity of vegetable oils, but many contemporary cooks and bakers still favor it over other fats for certain select uses. The culinary qualities of lard vary somewhat depending on the part of the pig from which the fat has been taken, and how the lard is processed.
Lard can be obtained from any part of the pig where there is a high concentration of fatty tissue. The highest grade of lard, known as leaf lard, is obtained from the "flare" visceral fat deposit surrounding the kidneys and inside the loin. Leaf lard has little pork flavor, making it ideal for use in baked goods, where it is valued for its ability to produce flaky, moist pie crusts. The next-highest grade is obtained from fatback, the hard subcutaneous fat between the back skin and muscle of the pig. The lowest grade (for purposes of rendering into lard) is obtained from the soft caul fat surrounding digestive organs, such as small intestines, though caul fat is often used directly as a wrapping for roasting lean meats or in the manufacture of pâtés.
Lard may be rendered by either of two processes: wet or dry. In wet rendering, pig fat is boiled in water or steamed at a high temperature and the lard, which is insoluble in water, is skimmed off the surface of the mixture or separated in an industrial centrifuge. In dry rendering, the fat is exposed to high heat in a pan or oven without the presence of water (a process similar to frying bacon). The two processes yield somewhat differing products. Wet-rendered lard has a more neutral flavor, a lighter color, and a high smoke point. Dry-rendered lard is somewhat more browned in color and flavor and has a lower smoke point. Rendered lard produces an unpleasant smell when mixed with oxygen.
Industrially-produced lard, including much of the lard sold in supermarkets, is rendered from a mixture of high and low quality fat sourced from throughout the pig. Lard is often hydrogenated to improve its stability at room temperature. Hydrogenated lard sold to consumers typically contains fewer than 0.5 g of transfats per 13 g serving. Lard is also often treated with bleaching and deodorizing agents, emulsifiers, and antioxidants such as BHT. These treatments make it more consistent and prevent spoilage. (Untreated lard must be refrigerated or frozen to prevent rancidity.)
Consumers wanting a higher-quality source of lard typically seek out artisanal producers of the product, or render it themselves from leaf lard or fatback.