Cookbook:Blood

Animal blood is used as an ingredient in many cuisines.

Characteristics
Blood can be eaten from a variety of animals, including pigs, poultry, cattle and bison, and more. The exact qualities of the blood will depend on the animal—for example, chicken and pork bloods are considered mild in flavor, while beef blood has more of a "gamey" quality. All blood, however, is dark purple to bright red when raw (depending on its oxygen exposure) and brown when heated, with high levels of protein and iron. This iron content gives it a metallic flavor somewhat akin to liver, which can be desirable or not depending on the palate of the diner.

Selection and storage
Blood is highly perishable and is best used fresh —it keeps at most for a couple of days in the fridge. Freezing for long-term storage is also an option, though this can impact its texture upon thaw. To prevent undesired clotting, an anticoagulant may be added, such as an acid or salt that binds calcium. Before using the blood, it's best to strain to remove any clots that may have formed. 

Blood will smell metallic but should not have strong off or overly gamey scent or flavor.

Use
Though taboo in some cultures, blood has a traditional place in many cuisines, where it provides flavor, thickening capabilities, and nutritional content. Blood in sausages is common, as well as its use in soups and stews, and it is often paired with other strong-flavored ingredients. It can even be used in Scandinavian breads and pancakes.

Because of its high protein content, blood can be used as an egg substitute and whipped for use in foamed products like meringues and cakes. As a guide, 65 g blood will replace 1 whole egg (58 g) and 43 g blood will replace 1 egg white (33 g). Note that whipping blood requires more time and gradual speed increase in order to achieve a stable foam.