Pepper flakes consist of dried and crushed red chili peppers. Chili pepper pods, which are berries, are used fresh or dried. There are over 300 subspecies of chili, each bearing fruit of different sizes, shapes, color, flavor and degree of hotness. They are all descendants of the same chilies discovered in the Americas by Spanish explorers in the 15th century. The spiciness of chili peppers is measured in Scoville heat units (SHU); from zero to pure capsaicin 16,000,000 SHU. The highest concentration of capsaicin is in the inner layer of the chili pepper, the wall surrounding the seeds. Pepper flake shakers have become a standard on tables at Italian restaurants. Pepper flakes are essential ingredients in pickling, chowders, spaghetti sauce, pizza sauce, soups and sausage.