The primary ingredient in rye bread is rye flour, which is made from ground rye grain. Rye is a cereal grain closely related to wheat and barley, and it has a distinctive flavor that contributes to the unique taste of rye bread. Rye bread is often denser and has a darker color compared to wheat bread, primarily due to the high fiber content found in rye flour. It is commonly consumed in various forms around the world, including the popular pumpernickel variety. Rye bread is valued not only for its taste but also for its nutritional benefits.