Though some traditional breads are made without salt, most include it, and not just for a balanced taste. At 1.5–2% of the flour weight, salt tightens the gluten network and improves the volume of the finished loaf. (The tightening is especially evident in the autolyse mixing method, below.) Unrefined sea salts that contain calcium and magnesium impurities may produce the additional gluten strengthening that mineral-rich hard water does. In sourdoughs, salt also helps limit the protein-digesting activity of the souring bacteria, which can otherwise damage the gluten.