The ash applied to cheese once came directly from a fire, but is now mainly made from salt and vegetable ash (vegetables that are dried and turned into ash). The ash is sterile, odorless and tasteless.
Visual contrast:
A line of dark ash running down the middle of a cheese is visually stunning. Humboldt Fog from California and Morbier from France are cheeses that use ash in this way. French goat cheeses that are pure white in the middle with a dark ash rind, such as Valencay and Selles-sur-Cher, use ash partly for a visual statement, too.Protection:
Used on the outside of a cheese, ash helps form a thin rind. This can be seen on cheeses like the Italian cheese Sottocenere al Tartufo and the French Saint Maure. Long ago, ash was also used to protect the inside of cheeses, such as Morbier. When making this cheese, the cheesemaker would pour leftover curds into a mold and cover the curds with a thin layer of ash to protect it from flies until the cows were milked again and more cheese could be made. Now Morbier is made from one milking, but the traditional line of ash remains.Ripening:
Acidity in cheese can inhibit ripening, preventing cheese from reaching its optimal flavor and texture. Ash is an alkaline substance that neutralizes acidity and aids in the ripening process. Many of the French goat cheeses are examples of using ash in this way.

