If you’re a fan of artisan cheese, you’ve probably encountered a cheese made with ash.

Maybe you thought the racing stripe running down the center of a wedge of Morbier was actually mold, or that the mottled rind of a pyramid of Valençay got its charcoal-gray color naturally. 

In fact, that striking black, blue, or gray is a thin layer of finely powdered ash put there by the cheesemaker—and not just because it looks cool. Ash has long been a part of cheesemaking, from traditional French recipes to contemporary American originals.

Why Is Ash Used in Cheesemaking?

For centuries, cheesemakers have used ash in cheese for several reasons: to protect the curds, help with rind formation, support the ripening process, and provide an attractive visual contrast to white mold or pale yellow paste. While it’s typically used on soft cheeses like bloomy rinds, ash can be found running through aged cheeses and is used to create a dramatic black color on the rind of some hard cheeses, too. 

What Kind of Ash Is Used in Cheesemaking?

Hundreds of years ago, a cheesemaker would have used a handful of ash raked from the fire used to warm the milk for cheesemaking. 

For example, legend has it that ash was first used in Morbier to protect leftover curds from the evening milking. The cheesemaker would sprinkle a layer of ash from the fire atop the curds to protect them from insects until the wheels could be topped with a batch of fresh curds the next morning. Now, Morbier wheels are formed whole, then split and sprinkled with ash. 

Today, the ash used in cheese is a fine, food-grade powder made from burning grapevines or wood. Ash doesn’t create a gritty texture, and it’s odorless, tasteless, and sterile—your body doesn’t even digest it. Some cheesemakers use activated charcoal, which is used as a food coloring in items from artisan bread to ice cream. 

That hasn’t kept the FDA from threatening this long-established traditional practice that research has proven safe: Between 2014 and 2016, the regulator halted imports of European cheeses made with ash, like Morbier, because the ingredient wasn’t on its list of approved coloring agents. Finally, ash was reclassified, and ashed imports were allowed into the country as they had been for years before. 

Which Cheeses Are Made with Vegetable Ash?

Aside from Morbier, ash shows up in a variety of cheeses—most notably the small, bloomy-rind goat’s milk varieties from France’s Loire Valley, such as Valençay, Selles-sur-Cher, and Sainte-Maure de Touraine. In these delicate cheeses, a sprinkling of ash along with the usual salt on just-formed wheels helps with rind formation—a key step in the life of the cheese. In Italy, the truffle-infused aged cheese Sottocenere al Tartufo is named for the ash layer on its rind—”sottocenere” actually means “under ash.”

In the United States, one of the most popular ash-rinded cheeses is Humboldt Fog. This California take on this classic French practice features ash on the rind and running through the center of the wheel. Bonne Bouche, produced by Vermont Creamery, is another great example of a brainy, wrinkly, Geotrichum-rind cheese made with vegetable ash. There are dozens if not hundreds of ashed varieties made around the world. 

We at Cheese Grotto sell several award-winning American artisan cheeses with ash in our online cheese shop. Green Dirt Farm in Missouri is known for Dirt Lover, an ashed round made with sheep’s milk. The curds of Sappy Ewe, a miniature sheep and cow’s milk bloomy from Nettle Meadow farm in upstate New York, are coated in a maple syrup reduction before the wheels are rubbed with a coating of pine ash. 

In Pennsylvania, Yellow Springs Farm makes Black Diamond, an American take on traditional Valençay. In North Carolina, Boxcarr Handmade Cheese treats its French-Italian cow’s milk hybrid Rocket’s Robiola with ash before aging. 

How Ash in Cheese Affects Rind Formation and Ripening

We know that these soft little cheeses are coated in ash to help develop their rinds—but why? 

After they’ve been drained and shaped into buttons, rounds, or pyramids, the surface of a freshly formed cheese is slightly acidic. It also needs a day or so to dry appropriately before the wheel can go into the aging cave. 

When combined with a little salt, ash helps with both of these things: A dusting of slightly alkaline ash will lower the acidity of the cheese surface. This creates the ideal conditions for the first of several successions of microbial communities to grow and gradually form the cheese’s bloomy rind. Since it absorbs water, it’s theorized that ash also hastens the drying process and helps preserve the integrity of the rind throughout its life. 

Because of these properties, ash benefits the cheesemaker in other ways beyond rind formation. Its alkalinity can help to modulate the ripening process, meaning that the cheese can age for longer without molds on the surface running wild. Ash can also balance a cheese’s acidity, which helps create the maker’s desired flavor profile in the finished product. 

What are your favorite cheeses made with vegetable ash? Did you know about ash in cheese? What surprised you about today’s post? Let us know and tag us @cheesegrotto on Facebook and Instagram!