Moldy Cheese Day

An Invitation to Embrace the Mold

October 9 is Moldy Cheese Day, a chance to celebrate the very molds that transform milk into some of the world’s most beloved cheeses. While the name might inspire jokes about cleaning out the refrigerator, this holiday honors a deliberate and delicious kind of mold. For centuries, cheesemakers have harnessed naturally occurring fungi to turn perishable milk into culinary treasures, creating flavors that are as bold as they are unique.

Legends and Origins

People have been curdling milk since ancient times, but the discovery of mold-ripened cheeses was likely an accident. One legend tells of a shepherd who left his lunch of bread and cheese in a cool cave. When he returned weeks later, the bread’s mold had spread to the cheese, turning it blue. Instead of discarding it, he tasted it and found a tangy, savory delight. True or not, caves in Roquefort-sur-Soulzon, France, and aging rooms in Gorgonzola, Italy, played essential roles in developing iconic cheeses like Roquefort and Gorgonzola, where naturally occurring molds thrived in stone walls and damp air.

The Science of Mold-Ripened Cheeses

Today, cheesemakers intentionally introduce molds such as Penicillium roqueforti, Penicillium glaucum, and Penicillium camemberti to create distinct flavors and textures. Blue cheeses are pierced with needles to allow oxygen inside, encouraging veins of mold to grow and deepen the flavor. Bloomy rind cheeses like Brie and Camembert develop snowy exteriors that protect and soften the creamy interiors. From England’s Stilton to Spain’s Cabrales, each region produces mold-ripened specialties influenced by local milk, climate, and tradition. American artisanal cheesemakers, too, have embraced the craft, experimenting with bold new profiles and aging techniques.

A Feast for the Senses

Moldy Cheese Day invites you to explore and taste. Notice how the aroma of a blue cheese can be grassy, nutty, or mushroomy. Watch how Brie or Camembert oozes at room temperature. Taste how a wedge of Roquefort crumbled over steak transforms a dish or how a mild goat blue like Humboldt Fog pairs beautifully with crusty bread. Safe molds—blue, green, and white—are central to these cheeses, while black or fuzzy molds on cheeses not intended to be moldy signal spoilage. Understanding the difference helps us appreciate the line between science and spoilage, between accident and artistry.

Why Moldy Cheese Day Matters

Behind each wheel of cheese is a story of patience and craft. Cheesemakers tend caves, monitor humidity, and brush rinds as microorganisms break down fats and proteins into evolving flavors. A bite of blue cheese is a taste of alchemy—milk, mold, and time working together. National Moldy Cheese Day encourages us to honor that craft, to replace hesitation with curiosity, and to find joy in the flavors that mold brings to the table.

Ways to Celebrate Moldy Cheese Day

• Create a cheese board: Sample a mix of blue cheeses, bloomy rinds, and triple-crèmes alongside fruit, honey, and nuts.
• Pair with food and drink: Try Roquefort with steak, Brie with apples and honey, or Camembert with sparkling wine.
• Learn the craft: Visit a local cheesemonger, ask for a tasting flight, and explore how mold shapes flavor and texture.
• Try something new: Step outside your comfort zone with Cabrales from Spain or an American artisanal goat blue.
• Share and savor: Gather friends, talk about the history and craft of cheese, and discover that moldy cheese is a treasure worth celebrating.