cheese focus
Understanding how and why rinds are created is the first step in demystifying cheese for your staff and your customers.

Although we don’t always consume the rind, that exterior defines a cheese. Experts often categorize cheeses by rind type—bloomy, washed, natural, rindless—and the rind largely determines a wheel’s lifespan and flavor potential. Understanding rinds—how they got there, what their role is and how to protect them—will make you a more skilled cheese professional.

Rindless cheeses include fresh products like spreadable chèvres, foil-wrapped wheels like Roquefort and Point Reyes Blue, and vacuum-packed cheeses like block Cheddars. They have no rinds either because they are fresh and unripened or because they aren’t exposed to air during ripening.

But most specialty cheeses have a coat of some type, and cheesemakers rarely leave that aspect to chance. By manipulating surface moisture, salt content and pH, cheesemakers can influence, if not entirely control, what microorganisms grow on a rind.

Surface-Ripened Cheeses
These cheeses rely on microorganisms on the exterior to galvanize ripening. The active organisms can be molds, bacteria, yeasts or some combination. Their mission: to produce enzymes that break down the cheese’s protein and fat, thereby softening the paste and generating aroma. Let’s divide this category further:

Mold-ripened cheeses include those with bloomy rinds, such as Camembert, and those rare cheeses with external blue rinds, such as Westfield Farm’s Classic Blue Log and Spain’s Garrotxa. The bloomies get their white coat from Penicillium candidum, either added directly to the milk or sprayed on the young cheeses. Other Penicillium strains, such as P. roqueforti and P. glauca—are enlisted to produce the bluish molds.

Neville McNaughton, a St. Louis-based cheese consultant, says that the ideal bloomy rind is evenly thin—as thin as possible—and edible. (These rinds tend to develop an ammonia aroma as the cheese matures. Some consumers prefer to cut the rind away, especially if the scent is obvious or if the rind is thick.) Novice producers of bloomy-rind cheeses tend to overgrow the mold, points out McNaughton, “because they think it looks so beautiful. But the next thing you know, you’ve got ammonia and a really runny cheese.”

The bloomy rind on a Crottin di Chavignol, Redwood Hill Crottin or Vermont Butter & Cheese Bijou comes from Goetrichum candidum, a microorganism with both yeast and mold forms.

“The signature sign of Goetrichum is the wrinkly, brainy surface,” says Mateo Kehler, cheesemaker for Jasper Hill Farm in Vermont. Geotrichum neutralizes, or de-acidifies, the cheese surface, making it easier for other molds, yeasts and bacteria to grow. When you see crottins with blue spots, that’s what’s happening, says Kehler. “If you just have a plain Geotrichum rind, you’re going to get other molds growing on top of it.”

Like Geotrichum, powdered vegetable ash helps neutralize the cheese surface, so molds can proliferate. French goat cheeses like Sainte-Maure and Valençay exploit the ability of ash to create a stable mold rind. “It’s beneficial,” says McNaughton, “but I wish I knew why somebody thought to do that.”

Bacteria-ripened cheeses, often called washed-rind or smear-ripened cheeses, include varieties such as Munster, Taleggio, Red Hawk and Grayson. Alpine and alpine-style cheeses such as Comté, Appenzeller and Pleasant Ridge Reserve also belong to this group. Washing the wheel frequently with brine creates a moist, salty surface that molds can’t tolerate but that desirable bacteria like. Some cheesemakers add bacteria—typically Brevibacterium linens—to the wash. Others count on ambient bacteria.

Armed with the brine and a soft cloth, the cellar crew typically works from the oldest cheeses back to the youngest, a method that inoculates fresher cheeses with bacteria from mature ones. Mountain cheesemakers developed the process to slow the decay of wheels stored in moist, damp cellars. “The purpose was preservation,” says McNaughton. Today, robots do this tedious job in cellars in France and Switzerland.

The telltale sign of B. linens growth is a reddish-orange to caramel-colored hue on the cheese’s surface. These bacteria, as they break down proteins, generate the dirty-socks and garlic aromas that characterize washed-rind cheeses.

The rind on a bacteria-ripened cheese is edible and, some aficionados would argue, part of the cheese’s appeal. Because of the brine wash, the surface often delivers a pleasantly salty crunch.

Wild Rinds
These cheeses, sometimes called natural rinds, emerge from what nature provides. “Whatever is in the air is what grows on the cheese,” says McNaughton. “Nobody inoculates them with anything.”

Tomme de Savoie, Vermont Shepherd, Gorwydd Caerphilly, Cabot Clothbound and traditional Cheddars fit into this category. Although producing a wheel with a natural rind may sound like laissez-faire cheesemaking, it is anything but. The wheels need to be brushed periodically to keep mold growth under control and turned frequently so the rind develops evenly.

“The more mold you have, the more potential there is to raise a healthy crop of cheese mites,” says Kehler, who matures the Cabot Clothbound wheels in Jasper Hill’s caves. Vacuuming the wheels keeps the mites in check but at high labor cost.

However, Kehler puts clothbound cheeses like the Cabot, Montgomery’s Cheddar and Fiscalini Bandaged Cheddar in a separate wild-rind category than a Tomme de Savoie, for example. Clothbound wheels are often rubbed with lard, which gives molds something to feast on. The cheesecloth also contributes to rind formation. “Something about the cloth causes a lot of green and blue molds to develop,” says the cheesemaker. “The cheeses we’ve larded and rinded without cloth tend to be a lot whiter.”

A healthy wild rind should be dry and intact, with no cracks that allow blue mold to enter. The blue mold isn’t harmful, but it does create wastage for retailers who have to cut it away. In general, this kind of rind is hard to eat and does not add to the pleasure of the cheese.

Dry Rinds
A dry rind process, which is used on Parmigiano-Reggiano and Gouda cheeses for example, helped cheesemakers of earlier times respond to a dry climate. By sealing the wheel with olive oil or wax, they could slow moisture loss. Today, cheesemakers use vinegar or a brush to keep molds from establishing on these rinds. Or they coat the wheel with polyvinyl acetate, a thin sealant that still allows the cheese to breathe. Many producers add natamycin, a synthetic mold inhibitor, to the coating. Rinds with these mold-retardant coatings are not edible and should be cut away before consumption. Overall, dry rinds tend to be hard to eat and they can distract from the pleasure of the cheese.

Cheese rinds are complex microbiological worlds that can take a lifetime to understand. But learning to recognize the many types is a key place to start. |SFM|

Janet Fletcher is a staff writer for the
 San Francisco Chronicle and author of
 The Cheese Course.