Get a hand lens ready. You’re going to want to take a closer look at this astonishing cheese rind. It is quite the wild kingdom, a thick crust of colorful, coexisting microbes. I’m not sure I have ever seen a more riveting surface on a cheese: suede gray, dusty brown, ivory, powdery yellow. rose and rust.

“Yeasts are thought to be responsible for the orange and pink, including on all washed-rind cheeses," says Gianaclis Caldwell, author of Mastering Artisan Cheesemaking, when I sent her the photo for comment. ”That looks like what's going on on the edges. In the old days, multi-flora rinds were more common.”

Researchers still don’t know what these various microbial actors contribute—only that they do contribute to the evolution of cheese aroma and texture by slowly breaking down fat and protein. They also likely protect cheese from bad actors such as Listeria by out-competing them.

To a microbiologist, a cheese rind is a “biofilm” or a “multi-species microbial community.” A study of cheese-rind communities funded by the National Institutes of Health revealed some fascinating insights. The researchers examined 137 different cheeses from 10 countries, including the U.S. I’m greatly oversimplifying, but here are some highlights:

On average, each cheese rind hosted six to seven different bacterial genera and three fungal genera.
On average, across the samples, at least 60% of the bacteria and 25% of the fungi came from the environment (like the aging cellar), not the starter culture.
·Geography doesn’t contribute as much as you might think. The method, or make process, is more influential. “Cheeses made in geographically distant parts of the world can have strikingly similar rind communities,” the authors wrote, “demonstrating that these microbial communities can assemble reproducibly regardless of the cheesemaking region.” Sounds to me like a demotion for terroir.

That said, I don’t ever recall seeing an American cheese rind—excuse me, biofilm—like the one on Gelso Toma di Bufala (pictured above). Made by Caseificio Moris, a family farm and creamery in Italy’s Piedmont region, Gelso is a water-buffalo adaptation of a regional cow’s-milk cheese, the Toma Piemontese. The family has been farming and raising cattle here for more than a century; 15 years ago, they added 50 water buffalo and now have about 1,000.

Gelso debuted in 2010, made entirely with milk from the farm, from animals nourished exclusively with feed grown on the farm, so it’s a closed system. Mozzarella is the creamery’s cash cow, so to speak, but the toma offers more complexity. Matured for a minimum of 1-1/2 months, the 6-1/2-pound wheels are washed with brine several times during that period. They may look like they were ripened in some damp, craggy underground cave, but a temperature-controlled aging room does the job.

Under that crust is a semi-firm, smooth and dense ivory paste with scattered small openings. I get cultured cream, cheesecake and mushroom aromas, plus a hard-to-describe animal scent that I often find in bufala cheeses. The salting is perfect, the finish tart. It’s a lovely cheese.

Unfortunately, there’s not much of it. Look for Gelso Toma di Bufala at Haight Street Market, Le Beau Market and Rainbow Grocery in San Francisco; Oxbow Cheese Merchant in Napa; V. Sattui in St. Helena; Oliver’s Market in Santa Rosa, Cotati and Windsor; and Larchmont Village Wine, Spirits & Cheese and the Cheese Store of Silver Lake in Los Angeles.