For more than a decade, the buffalo-milk soft serve sold at the Palace Market drew acolytes from well beyond West Marin. Ultra-creamy and sumptuous, rich and airy yet almost chewy, it was, for many, the Platonic ideal of a swirled cone. 

But this week, unbeknownst to most, the beloved offering vanished, replaced by a version made with Jersey cow milk, the result of new ownership and a shifting supply chain.

The gelato first came on the scene around 2013, when Andrew Zlot, founder of Double 8 Dairy, a Valley Ford company that built its reputation on water-buffalo milk, began experimenting with the form. Mr. Zlot learned the craft from two Mendocino County gelato makers trained in Bologna, after tasting their product at a potluck and persuading them to try their recipe with buffalo milk.

 “What came out was just mind-blowingly good,” he said.

Mr. Zlot, who now lives in Mallorca, served the frozen dessert from a cart near Toby’s Feed Barn for one summer. Then, in what ended up being a “happy accident,” he brought leftover gelato next door to the Palace, where he was invited to feed it into the soft-serve machine. 

“I thought, either we break the machine or something good comes out,” he said. “And something great came out. That was the beginning of buffalo soft serve as a product identity, period.”

What oozed that day from the machine—which super-whips air into a liquid base that freezes at a slightly higher temperature than ice cream—was distinguished above all by the milk itself. Buffalo milk contains roughly twice the fat of typical cow’s milk, giving the gelato its distinctive dense and velvety texture. Unlike most soft serve, which relies on shelf-stable powdered mixes, Double 8’s version used a fresh gelato base, flavored with real vanilla bean—its specks visible in the pale swirl—or dark Guittard cocoa powder. 

“I think the big eye-opener for many people who tried the stuff was that buffalo gelato doesn’t taste weird,” Mr. Zlot said. “Most Americans associate milk with cows, and milk from any other species gets labeled as strange or gamey because the animal looks funny, or is hairy, or has horns.”

In the United States, water buffalo—large, prehistoric-looking animals with sweeping crescent-shaped horns—have an almost mystic exoticism. In Italy, by contrast, buffalo milk and its byproducts, most notably mozzarella, are ubiquitous. 

Americans have developed a taste for buffalo mozzarella, which is at its best when consumed fresh, the curds stretched and shaped just hours before. Yet most of what is available domestically is shipped thousands of miles from Naples. Mr. Zlot saw an opening, first working with famed West Marin buffalo man Craig Ramini before striking out on his own.

The change in his product comes as the result of a shift behind the scenes at Double 8 Dairy. In recent years, the operation split into two businesses: the farm that raises and milks the buffalo, and the creamery that processes the milk into finished products.

About three years ago, Mr. Zlot sold the creamery to his neighbors, Joe Moreda and his mother, Karen Bianchi-Moreda, who run Valley Ford Creamery. Last year, he sold the buffalo herd itself to Ty Renati, a fourth-generation Sonoma County dairyman. 

Under the new arrangement, Mr. Renati has prioritized a contract supplying the milk to a mozzarella producer in the Central Valley, leaving little available for gelato.   “The supply has been dwindling and dwindling,” Mr. Moreda said. “Point Reyes ended up being the only buffalo customers left before we had to cut everyone off entirely.”

In addition to Palace Market, Double 8 products were sold at Wild West Ferments, the Marshall Store, the Breaker’s Café in Stinson Beach, the Coast Café in Bolinas and a scattering of other shops and restaurants around the Bay Area. Those businesses will now serve soft serve made by Valley Ford Creamery, which sources its Jersey milk from Mr. Moreda’s brother’s dairy, located just a few minutes down Valley Ford Road.

Though it might lack the mystique and butterfat of buffalo milk—which can reach nine per cent—Jersey milk is naturally richer than most conventional dairy, with five to six percent butterfat, compared with roughly three to four percent in the milk of the ubiquitous Holstein cow. 

It is less of a niche product, but its producers insist that any variation in taste will be subtle. “If you saw the recipes side by side, they’re essentially the same,” Mr. Moreda said. “The only difference is we add a little cream to the jersey milk to match the fat. You’d have to be a complete connoisseur to know the difference.”

Mr. Zlot agrees. “I think that soft serve from Jersey milk will taste fabulous, frankly, but it just won’t have that moniker people have come to love,” he said. “It’s a shame, but, at the end of the day, if they close their eyes and put their mouth on the cone, they’re just going to love it.”

Not everyone is convinced. Robert Stephens, a bona fide Sonoma County foodie, said he could identify buffalo-milk soft serve even in a blind tasting. 

“The texture is unlike anything else,” he said. “You could tell the difference even if you had no taste buds. The texture, the weight, the mouthfeel—it’s like 10 times any other soft serve.” 

And although soft serve is usually considered lowbrow, Mr. Stephens said the buffalo-milk version was something else entirely. “It’s the foie gras of soft serve,” he said. “The French don’t eat it every day, but it’s a delicacy.”

At Wild West Ferments, where buffalo soft serve anchored a rotating menu of seasonal floats made with fermented fruit sodas, the offerings will continue with the Jersey-milk version. “The hardest thing is losing the name—it was the sexiest part, and it really drew people in,” co-owner Luke Regalbuto said. 

Mr. Stephens, for his part, was wistful for what he considers one of life’s great culinary pleasures. “The fact that Double 8 ever made that stuff is worthy of praise,” he said. “What is that phrase? ’Tis better to have tasted buffalo soft serve gelato and lost than never to have tasted it at all.”