A popular Southern drink in the early 20th century, buttermilk is once again being served as a stand-alone drink.

In accordance with local tradition, attendees of the annual Southern Foodways Alliance conference in Oxford, Miss., like to place a bottle of bourbon on William Faulkner’s grave. One morning during last October’s session, there was an unusual sight: a bottle of buttermilk.

“Well that’s because it’s great for a hangover!” Cheri Cruze said. She was there with her husband, Earl, and their daughter Colleen to receive the Keeper of the Flame Award for Cruze Farm buttermilk, made in Knoxville, Tenn.

That week, Earl received “the rock star treatment” for his cultured buttermilk, which remains a key ingredient in such totemic Southern dishes as biscuits and fried chicken. (Said treatment also stemmed from the video in which the smooth-skinned, twinkly-eyed 66-year-old Earl, who drinks up to a quart of buttermilk a day, deemed it “better than Viagra.”)

“If buttermilk is on the wane, you’d never know it talking to Earl Cruze,” said John T. Edge, the director of S.F.A. He describes Cruze as a “silver-tongued, buttermilk-drinking devil.”

Once a popular Southern drink, buttermilk had gradually been relegated to the ingredients column, starting in the 1940s. But with its tangy flavor, creamy consistency and golden flecks of butter, Cruze Farm’s buttermilk has the necessary charm for the artisanal generation.

“If you dare to do a side-by-side taste test, you’ll be blown away,” said the chef John Fleer, who found it at a local farmers’ market 10 years ago and incorporated it into the Foothills cuisine he was pioneering at Blackberry Farm, a luxurious restaurant and inn in Walland, Tenn. Fleer has showcased buttermilk in everything from panna cotta to cornbread soup, even whipping it with cream to give desserts “an acidic edge.” Fleer is figuring out how to get it to Cashiers, N.C., where he’ll open Canyon Kitchen at Lonesome Valley this summer. (The Cruzes deliver only within 90 miles.)

A fourth-generation dairyman, Cruze began bottling his own milk in 1981. He works his 575-acre Knoxville farm with his son, Glenn, 26, and daughters Colleen, 21, and Frances, 28. (Cheri describes her role as “the center of the Oreo cookie: I hold it together.”) He started making what Edge dubs the “antediluvian fluid” in the mid ’90s. “My daddy, he drank a lot of buttermilk,” said Cruze, dressed in his best Carhartt and plaid, as he crumbled cornbread into a glassful in his farmhouse. “My granddaddy sold it out of the back of a wagon. I thought it helped them, and I wanted to keep drinking it.”

There is no true definition of buttermilk, according to Anne Mendelson, the author of “Milk.” Originally it was the liquid that separated from churned butter. In warm climates, like the American South or India, it refers to sour milk, since unrefrigerated milk turns within hours. Today most buttermilk is made from milk to which cultures of lactic-acid bacteria are added. The Cruzes add a culture to their fresh, pasture-raised, hormone-free milk and mechanically churn it in 40 10-gallon batches.

Like its cousin yogurt, buttermilk has gastrointestinal benefits. “It’s grandma’s probiotic,” Cheri said. As to the health perks Earl touts, she’s fully on board: “He’s not a naturally happy, contented person,” she said with a chuckle. “But with buttermilk, he’s someone else. It calms him down, soothes his stomach, it makes him happy.” No wonder she won a “Why I Belong in Lake Wobegon” essay contest.

Buttermilk has culinary benefits as well, acting as leaven in baking, tenderizing meat and adding “a mysterious flavoring that just makes it better,” according to Cheri, who uses it in her mysteriously good poundcake.

Once, it seemed that their buttermilk-drinking clientele was dying, “but it’s better now than it was then,” said a surprised Earl. “This past year has been the most fun we’ve had.”

Working with his children has been part of it. “I hope to get them in shape to take over,” he said. “I prefer they do this over anything else. It’s been a great life for me.” Frances does the marketing, Glenn tends to the cattle and Colleen, a senior in agriculture science at the University of Tennessee, processes and delivers milk and maintains the farm blog, becoming the public face of Tennessee dairy’s next generation along the way.

“I’m really satisfied and fulfilled by the dairy business,” said the beatific Colleen, dressed in a knit minidress and knee-high boots, a colorful cross at her neck. (She credits buttermilk baths for her pearlescent skin.) Her approach to farming differs from her classmates’, but she’s unwavering. “They think you have to do a lot of what you’re doing to be successful,” she said “Times are changing, and I think the small man is slowly coming back, don’t you think?” Faulkner’s visitors would drink to that.