I drank my first bottle of pétillant-naturel—more affectionately known as “pét-nat”—at least a couple years before I ever heard it called by that name. A friend offered me a glass of what she described only as “this really weird sparkling natural wine.” Sealed under a crown cap and cloudy, with an unusually soft effervescence, the wine turned out to be Andrea Calek’s “Blonde,” one of the earliest examples of its kind to gain stateside attention. “True,” I remember thinking, “this is weird.”

Today, pétillant-naturel is everywhere. Given how readily it lends itself as fodder for trend pieces, the style has attracted the attention of writers and bloggers. Just about every article on the subject makes a point of describing the méthode ancestrale, or “ancestral method” whereby pét-nat derives its fizz. As a form of fermentation, the technique pre-dates the so-called Champagne method by a couple centuries, at least in those areas of France—like Gaillac, Limoux and Bugey—where it has historically been practiced. Unlike the Champagne method, which enacts a secondary fermentation by adding sugar and yeast, the ancestral method allows the initial fermentation to finish in bottle without any additives, imparting a gentle carbonation by trapping carbon dioxide.

Technical details aside, efforts to pin down the style’s history have mostly been confusing. Recent articles have dubbed it “Champagne’s hip younger sister,” “the newest insider sparkling wine,” “pre-technological,” “a singular experience of terroir” and “sort of accidental, a little dangerous… and very much in vogue among the young Californian eonorati.” Low in alcohol, unfiltered and hazy, it’s often described—for better or worse—as an earthier, funkier, more “honest” or “authentic” breed of bubbly, which supposedly references some earlier (it’s never clear which!) period of France’s winemaking past.

One is left with the curious impression that pét-nat represents two contradictory things: on the one hand, it’s the latest hipster-approved wine trend—the kind of effortlessly drinkable stuff designed to be knocked back with abandon. And yet, on the other, it’s designed to be some sort of old-school vinous throwback steeped in tradition.

Maybe it’s just cool in the same way that so many iterations of pre-industrial nostalgia (home-pickling, reclaimed barnwood, etc.) have become cool. Regardless, the fundamental question remains: What is pét-nat, really? What distinguishes it from the various ancestral method wines that have traditionally been produced in France? Is it just a repackaged name for an old concept, or is it something new?

Here’s where a little historical knowledge comes in handy. In most regions with established ancestral method traditions—like Limoux, for instance, which historians credit for inventing the word’s first sparkling wine in 1531—the technique was a simple byproduct of the seasons. Fermentation would continue until the onset of winter, when the cold would put the wine to sleep. Come spring, the warm weather would fire up the fermentation again, creating a naturally bubbly wine.

So much of the category’s appeal involves the whimsical, almost subversive way it re-casts an ancient style as the quintessential party wine.

Many of today’s ancestral method wines undergo a technological approximation of this process through temperature control, artificially halting fermentation in the tank via refrigeration. After several weeks, the half-fermented juice is then bottled and the fermentation resumes. Pét-nat, on the other hand, almost always goes straight from tank to bottle—an uninterrupted continuation of the primary fermentation.

Aesthetic distinctions come into play as well, particularly concerning disgorgement. Unlike many ancestral method wines, which are disgorged in the interest of creating a more stable commercial product, pét-nat is almost always bottled with the deposit of dead yeast intact: hence the style’s signature cloudiness. This also translates to pét-nat’s choice of closure: crown cap—like cider or farmhouse ale—as opposed to a foil-covered, caged cork.

According to Jules Dressner of Louis/Dressner Selections—the influential natural wine importer responsible for bringing many of the first pétillant-naturel wines to U.S. shores—the fundamental difference isn’t about the technical process at all, but a question of attitude.

“If you look at the regions where the ancestral method has historical roots, the producers are working within a specific tradition, which they take very seriously,” he says. “It’s the main product, and they’re trying to be precise. Pét-nat is supposed to be delicious, sure, but for someone like [natural winemaker] René Mosse, it’s really more of a fun, experimental side project than a complex wine of terroir.”

All considered, then, pét-nat is best understood as a contemporary sub-category of the méthode ancestrale that emerged in France’s Loire valley as recently as the 1990s. During these early days of the natural wine movement, progressive winemakers like Thierry Puzelat and the late Christian Chaussard were beginning to experiment with a new philosophy of organic viticulture and minimum intervention in the cellar, often with unpredictable results. As Dressner explains, pét-nat’s genesis (like so many great discoveries) can be ascribed to a happy accident.

“Back then, Christian [Chaussard] had an estate in Vouvray,” he says. “He bottled one of his Vouvrays, which contained some residual sugar—it was probably a demi-sec—and it accidentally started re-fermenting. At first, he thought it was ruined, but he tasted it and decided he liked it. I’m guessing that he did some insightful research and realized that this was an actual technique that was done in the past, so he started doing it intentionally.”

His friend and colleague Thierry Puzelat fills in the final chapters. “The true story… is that [Chaussard] was the first to use the phrase ‘pét-nat’ at the end of the 1990s. We all adopted this term, which is both concise and clear. Now it has passed into the everyday language of the viticultural world.”

Thus, the invention of pét-nat as we know it—if it’s fair to say it was “invented” at all. As Dressner points out, “it’s more like Chaussard reclaimed the style, just like [fellow natural winemakers] Marcel Lapierre and Pierre Overnoy reclaimed the style of their fathers and grandfathers.”

As with any effort to revive tradition, however, there is rarely a seamless continuity between past and present. It is ironic that pétillant-naturel emerged in the Loire, of all places—a region that hasn’t historically been associated with ancestral method winemaking.

In fact, as Leo A. Loubère explains in The Red & the White: A History of Wine in France and Italy in the Nineteenth Century, ancestral method wines can claim no more than an erratic legacy in the Loire. “Sparkling Vouvray did not appear regularly because it was not made consciously until about 1840,” he writes. With the eventual “control and regularization of this [vinification] process, learned from the champagne-makers,” ancestral method wines eventually gave way to the Champagne-method sparklers that still dominate there.

The ambiguity surrounding its ancestors in the region makes one wonder whether, ultimately, pétillant-naturel revolves around an idea of tradition, rather than any specific tradition itself.

This tension is inscribed in the category’s outlier status within the hierarchy of French wine law. While many ancestral method wines are guided by local appellation rules, the majority of pét-nat is declassified as basic Vin de France. In 2007, however, inspired by pét-nat’s growing popularity, the region of Montlouis-sur-Loire approved the creation of a new appellation called “pétillant originel” (the word “natural” is banned from French wine labels). Leaving aside the question of how “original” the wine might be, the laws governing its production—which include nine months of lees aging and mandatory disgorgement—highlight the irony of establishing an AOC around a style whose very nature resists regulation.

In the final verdict, beyond any regional ties, the category acquires its true identity under the banner of natural wine, whose values—irreverent, playful and unorthodox—it embodies in a very visceral way. Striving for rawness, it rejects the standardization of conventional sparkling wine in favor of something unfiltered, unadulterated and identified, however loosely, with the past. This artisanal impulse, which remains inseparable from the natural wine movement as a whole, actually speaks to a very modern form of longing—not for the past, per se, but for our collective fantasy of it.

This may be lofty talk for a wine you’d more likely chug from a mason jar at a barbecue than hold up to the light of serious philosophical scrutiny. But so much of the category’s appeal involves the whimsical, almost subversive way it re-casts an ancient style as the quintessential party wine. As Jules Dressner puts it: “You have to remember, these guys in the Loire are all buddies. The whole point is to make a fun wine to party with and drink with friends.”

Given its social nature, it should come as no surprise to see how virally pétillant-naturel has spread beyond France to parts of Italy, California—even Long Island. “Traditional” or not, it has evolved into a living tradition of its own, defined not along national or regional lines, but those of a community—even if that community gathering happens to take place around a backyard grill in Brooklyn.