(WSJ) - PÉT-NAT MUST BE one of the cutest monikers in the wine world today. The whimsical nickname for pétillant-naturel, a slightly sparkling natural wine, also happens to capture its character best. Softly effervescent, sometimes quite frothy and ranging in style from dry to sweet, pét-nat can be as much fun to drink as it is to pronounce.

The word “fun” came up over and over again when I asked fans and producers why they liked pét-nat so much. I haven’t heard that adjective very often in wine conversations, but it’s cropped up with greater frequency over the past several years—usually during discussions about pét-nat, which has been showing up on more wine lists and store shelves.

Pét-nat is actually one of the oldest types of sparkling wine in the world, said even to predate its more serious cousin, Champagne, which was created in the 17th century. It’s also easier and cheaper to make. Pét-nat is produced by bottling the wine before it has completed fermentation. Unlike Champagne and other bubbly made using méthode traditionnelle, no sugars or yeast are added. Instead, the bubbles are formed naturally as the sugar that remains in the bottle from the grapes acts upon the wild yeast, producing carbon dioxide. Another difference: Whereas Champagnes are often blends of different wines from several vintages, pét-nat is created from a single vintage, often just a few months after harvest—making it, as fans say, a sparkling wine that actually tastes like a grape.

Though pét-nat is easier to produce than Champagne, it is by no means a simple proposition. Sediment, in particular, can be an issue. Left in the bottle, these solids can continue to ferment—a potentially explosive situation. Zev Rovine, of New York importer Zev Rovine Selections, said bottles that haven’t had sediment removed through a process known as disgorgement can “shoot tons of wine out of the bottle” when they are opened, exploding as the pressure from the carbon dioxide builds up.

Disgorging the wine also helps ensure that it’s clean, as bacteria can develop, affecting the wine’s taste and smell. Lise and Bertrand Jousset, a wife-and-husband winemaking team in France’s Loire Valley known for their pét-nats, said they began disgorging their wines because they thought the undisgorged bottles tasted “funny.” Sommelier Pascaline Lepeltier, of New York’s Rouge Tomate restaurant, said the industry term for such bacteria-ridden wines is “pét-nasty.”