When people describe their first encounters with natural wine, it can sound like a conversion experience — or like the euphoria of turning a corner and bumping into a wildly beautiful stranger. For the New York wine director Justin Chearno, what followed when he first dipped into a Lapierre Morgon, an unfiltered red, was an internal shift that changed the way he experienced his favorite drink. From then on, he says, natural wine “became my obsession.”

As is often the case with newfound zealotry, his quest became contagious and all-encompassing. Chearno is now one of the owners of the Four Horsemen, a bar in Brooklyn where natural wines are the main event. His vocabulary has become spiked with odd descriptors like ropiness, mousiness and brettanomyces. Even his wife can no longer drink conventional wine. “I can’t believe you did this to me,” she told him. Chearno has heard the same thing from his customers.

Conventional wines — those that we have drunk our entire lives, and that dominate the menus and shelves of restaurants and stores — can start to seem predictable after a dip into the funkier, cloudier, is-there-a-pasture-in-my-glass surprises of this category. There comes a surprise, too, when you learn what’s in a lot of conventional wines. To achieve the desired flavor, clarity, color and easy drinkability (so that a sauvignon blanc tastes the way a sauvignon blanc is traditionally supposed to, in other words), winemakers commonly add in sulfites, sugars, extra yeasts and fining agents that might be derived from egg whites, volcanic clay or fish bladders. None need to be listed on the bottle. “You can literally manipulate everything about a wine,” says Isabelle Legeron, the author of “Natural Wine” and the first French woman to earn the title of Master of Wine. Her mission, she adds, is to let the world know that most of what we drink is “grape juice and a bunch of other stuff.”