Pétillant Naturel (nicknamed Pét-Nat) is a type of sparkling wine made in the méthode ancestrale method traditionally used in France, which has caught on in California in recent years.
Grapes are pressed and undergo primary fermenation in cold vats until the alcohol reaches about 6º brix. After a light filtration that leaves much of the active yeast but removes some of the lees from the unfinished wine, it is bottled and topped with a crown cap, and continues its fermentation in the bottle, capturing the carbon dioxide that is naturally released. There is no dosage or addition of yeast before the second bubble-producing fermentation as is done in méthode champenoise used in Champagne.
Since Pét-Nats are produced only with the natural sugar of the grapes and ambient yeasts, they are a pure reflection of their grape variety and terroir.
The resultant wines are easy to like, often with softer bubbles than Champagne, and part of the fun is that since they are unfined and unfiltered, the wines offer subtle variations in flavor from bottle to bottle. The wines are lower in alcohol than traditional sparkling wine as well.
California producers offering petulant naturel wines include Onward Wines, Birichino, Donkey & Goat Winery, and Salinia Wine Company. Currently, there is very little of this sparkling wine in distribution, but check with your favorite retailer and go online to the websites of the wineries mentioned to obtain the wines. These are fantastic, inexpensive wines to stock up on for summer!