Pétillant naturel, also known as Pét nat is the oldest way of producing sparkling wines, the Méthode ancestrale. It's the most natural way to produce sparkling wines and a simple proces. The winemakers do not add any sugars or yeasts to the wine like they do with Champagne and Cava in the traditionel method. The grapes first ferment in a tank with their indigenous yeasts, but halfway the fermentation process the wine gets put in the bottles with a crown cork. Because of the leftover yeasts that turn sugar into alcohol and bubbles are formed in the bottle. Pétillant naturel, cloudy due to the yeast cells that are left over in the bottle, because just like all the natural wines, the wine is unfiltered. And often low in alcohol.