Pét-Nat is short for Pétillant-Naturel which is French for naturally sparkling. Hence, Pét-Nat are sparkling wines, often with a lighter fizziness than Champagne.
They are made using a simple method, the so-called méthode ancestral, where the young wine is bottled before the fermentation is finished. The residual sugar in the wine will continue to ferment in the bottle, causing carbon dioxide which gives the sparkling effect.
The leftover yeast cells, the lees, can be removed by disgorgement or left in the wine, which will cause a light haziness when the wine is shaken a bit.
