Pet-Nat is French for petillant-naturelle, which translates as "naturally sparkling". Put simply, before the first fermentation is complete, we bottle the wine and let the process resolve. The result is a bubbly and sparkling wine. Unlike the classical method, which we see with sparkling wines, Pet-Nats have the entire sediment in the bottle, which is why they are cloudy.
Pet-Nats are best served cold.