Natural Wines are those that have the minimum posible intervention of man.Sulfites are not added. Natural yeasts are used and the wine is bottled unfiltered. Fermentation in tanks. When the natural sugars in the wine have a value of 23 grams per liter, it is bottled and the final sparkling wine is left with 9 grams of sugar. The wine continue to ferment inside the bottle up to the indicated pressure. The sugar in sparkling wine and it ́s pressure are obtained naturally. The lees remain in contact with the wine, which is expressed in its turbidity. Selected native yeasts. Pet – Nat.