Pet Nat: Herstellung von Pet Nat

Although the precipitation of potassium bitartrate has no significant disadvantages in terms of sensory perception, tartaric stabilization is an essential process of wine production to achieve a more attractive product for customers. Especially for “Pét Nat”, which means “Petillant Naturel” and is an increasingly popular product, tartaric stabilization is important to reduce the risk of the reluctantly seen phenomenon of gushing. As “Pét Nats” are gaining increasing importance, the main focus was laid on tartrate crystal precipitation. 

In the course of this work eight production variants of Pét Nat were carried out with a Chardonnay must. One batch was cross-flow-filtered to remove as many turbidity-causing substances as possible. Two other variants of Pét Nats were produced, without treating them with stabilization methods. One of these was fermented spontaneously, the other was fermented by means of cultured yeast. In another case one must was cooled down to 4° C. Two further batches of the must were treated by contact tartrate (vaccination crystals) and potassium polyaspartate to prevent big amounts of potassium bitartrate at the bottom of the bottles. Finally, the last two variants were fermented and stored in different bottle positions.

By means of analytic procedures it could be detected that the Pét Nat, which was fermented spontaneously and the Pét Nat, which was cross-flow-filtered contain the least amount of potassium. Because of this, one may assume that for these variants most potassium bitartrate precipitated before the disgorgement. Whereas the variant, which was inoculated by yeast and the variant, which was treated by contact tartrate contain noticeably higher amounts of potassium. The highest amounts were detected at the Pét Nat which was treated by potassium polyaspartate and which was cooled down to 4° C for ten days. The higher amounts of these variants revealed that less potassium precipitated and thus potassium bitartrate was kept in solution.

Based on visual analyses it could be detected that the Pét Nat, which was cross-flow-filtered and the Pét Nat, which was stabilized via cooling contain smaller amounts of wine lees than the Pét Nats which were inoculated by yeast, treated by contact tartrate and treated by potassium polyaspartate. The highest amounts were observed in the Pét Nat, which was fermented spontaneously. Moreover, these variant is the most hazy and the Pét Nat, which was cross-flow-filtered the least hazy one.