First Uses of Italian Natural Zeolitites In the Proteic Stabilization Process of Autoctonous White Wines of Campanian Region (Fiano and Falangina cultivars)

A very frequent cause of turbidity and formation of organic deposits in white wines is the occurrence of thermolabile and thermostable proteins colloidal suspensions which precipitate in time, especially in summertime and during the storage and transport. To mitigate this risk wine producers use organic and inorganic stabilizers and clarifiers. Generally, the best known treatment, recognized also by the International Organisation of Vine and Wine (N° SIN : 558 – Resolution OENO 11/2003) foresees the use of bentonite with a montmorillonite content not lower than 80%. The present paper aims at evaluating the use of two high zeolite grade Italian volcanoclastites such as the Neapolitan Yellow Tuff (NYT) and the yellow facies of the Campanian Ignimbrite (ICFG), in the treatment of two peculiar white wines of the Campanian region (Southern Italy): Falanghina and Fiano.

Granulates were produced starting from tuff blocks as provided by quarries. Some grain size fractions have been prepared to investigate which of them had the highest zeolite content (phillipsite + cabasite + analcime). A 2-5 mm grain size fraction was chosen for NYT and a 5-10 mm for ICFG. Two campanian monocultivar white wines were used for the test: the Avellino Fiano, 2007 grape harvest and the Falanghina, 2006 grape harvest.

Even though the experimental conditions were substantially different from those of commercial wine production, it was evidenced by turbidimetric analysis that the use of 7-8 g/l zeolitic mixture enables the proteic stabilization. A significant decrease of potassium ion after the treatment with the zeolite-rich powder, which improves the tartaric stability a serious problem in all the wine productions, was also recorded.