Critical factors for the evolution of long-lived white wines

Franco Battistutta & Ilaria Picco, University of Udine

The evolution of world markets has led to an evolution of the concept of stability and longevity. All wines must ensure high quality standards for several years so longevity is not just a goal for a small niche of great wines, and stability is no longer simply tartaric or protein stability. These concepts should be extended to almost all white wines for which good sensory evolution is required for several years.

With this in mind, it is useful to overview the main factors of stability and instability and the points in the chain where action can be taken to affect wine evolution. The main chemisms depend on the interaction between phenolic fraction, aromatic fraction, metals and the management of Redox potential.

Starting from the prefermentative moment, the parameters of choice are maceration, oxidizing or reducing environment, use of adjuvants or additives; each choice will condition the composition of the must and the evolution of the product.

The fermentation phase leads to a normalization of the redox potential but confronts us with a number of other issues that can lead to the onset of reduction odors: action must be preventive or modulated correction with lees, yeast derivatives, wood or tannins.

The aging and pre-bottling stages are aimed at achieving an overall balance of the wine; here again lees, wood, yeast derivatives, tannins and oxygen play a key role in the evolution and fate of our wine.

Next, we must not forget temperature: from mashing to glass it is often underestimated in the management of wine evolution.

Longevity of white wines: the key role of yeast derivatives and tannins

Maria Manara, R&S DAL CIN Gildo spa

White wines are definitely a category in demand in the market, and the indispensable requirements are aromatic intensity, freshness, and cleanliness. These requirements must be maintained throughout the life of the wine, until final consumption. The quest for organoleptic longevity is accompanied by the demand for wholesomeness and thus, for example, efforts to reduce the sulfite content in finished wines.

Simultaneously meeting these seemingly conflicting goals requires planning that starts with grape harvesting and continues with must treatment, management of alcoholic fermentation to bottling.

Yeast derivatives and tannins, singly or in combination, are good allies in achieving the goal.

Yeast derivatives are among the most interesting tools available to the winemaker to ensure the proper evolution of white wines. Depending on the yeast of origin and the production systems adopted, derivatives with different characteristics can be obtained and thus exploited to achieve different objectives. Harmony Vitality, a yeast derivative to be used during aging and storage, thanks to the presence of GSH and reducing peptides protects the wine from oxidation, removes some sulfur compounds and potentially oxidizable polyphenols, and ensures wine longevity by preventing browning and pinking phenomena.

Tannins represent a second family of effective and diverse tools; their use enables the achievement of such peculiar objectives as protection from oxygen, capture of volatile thiols, chelation of metals, while respecting or improving the taste balance of wine.

The application of innovative analytical techniques, including cyclic voltammetry, has made it possible to identify the correct tannin to use in the different stages of wine processing, from harvesting to aging to bottling. With Top Tan AR, Infinity Vert and Tanniblanc, action can be taken both during aging and in preparing the wine for bottling.

Many observations from our studies on the longevity of white wines are also reflected in the production of rosé wines. We have specific work in progress on this delicate type of wine, with particular reference to the preservation of color hue.