The effect of fine lees as a reducing agent in sur lie wines, aged with various sulphur dioxide concentrations

Abstract

During the ageing in barrels, the contact with the fi ne lees triggers several processes in wine. Lees has a reductive effect by absorbing dissolved oxygen and reducing the amount, which will remain in the wine. At present, minimizing the addition of sulphur dioxide is the trend in all viticultural areas. In this study, the effect of various sulphur dioxide levels was monitored in presence of the lees to determine which dose is appropriate to provide the protection of susceptible white wine against oxidation.Without SO 2 protection, the rH and redox potential changed slightly, so the level of dissolved oxygen seemed to be controlled during the ageing period by the lees, though the antioxidant effect of lees in itself was not appropriate to protect the polyphenol content from chemical oxidation, which led to considerable browning. With the addition of a lower amount of SO 2 -40 mg l -1 , the lees is already able to protect the white wine samples in all aspects. Keywords: sur lie, fi ne lees, reducing agent, polyphenolic compoundsThe sur lie method is a special wine making technology, where the contact between the new wine and the fi ne lees can be taken advantage of. It has a special momentum, namely the battonage, when the wine is stirred periodically in the barrels. This technology originates from France, but nowadays wine makers -in all viticultural areas -use it to widen the white wine assortment. The contact with the fi ne lees plays an important role in traditional champagne production, too (FIA et al., 2016). From the practical point of view, the robust/full bodied wine, which is properly rich in alcohol and acids, is fi t for ageing on lees in oak barrels.The composition of fi ne lees is varying. It contains mainly yeast cells, and in much lower amount, tartaric acid and other organic and inorganic matter. The autolysis is known as a slow process that occurs during the wine ageing period (between 12 to 18 months). So the intracellular compounds, enzymes, plasma membrane, etc., are released just approximately after one year (LAVIGNE et al., 2007;PÉREZ-SERRADILLA & LUQUE DE CASTRO, 2008).It was shown that the resuspension of the lees by stirring (battonage) during the aging period signifi cantly increased the macromolecular extract of the wine (especially mannoproteins, proteins) beside saturated fatty acids and glutathione. The yeast strain, the turbidity of juice during the fermentation, the contact time and temperature also have effects on the migration of the polysaccharides (PÉREZ-SERRADILLA & LUQUE DE CASTRO, 2008).

Chemical Constituents of Fruit Wines as Descriptors of their Nutritional, Sensorial and Health-Related Properties

“…One of the challenges for scientists and winemakers who are striving to meet today's consumer demands for SO 2 -free high-quality wines is the application of new technologies to replace the use of SO 2 [171]. The alternatives to SO 2 investigated so far include treatments with lysozyme, dimethyl dicarbonate (DMDC), the addition of reduced glutathione (up to 20 mg/L) and the addition of commercial oenological tannins [170,[172][173][174][175][176].…”

The effect of black rot on grape berry composition

“…Phenolic compounds are responsible for the bitter taste, contracting mouthfeel, and browning of wines. Flavonoids have reducing and antioxidant properties and are often polymerised (Nagy et al, 2017).…”