SO₂ is a very important wine preservative. However, there are several drawbacks associated with the use of SO₂ in wine. 

The aim of the Spanish work published on Biomolecules is to evaluate the effect of the partial substitution of SO₂ in the Tempranillo wine by a Mazuelo grape stem extract and by a commercial vine wood extract (Vinetan). The results were compared with a control sample (with no addition of any extract). After 12 months of storage in a bottle, total anthocyanin content, together with total polyphenol and flavonoid content were slightly higher for control wines than for those treated with extracts. These differences were of little relevance, as no differences in antioxidant activity were found between any of the wines at the end of the study. 

The sensory analysis revealed that the use of both extracts as partial substitutes of SO₂ could lead to wines with good organoleptic properties, similar or even better to the control ones.