The composition of N containing compounds, including amino acid concn., of wines kept on fine lees changes as a result of the autolysis of yeasts. Previous experiments have proven that yeasts are able to reduce the polyphenolic composition of wines. In this study the change of polyphenols content of Chardonnay wines kept on the lees was analysed. In addition the quantity of tyrosol, required for the forming of simple phenols, was examined. The results proved that yeasts reduced the quantity of polyphenols. In addition, due to the increased amino acid concn., yeasts reduced the quantity of tyrosol that is derived from tyrosine. (We recommend that you consult the full text of this article)