Winemaking from Koshu Variety by thesur lieMethod: Change in the Content of Nitrogen Compounds

Abstract

Newly fermented wine from the Koshu, the traditional white variety in Japan, was stored in contact with the lees for several months, and the changes in the content of nitrogen compounds were investigated. The total nitrogen content in the wine rapidly increased in the first month of storage, while the content of proteins decreased rapidly during the same period. As aging proceeded, a slow increase in the content of total nitrogen and a slow decrease in that of proteins were noted. Amino acids, particularly aspartic acid, histidine, and lysine, significantly increased until the fourth month. The increase in the content of total nitrogen seemed to be ascribed to release of intracellular amino acids from sedimented yeast cells. The increase of total nitrogen and amino acid content may contribute to the taste and flavor of the wines produced by the so-called <i>sur lie</i> method.