Abstract Tohru OkudaGuangxian LiangMasaru GozuEri InoueFumie Saito-WatanabeMasashi Hisamoto

Understanding the Composition of White Wine Lees during Vinification

Tohru Okuda,* Guangxian Liang, Masaru Gozu, Eri Inoue, Fumie Saito-Watanabe, and Masashi Hisamoto
*University of Yamanashi, 1-13-1 Kitashin, Kofu, Yamanashi, 400-0005, Japan (okuda@yamanashi.ac.jp)

Although racking is crucial for making good-quality wines, little is known about wine lees. In this study, we analyzed the composition of lees obtained from zero racking (juice settling), first racking (immediately after alcoholic fermentation), and second racking (before bottling) during vinification in Chardonnay white winemaking. Each of the lees was divided into two to three layers by centrifugation. Proteins, phenolics, carbohydrates, and organic acids in each layer were analyzed. The total amounts of these four recovered components ranged from 82.6 to 124%. Compositional diversity was observed among different lees layers from different racking steps. Insoluble polysaccharides from grape were the major constituents in the upper and middle lees layers from zero racking. The high proportions of proteins and mannose present in the upper and middle layers from the first racking and the upper layer from the second racking indicated that yeast cells produced during alcoholic fermentation mostly settled in those layers. Large amounts of tartrate were deposited in the lower lees layer from all racking steps, particularly the first and second racking, which was mainly composed of tartrate. The content of phenolic compounds in the entire lees was low. SDS-PAGE showed that the lees contained different proteins than wine.

Funding Support: University of Yamanashi