Effect of Winery Yeast Lees on Touriga Nacional Red Wine Color and Tannin Evolution

• Autores: Ana Rodrigues, Jorge Manuel Ricardo da Silva, Carlos Lucas, Olga Laureano
• Localización: American Journal of Enology and Viticulture, ISSN 0002-9254, Vol. 64, Nº 1, 2013, págs. 98-109
• Idioma: inglés
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• Dialnet Métricas: 1 Cita
• Resumen

  • Red w ine aging on lees is a w inemaking practice u sed to achieve more rounded a nd less astringent wines. In two different trials, external yeast lees were added to a red wine and their effects on wine color and tannin evolution during aging were studied. Results indicated that the addition of yeast lees did not affect color stabilization during t he studied period. Color compounds a nd condensed t annins were rapidly adsorbed to t he yeast lees at the beginning of the experiment. There was a retarding effect on proanthocyanidin polymerization reaction by the addition of yeast lees, leading to the maintenance of low and medium molecular weight tannins in solution. Two different interactions were observed: first, proanthocyanidin adsorption by the yeast lees, primarily ones with the highest polymerization degree, and second, the retarding of proanthocyanidin polymerization, likely by the mannoproteins released by yeast lees. The age of the yeast lees was a factor in mannoprotein release and its effect in wine