In Praise of Yeast

The Fascinating Role of Yeast in Winemaking

In this episode of After Wine School, host Keith Wallace, joined by fermentation expert Alana Zerbe, delves deep into the critical role yeast plays in winemaking. They explore why wines have distinct smells, how yeast converts grape sugars into alcohol, and the influence yeast has on flavors, mouthfeel, and terroir. The discussion covers the complexity of Saccharomyces cerevisiae, native yeasts, and the impact of fermentation temperatures. They also discuss the nuances of wild yeast fermentations, stuck fermentations, and the presence of Brettanomyces. The episode concludes with a lightning round exploring the yeast characteristics of various wine styles. Wine lovers and aspiring winemakers will gain a thorough understanding of the science behind their favorite wines.

00:00 Introduction 00:43 The Role of Yeast in Wine Making 01:20 Saccharomyces: The Workhorse Yeast 02:02 Non-Saccharomyces Yeasts 02:36 Yeast and Wine Complexity 03:30 Terroir and Yeast 04:41 Sherry and Vin Jaune 05:50 Champagne 06:49 Temperature's Impact on Fermentation 19:08 Wild Yeast 19:35 The Role of Native Yeast in Winemaking 26:07 Brettanomyces: The Double-Edged Sword 28:51 Lightning Round 31:00 Final Thoughts