For many years, a group of California winemakers have been practicing a technique known as “indigenous yeast” fermentation and making consistently excellent wine.
Why, all of a sudden, has this technique become a buzzword in the wine press and why have other winemakers recently begun experimenting with this technique? Enology International recently tackled that question.
Alan Tenscher, Senior Winemaker at Franciscan Vineyards, commented, “I see a trend toward a more natural way of making wine which starts in the vineyard with organic grape growing and extends to minimal handling of the wine. The use of wild yeast, from one perspective, puts one in that same camp. But on the other hand, there is a group of winemakers out there who are looking for any technique that will help them improve wine quality. The use of wild yeast is a tool to create complexity.”
The trend Tenscher observes has been popularized by influential wine critics who are proponents of wines made with more natural, less interventionist techniques. Indigenous yeast fermentations fall into this category because the vineyard’s native yeast start the fermentation naturally in contrast to the common California, and in recent years, European, practice of adding yeast to start the fermentation.
Fermentation is a vitally important stage in winemaking. The yeast not only converts sugar to alcohol, but also produces esters and other compounds which contribute to the wine’s fruit aromas. Extraction of flavor and color from the grape skins (for red wines) also occurs during fermentation.
Some yeast produces a heavier sediment which settles more quickly after fermentation, making racking and clarification easier. For smaller producers, varying the yeast strain as well as the temperature and duration (maceration) of fermentation can enhance the wine’s aromatic and flavor characteristics.
Wild yeast is not the secret, indispensable answer to making great wine. Rather, it is a piece of the puzzle — one in a number of ways to develop complexity in wines. This quality factor, coupled with the fact that the majority of winemakers feel these methods make their craft more interesting and challenging, assures that the use of wild yeast will continue to grow in the production of premium wines.
By matching the right grape varieties to the right growing regions, winemakers will be working with high acid, low pH fruit, reducing the risks of wild yeast fermentations.
