Spontaneous Fermentation

Spontaneous Fermentation in Winemaking

Spontaneous fermentation (also called wild fermentation) is a natural fermentation process where winemakers rely on indigenous (wild) yeasts from the vineyard, winery, and grape skins instead of adding commercial yeast strains. This method is widely used in natural, biodynamic, and some traditional winemaking styles to create wines with complexity, terroir-driven characteristics, and unique flavors.

How Does Spontaneous Fermentation Work?

1. Crushed grapes (must) are left to ferment naturally – No commercial yeast is added.
2. Wild yeasts from the environment start the fermentation – These yeasts come from grape skins, the vineyard, and the winery.
3. Multiple yeast strains take over in stages – Early yeasts might start the process, but stronger strains (Saccharomyces cerevisiae) usually finish it.
4. Slower fermentation process – Can be less predictable and take longer than controlled fermentation.
5. More complex and varied flavors develop – Yeast activity influences aromas, mouthfeel, and structure.

Why Use Spontaneous Fermentation?

• Terroir Expression – Reflects the natural environment, giving each vintage unique characteristics.
• Greater Complexity – Wild yeasts create more nuanced and layered flavors.
• No Additives – Used in natural and biodynamic winemaking for a more authentic approach.
• Unique Aromatics – Can develop funky, earthy, floral, or mineral notes.