When people think of wine, they often picture rolling vineyards, sun-ripened grapes, and the pop of a cork. But one of the most essential elements in winemaking is microscopic and invisible to the naked eye: yeast. Without it, wine simply wouldn’t exist. So what exactly is the relationship between yeast and wine? Below we will demystify the role of yeast in winemaking, explore the different types used in fermentation, and explain how winemakers make key decisions that influence everything from texture to flavour.
Yeast is a single-celled fungus that has been part of winemaking for thousands of years. The most important species for wine is Saccharomyces cerevisiae, prized for its efficiency in converting grape sugar into alcohol.
In natural environments, yeast lives on the skins of grapes, in the winery, and even in the air. Once in contact with grape juice, yeast begins a powerful process: yeast wine fermentation. But there’s more to this tiny organism than just turning sugar into alcohol.
Put simply, yeast and wine go hand-in-hand. During yeast wine fermentation, yeast consumes the sugars in grape juice and produces:
– Alcohol
– Carbon dioxide
– Heat
– A wide range of flavour compounds (known as esters and phenols)
This biochemical reaction is what transforms sweet juice into stable, complex wine. Beyond alcohol, different yeast strains also influence mouthfeel, aroma, and texture—making yeast not just a fermenter, but a flavour-maker.
When it comes to yeast in winemaking, winemakers typically choose between two paths: ambient yeast or cultured yeast. Each brings distinct advantages—and challenges—to the table.
Wild fermentation uses the natural yeasts found on grape skins and in the winery environment. This is often called ‘spontaneous fermentation’.
Pros:
Cons:
Cultured yeasts are laboratory-selected strains of Saccharomyces cerevisiae, developed for specific wine styles and fermentation conditions.
Pros:
Cons:
Yeast doesn’t just create alcohol—it builds a wine’s identity. Different strains produce different aromatic compounds, influencing everything from tropical fruit notes in a Sauvignon Blanc to the rich, biscuity character of sparkling wine.
Some yeast strains enhance:
This is why yeast selection is an artistic choice, as much as a technical one. Even subtle differences in yeast wine fermentation can lead to vastly different outcomes in the glass.
They’re common queries: 'Can I make wine without yeast?' or 'Can wine be made without yeast?' The answer is: no—not really.
All wine fermentation requires yeast, whether it’s naturally occurring or added by the winemaker. If no yeast is introduced, wild strains from the grapes or environment will eventually begin fermentation. So while you can skip adding yeast, you can’t make wine without it. That’s why even natural winemakers—who often avoid added yeasts—still rely on the ambient microbes present in their vineyards and cellars.
Yeast selection is a thoughtful process that balances science, style, and philosophy. Some of the key factors influencing this decision include:
At De Bortoli, we approach yeast in wine-making with both precision and creativity, choosing strains that enhance varietal character while supporting a clean, successful fermentation.
Every bottle of De Bortoli wine is the result of careful choices—from vineyard to fermentation. Our winemakers thoughtfully select the right yeast (or let nature take the lead) to craft wines that express both place and purpose.
Whether you’re sipping our The Estate Vineyard Chardonnay or a bottle of Noble One Botrytis Semillon, know that the role of yeast in shaping its identity is anything but invisible.
Discover our collection and taste a true balance of science and soul in every glass.
You can avoid adding commercial yeast, but fermentation will still occur via ambient yeasts found on the grape skins and in the winery. So while it’s possible to skip additions, yeast and wine are inseparable.
Most commercial wines are filtered or fined after fermentation, removing most yeast cells. However, trace amounts may remain—especially in unfiltered or natural wines, which can appear cloudy or develop sediment.
Yes. Yeast converts sugar into alcohol. The strain of yeast and the initial sugar level in the grape juice will determine the final alcohol content. Some yeasts are more efficient or can tolerate higher alcohol levels than others.
True yeast allergies are rare, but some people may experience sensitivities to residual yeast or its byproducts. If you're sensitive, unfiltered wines or those made with wild yeast may be more likely to trigger a reaction.
Fermentation typically lasts 7–14 days, depending on grape type, temperature, and yeast used. Cooler fermentations for whites may take longer, while reds fermented at warmer temperatures often finish faster.
This is called a stuck fermentation, which can result in a wine that’s too sweet or unstable. Winemakers may attempt to restart it by adjusting temperature, and nutrients, or even adding a fresh yeast culture.
Most natural wines rely on wild yeast fermentation as part of a low-intervention approach. This contributes to their distinct, sometimes unpredictable, profiles and is often a point of pride among natural winemakers.
Not at all. Cultured yeast provides consistency, safety, and stylistic control, especially important in large-scale winemaking. Many premium wines use cultured yeast with excellent results—it’s about the right tool for the job.
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