¿En qué consiste el proceso de fermentación del vino?

Without fermentation there is no wine. It is the stage in which the must is transformed and begins to define its character. We explain, without unnecessary jargon, what really happens during those decisive days.

What fermentation is

Fermentation is the moment when grape juice, the must, turns into wine. In simple terms, yeasts consume the grape's natural sugars and transform them into alcohol and carbon dioxide. It is a natural process that humans have been guiding and refining for thousands of years.

Although it may seem automatic, every detail counts. The temperature, the type of vat or the moment when the process is stopped directly influence the wine that will end up in the bottle.

The role of yeasts

Yeasts are the true protagonists. They may already be naturally present on the grape's skin and in the winery, or they may be added in selected form to better steer the outcome. Both options have their supporters, and many wineries choose according to the style they are after.

• They transform the sugar of the must into alcohol.
• They generate aromas and nuances that define the wine's profile.
• They work as long as there is sugar available and the right conditions.

The factors that change everything

Fermentation does not happen in a vacuum. There are several elements the winemaker keeps a close eye on:

• Temperature: cold slows the process and preserves fresh aromas; heat speeds it up and brings another kind of expression.
• The contact time with skins and pulp, key in reds for extracting colour and structure.
• The type of vessel, whether steel, concrete or wood, which leaves its mark on the result.

Adjusting these parameters is where the craft shows. Two wineries working with the same grape can obtain very different wines depending on how they manage this stage.

From harvest to glass

Fermentation begins shortly after the harvest, when the grapes arrive at the winery at their best. From there begins work that continues throughout the ageing, but whose foundations are laid precisely in these first days.

Understanding this stage helps us appreciate better what we drink. And there is no better way to grasp it than to see it up close: many wineries explain the process during their tours, especially at harvest time.

Seeing it with your own eyes

If your curiosity has been sparked, a guided tour is the most direct way to discover how a wine is born. You can check our guide on how to visit a winery and choose the ideal moment to experience fermentation first-hand.

In the end, every glass conceals a small everyday miracle. Knowing how it begins makes it all the more enjoyable.