What happens when the wine has been placed on the yeast

Yeast is crucial in winemaking as it plays a significant role in fermentation. Fermentation is a natural process where consumes sugar and converts it into alcohol. The process starts when the grapes are crushed, releasing their naturally occurring sugars. When the wine has been placed on the yeast, several essential transformations take place, ultimately shaping the flavor, aroma, and overall characteristics of the final product.

Once the grapes are crushed, the grape juice, also known as “must,” is typically exposed to yeast. These yeasts, known as Saccharomyces cerevisiae, can be naturally occurring in the vineyard or added artificially by winemakers. When yeast is introduced into the must, it consumes the sugars and converts them into alcohol, carbon dioxide, and heat. This process is called alcoholic fermentation.

During alcoholic fermentation, the yeast cells break down the sugars into alcohol, releasing carbon dioxide as a byproduct. This carbon dioxide can be trapped within the wine or allowed to escape through a vent, depending on the winemaker’s goals. The heat generated during fermentation can also affect the rate of fermentation and the overall characteristics of the wine.

As the yeast consumes the sugar, it multiplies and produces more yeast cells. This multiplication contributes to the fermentation process, allowing the alcohol content to rise. The yeast cells also produce various compounds that impact the final flavor and aroma of the wine. For example, some yeast strains produce fruity esters that give the wine a characteristic aroma. Others may produce sulfur compounds that contribute to the wine’s overall complexity.

When the wine has been placed on the yeast, it undergoes a series of chemical and enzymatic reactions. These reactions can result in the formation of new compounds, such as volatile acids, aldehydes, and phenols. These compounds can contribute to the wine’s flavor profile, adding complexity and depth.

The duration of yeast contact with the wine can also influence its characteristics. Some winemakers prefer to allow the wine to remain on the yeast, a process known as “lees aging.” During this period, the dead yeast cells settle at the bottom of the fermentation vessel, commonly referred to as the lees. This extended contact with the lees can enhance the wine’s texture, mouthfeel, and overall flavor development.

In addition to flavor and aroma development, yeast can also have a significant impact on the wine’s stability. Throughout fermentation, yeast consumes oxygen, which can minimize the risk of spoilage due to oxidation. Additionally, yeast can transform certain compounds in wine, making them less susceptible to spoilage and contributing to the wine’s longevity.

However, even though yeast is vital for fermentation and flavor development, its presence in the final product may vary. After fermentation, winemakers can choose to separate the wine from the yeast through a process called racking. Racking involves siphoning the wine off the lees, leaving behind the sediment.

In conclusion, when the wine has been placed on the yeast, fermentation occurs, transforming sugar into alcohol, carbon dioxide, and heat. The yeast cells produce various compounds that shape the wine’s aroma, flavor, and stability. Additionally, extended contact with yeast, known as lees aging, can enhance the wine’s texture and development. Understanding the role of yeast in winemaking is crucial for producing a high-quality and well-balanced wine.