These cells are the remnants of the fermentation process, where yeast consumes sugars and converts them into alcohol. The lees can be found in the bottom of wine barrels, tanks, or bottles, and they play a crucial role in the development of the wine’s flavor, texture, and overall character.

The Science Behind Lees

Lees are formed when yeast cells die and settle at the bottom of a vessel. This process is a natural part of the fermentation process, and it occurs when the yeast cells have consumed all the available sugars in the wine. The lees are composed of dead yeast cells, proteins, and other organic compounds that are left behind after fermentation is complete. These compounds can contribute to the development of the wine’s flavor, texture, and aroma. * The lees can be classified into three main types: + Fine lees: These are the smallest and most delicate lees, which are often found in high-end wines. They are composed of tiny yeast cells and other organic compounds that are left behind after fermentation.

However, some wine producers choose to leave the wine on the lees for a period of time, a practice known as lees aging or lees contact. This practice has been used for centuries in the production of certain types of wine, such as Chablis and Champagne.

Understanding Lees Aging

What are Lees? Lees, also known as sediment, are the dead yeast cells and other particles that accumulate at the bottom of a wine barrel or tank during fermentation. These particles can impart unique flavors and textures to the wine, and can also contribute to the overall character of the wine.

Lees aging can add depth and complexity to wine, but requires careful management to avoid unwanted flavors.

However, the lees can also impart unwanted flavours such as a nutty, stale or cardboard-like taste if the wine is not regularly stirred or if the lees are not properly managed.

The Benefits of Lees Aging

Lees aging, also known as lees contact, is a winemaking technique that involves allowing the wine to age in contact with the dead yeast cells, also known as lees, that remain in the tank or barrel after fermentation. This process can add multiple benefits to the wine, including:

How Lees Aging Works

When a wine is left in contact with its lees, the dead yeast cells undergo a process called autolysis.

These protein molecules are broken down into smaller peptides and amino acids, which are then absorbed by the yeast during fermentation. The yeast then uses these amino acids to build new proteins, which are then broken down into smaller peptides and amino acids, and so on.

The Science Behind Sur Lie Ageing

Sur lie ageing is a process that involves the use of a liquid, typically wine, to cover the surface of the dough during fermentation. This liquid is usually a wine that is not yet fully fermented, and it serves several purposes. Firstly, it helps to prevent the growth of unwanted microorganisms that can spoil the dough. Secondly, it provides a source of nutrients for the yeast, which is essential for fermentation to occur.

The Role of Yeast in Fermentation

Yeast is a microorganism that plays a crucial role in fermentation. It is responsible for converting the sugars present in the dough into carbon dioxide gas and ethanol. The yeast uses the amino acids present in the dough to build new proteins, which are then broken down into smaller peptides and amino acids.

The Art of Ageing on the Lees

Ageing on the lees, also known as lees ageing, is a winemaking technique that involves leaving the wine in contact with the sediment at the bottom of the barrel or tank for an extended period. This process can significantly impact the flavor, texture, and overall character of the wine.

Understanding the Benefits

The Science Behind Lees Ageing

Lees ageing is based on the concept of sedimentation, where the wine interacts with the sediment, causing the particles to settle and the wine to clarify. This process can also lead to the formation of compounds that contribute to the wine’s flavor and aroma.

Factors Influencing Lees Ageing