The Role of Lees in Wine: Technique or Chance?
Wine lees are one of the most fascinating and underrated tools in winemaking. To many consumers, lees may look like nothing more than a residue of fermentation, something to be removed. Yet for experienced winemakers they represent a world of possibility, a way to raise a wine’s quality and create unique sensory experiences. But what are lees, exactly? And how did they go from “waste” to a central element in the production of premium wines?
Lees consist mainly of dead yeast cells, small fragments of grape skin and other solids left behind after fermentation. For centuries they were seen as a natural consequence of winemaking, but not necessarily as something beneficial. It was only over time, and with the evolution of oenological knowledge, that the true potential of lees was discovered.
The history of lees in wine is also the history of the evolution of winemaking. From ancient times, when wine was stored in amphorae and contact with the lees was inevitable, to the present day, where their use is deliberate and meticulously controlled, lees have played an essential role in the creation of quality wines. This transformation from waste to resource is a testament to the creativity and accumulated experience of generations of producers.
Today, lees are a key ingredient for giving wine more texture, aromatic complexity and stability. In white wines and sparkling wines in particular, contact with the lees can bring a creamy richness, notes of dried fruit and a complexity that would not be possible any other way. Even in red wines, lees can play an important role, helping to soften tannins and add body.
The appeal of lees is not confined to their tactile and aromatic results. They are also a link between wine and nature. They represent the full cycle of the grape, from vine to bottle, symbolising a deep connection between terroir, producer and consumer. This symbolic dimension contributes to the growing appreciation of wines made by traditional methods, where contact with the lees is regarded as an authentic, cultural element.
The use of lees is also an expression of sustainability. By making use of this “waste”, producers reduce loss and create more natural wines, in tune with the trend towards conscious consumption. It reinforces the idea that every component of the winemaking process has a purpose and can be turned to good account to create something extraordinary.
So what at first glance may look like a technical detail or a production quirk turns out to be one of the most captivating aspects of the world of wine. Wine lees are a technique, but also a genuine invitation to explore the magic of winemaking in all its dimensions.
The Origins and History of Lees in Wine
The practice of leaving wine in contact with its lees dates back to the earliest days of winemaking. In antiquity, cultures such as the Egyptian, Greek and Roman civilisations were already producing wine using rudimentary vessels, such as clay amphorae. In these vessels the lees accumulated naturally, and producers noticed that wines stored this way took on distinctive characteristics. Although there was no scientific knowledge at the time to explain these effects, it was already sensed that something special happened during this prolonged contact.
The Greeks, pioneers in the study of wine, recorded rudimentary practices related to the lees. They regarded lees as an “essence” of the wine, connected directly to the soil and to nature. Aristotle, for instance, noted that the most complex and rich wines often resulted from less interventionist techniques, in which the lees played a significant part.
The Romans, great innovators of winemaking, refined these practices and began to use lees more deliberately. The wines they produced were often transported in amphorae over long distances, during which they remained in contact with the lees. This process preserved the wines and also contributed to the development of more complex aromas and flavours, such as notes of walnut, honey and spice.
In the Middle Ages, Europe’s monasteries carried these practices forward. The monks, responsible for some of the most important oenological discoveries, documented that prolonged contact with the lees contributed to the longevity of wines. In regions such as Burgundy, this technique was taken to new heights, shaping the production of rich, elegant white wines that remain a world reference today.
With the advance of oenological science in the twentieth century, it finally became possible to understand the role of lees in wine. Detailed studies revealed that compounds released by the lees, such as polysaccharides and amino acids, have a direct impact on texture, stability and aromatic complexity. This knowledge allowed producers to apply more precise, controlled techniques, raising wine quality to unprecedented levels.
Thus the use of lees evolved from an intuitive practice into a scientific and artistic approach. Today lees are valued for their technical role and also for the cultural heritage they carry, representing centuries of experimentation and refinement in the art of making wine.
The Autolysis Process: The Science Behind the Lees
Contact between wine and its lees sets off a fascinating phenomenon that is crucial to the final quality of the product: the process of autolysis. During this process, which occurs after fermentation, the dead yeast cells gradually begin to break down, releasing compounds that interact with the components of the wine in a unique way.
Autolysis is, essentially, a slow-motion chemical transformation. As the yeasts disintegrate, they release mannoproteins, polysaccharides and amino acids, substances that play fundamental roles in the texture, stability and sensory profile of the wine. This phenomenon, which can last months or even years, is particularly evident in wines that benefit from prolonged lees contact, such as white wines built for ageing and high-quality sparkling wines.
Chemical and Sensory Benefits
One of the main benefits of autolysis is the improvement of the wine’s texture. The polysaccharides released increase viscosity and give a richer, more velvety sense of body. This effect is especially desirable in full-bodied white wines, where creaminess can lift the tasting experience to a higher level.
Mannoproteins also play a crucial part in stabilising the wine. These molecules help to prevent the formation of tartrate crystals and contribute to the retention of volatile aromatic compounds, ensuring that the wine preserves its delicate aromas as it ages. This is why many wines that undergo autolysis show complex aromatic notes, such as toasted bread, dried fruit and honey.
Time and Patience: Essential Elements
Autolysis is a process that demands time and patience, two virtues that define the production of premium wines. In sparkling wines made by the traditional method, for example, lees contact can last several years. During this period the wine acquires characteristics that would be impossible to achieve by other means, such as a creamy mousse and aromas of brioche and almonds.
In white wines built for ageing, on the other hand, autolysis helps to develop a depth and complexity that set these wines apart from younger, simpler bottlings. This balance between science and art is what makes the use of lees such a fascinating and essential practice in modern winemaking.
Wine Styles and the Different Effects of Lees
Lees play different roles depending on the style and type of wine, each contributing in its own way to the final profile.
In white wines, for example, prolonged lees contact is often used to create creamier textures and add an aromatic complexity that elevates the wine. Grape varieties such as Chardonnay and Viosinho benefit enormously from this contact, resulting in rich, elegant wines built for long ageing.
In sparkling wines, especially those made by the traditional method, lees have an essential function. During “sur lie” ageing, sparkling wines take on a refined effervescence, accompanied by aromatic notes of brioche, dried fruit and honey. This technique is widely used in regions such as Champagne, where prolonged lees contact is one of the pillars of quality.
In red wines, lees contact is less common, but it can be a valuable tool in specific cases. When well applied, it can help to soften overly aggressive tannins, add body and harmonise the whole. This practice is particularly useful in wines made from naturally tannic varieties, such as Tinta Roriz or Cabernet Sauvignon.
In fortified wines, such as Port or Madeira, lees play a more discreet role because of the fortification process and the high alcohol content, which already give the wine stability. Even so, the initial contact with the lees during fermentation can positively influence the development of complex, structured flavours.
Cellar Practices: Managing the Lees
Managing lees contact in the cellar is a practice that demands experience and attention to detail. Among the most common techniques is bâtonnage, a process that involves regularly stirring the wine to reincorporate the fine lees. This practice, frequently used in white and sparkling wines, allows the beneficial compounds of the lees to be integrated into the wine more effectively, contributing to a creamy texture and to stability.
Another common practice is the careful selection of the lees. Not all lees are alike: while fine lees are rich in compounds such as polysaccharides and amino acids, gross lees can contain less desirable material, such as heavy sediment, which may introduce off-flavours or aromatic faults. Many cellars therefore opt for racking, separating the gross lees and discarding those that could compromise the quality of the wine.
Contact time is also a critical factor. Too long a period in contact with the lees can lead to the development of reductive aromas, such as notes of sulphur or rubber, while too short a time can limit the potential benefits. For this reason, winemakers monitor the wine’s evolution carefully, adjusting contact time as needed to reach the desired balance.
In addition, the storage temperature during lees contact can significantly influence the final result. Lower temperatures tend to preserve volatile aromatic compounds, while slightly higher temperatures can accelerate autolysis, intensifying the effect of the lees on the wine. Choosing the ideal temperature depends on the style of wine one wishes to produce, making this decision an essential part of cellar management.
Examples of Excellence: Wines Built on Extended Lees Ageing
The use of lees has been a milestone in the creation of iconic wines throughout history, with examples that reflect the mastery of producers and the singularity of each terroir. In the Champagne region, the traditional method of sparkling wine production is perhaps the best-known example of the positive impact of lees. The sparkling wines of this region spend years in contact with their lees, resulting in wines that combine a delicate mousse, a creamy texture and aromatic notes of brioche, almonds and dried fruit.
Another example is found in Burgundy, where the white wines of Montrachet are widely recognised for their richness and depth. Prolonged lees contact is a fundamental part of the winemaking process in this region, allowing the wines to develop an elegant structure and an enviable longevity.
In Portugal, the use of lees has also produced wines of excellence. In Vinho Verde, for example, many producers use contact with fine lees to add complexity and body to their whites. Varieties such as Viosinho in the Douro, Arinto in Lisboa and Alvarinho in Vinho Verde benefit particularly from this technique, resulting in balanced wines that combine freshness and depth.
Still in the Portuguese context, some red wines from the Douro region demonstrate the positive impact of lees. In these cases, bâtonnage is used to soften the tannins, balance the structure and add layers of flavour. Combined with modern winemaking practices, it has made it possible to create reds that stand out for their elegance and longevity.
In the Alsace region, white wines made with prolonged lees contact are prized for their velvety textures and aromas that evolve over time. Likewise, Italian sparkling wines such as Franciacorta show how the use of lees can raise complexity and deliver a long, memorable finish.
These examples underline how contact with the lees is a technical practice, and also a genuine expression of terroir and winemaking skill, standing out as a distinguishing feature in high-quality wines.
Challenges and Risks in the Use of Lees
Although lees are a valuable tool in winemaking, their use presents significant challenges and potential risks that call for a careful approach from producers. One of the main challenges is the proper management of the lees during the ageing of the wine. If lees contact is prolonged excessively or poorly controlled, it can lead to the development of undesirable aromas, such as reductive notes, which include smells of sulphur, rubber or rotten eggs. When too intense, these aromas compromise the quality of the wine and its acceptance by the consumer.
Another risk associated with the use of lees is the possibility of microbiological contamination. Although lees contain nutrients that can benefit the wine, they can also serve as a substrate for the growth of undesirable microorganisms, such as lactic or acetic bacteria. If good hygiene and monitoring practices are not in place in the cellar, these microorganisms can proliferate, leading to faults in the wine, such as high volatile acidity and unpleasant vinegar aromas.
Storage temperature is also a critical factor in the use of lees. Unsuitable temperatures can accelerate unwanted processes of degradation or make it harder to integrate the positive characteristics associated with the autolysis of the lees. It is essential that producers maintain rigorous control of temperature throughout the ageing process to ensure that the wine evolves harmoniously.
In addition, the management of lees requires special attention to the initial composition of the wine. Certain wine styles or grape varieties may not respond well to prolonged lees contact, resulting in unbalanced wines or in sensory characteristics that do not match consumers’ expectations. For this reason, the winemaker must carefully assess a wine’s potential before deciding to use lees as a tool for improvement.
Conclusion: An Indispensable and Fascinating Element
The use of lees in wine is far more than an oenological technique; it is an art that combines science, tradition and innovation. Lees are transformed from a simple residue into a powerful tool capable of raising the quality and complexity of a wine, from its texture and aromas to its longevity. Yet this practice demands knowledge, patience and a deep respect for natural processes.
Throughout history, lees have played a central role in the evolution of wine, shaping the way we perceive and value this ancient drink. Whether in renowned sparkling wines, prestigious whites or elegant reds, contact with the lees represents a commitment to authenticity and to the expression of terroir.
At the same time, the challenges associated with the use of lees, such as the risk of contamination or undesirable aromas, underline the importance of technical rigour and experience in managing this technique. Every decision, from contact time to storage temperature, can make the difference between an ordinary wine and an extraordinary one.
For wine lovers, understanding the role of lees is an opportunity to deepen their connection with wine. It is a way to appreciate the work, the dedication and the know-how that make each bottle unique.
So the next time you raise a glass of wine and feel its creamy textures or its complex aromas, remember the lees. They are a symbol of how nature and human artistry can come together to create something truly magical.
From the page to the glass
- Monte Cascas Reserva Branco Douro — Viosinho barrel-fermented with fortnightly bâtonnage.
- 1808 Espumante Brut Nature — Traditional method, twenty months on lees, no sugar at disgorgement.
