Autolysis: A closer look
Earlier this year I wrote an article about the Lee’s method. This article is sort of an extension of that and really digs into the process of Autolysis. Autolysis holds an important role in the creation of some of the world's best wines. This process, occurring during the fermentation and aging stages, contributes to the complex flavors, aromas, and textures that connoisseurs cherish.
Autolysis refers to the self-degradation of yeast cells, a natural occurrence that takes place when yeast cells die at the end of fermentation. Initially discovered by the revered French monk Dom Pérignon in the 17th century, autolysis was regarded with skepticism until the mid-20th century when its significance in winemaking became widely recognized.
During the fermentation process, yeast cells convert sugars into alcohol and carbon dioxide. However, once fermentation is complete, many yeast cells perish, settling at the bottom of the fermentation vessel. It's during this resting period, known as sur lie aging, that autolysis begins to exert its influence.
As yeast cells break down, they release various compounds into the wine, including proteins, amino acids, polysaccharides, and lipids. These substances interact with the wine, contributing to its overall complexity and mouthfeel. One of the most significant byproducts of autolysis is the release of mannoproteins, which play a vital role in enhancing the wine's texture and stability. Mannoproteins bind with tannins, softening the wine's astringency and promoting a smoother mouthfeel.
Autolysis influences the aromatic profile of the wine. Sulfer compounds, esters, and higher alcohols are released during autolysis, contributing to the wine's bouquet. These compounds can impart a range of aromas, from fruity and floral to nutty and toasty, depending on factors such as grape variety, fermentation conditions, and aging vessels. Bread and toast notes being the most common.
Champagne and other sparkling wines, in particular, owe much of their distinctive character to autolysis. The traditional method of producing Champagne involves aging the wine on its lees (spent yeast cells) for an extended period, sometimes several years. This prolonged contact allows for extensive autolysis, resulting in the development of complex flavors and a creamy mouthfeel synonymous with fine Champagne.
In addition to its role in flavor and aroma development, autolysis can also contribute to the wine's aging potential. The compounds released during autolysis act as antioxidants, helping to protect the wine from oxidative degradation over time. Wines aged on their lees often exhibit greater complexity and depth as they mature, a testament to the transformative power of autolysis.
While autolysis is a natural process, winemakers can influence its outcomes through various techniques. Stirring the lees, known as batonnage, can accelerate autolysis by increasing contact between the yeast cells and the wine. Additionally, selecting specific yeast strains and controlling fermentation temperatures can affect the timing and intensity of autolysis, allowing winemakers to tailor the process to achieve desired characteristics in the finished wine.
Autolysis is a fundamental yet often overlooked aspect of winemaking that significantly impacts the quality and character of the final product. From enhancing texture and mouthfeel to enriching aromas and flavors, the influence of autolysis extends far beyond the fermentation vessel.
