The Magic of Lees Beer

Lees , also known as lees-aged beer or sur lie beer, is a unique style of beer that undergoes a fermentation process similar to that of . This process involves aging the beer in contact with the lees, or sediment, left behind after fermentation.

The term “lees” refers to the dead cells and other particles that settle at the bottom of the fermentation vessel during the process. These lees contain a variety of compounds, including proteins, polysaccharides, and other organic material, which can contribute to the flavor, aroma, and texture of the beer.

In traditional brewing methods, the lees are typically separated from the liquid as soon as possible to produce a clear and clean beer. However, in the case of lees beer, the brewer intentionally allows the beer to age on the lees for an extended period of time, ranging from a few weeks to several months.

By aging the beer on the lees, the yeast cells continue to interact with the beer, releasing enzymes and metabolizing compounds in the process. This interaction can lead to the development of unique flavors and aromas in the beer, often described as nutty, yeasty, or brioche-like.

The extended contact with the lees also contributes to the mouthfeel and body of the beer. The proteins and polysaccharides in the lees can add a creamy and full texture to the beer, enhancing its overall sensory experience.

Lees beer is often associated with Belgian and French brewing traditions, where it has been practiced for centuries. These beers are typically bottle-conditioned, meaning that a small amount of sugar and yeast is added to the beer before bottling, allowing for a secondary fermentation to occur in the bottle. This secondary fermentation can further develop the flavors and carbonation in the beer.

It's important to note that lees beer may not be to everyone's taste. The flavors and aromas imparted by the lees can be quite distinct and may not appeal to those who prefer cleaner and crisper beer styles. However, for those who appreciate the complexity and depth that lees aging can bring, these beers can be a true delight.

Lees beer is a unique style of beer that undergoes an aging process on the lees, or sediment, left behind after fermentation. This process can contribute to the development of complex flavors, aromas, and textures in the beer. While it may not be for everyone, those who appreciate the nuances of lees-aged beer can find it to be a truly rewarding experience.

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What Does Beer On Lees Mean?

Beer on lees refers to the practice of aging beer in contact with the yeast sediment, or lees, that forms during the fermentation process. This process is similar to the sur lie method used in winemaking. The beer is left in contact with the lees for a period of time, allowing it to develop complex flavors and aromas.

During fermentation, yeast converts sugars into and carbon dioxide. As the fermentation process nears completion, the yeast cells begin to settle at the bottom of the fermentation vessel. This sediment, known as lees, consists of dead yeast cells, residual sugars, and other particles.

By leaving the beer on lees, brewers can achieve several benefits:

1. Flavor development: The contact with the lees can contribute to the development of unique flavors and aromas in the beer. The dead yeast cells release compounds that interact with the beer, adding complexity and depth to the flavor profile.

2. Enhanced mouthfeel: The presence of yeast sediment can result in a fuller and creamier mouthfeel in the beer. This can add a desirable texture and body to the final product.

3. Clarification: While it may seem counterintuitive, leaving beer on lees can actually help clarify the brew. The yeast cells act as a natural fining agent, helping to settle out any remaining particles and haze, resulting in a clearer beer.

4. Shelf stability: Aging beer on lees can also contribute to its shelf stability. The yeast cells can scavenge oxygen and help protect the beer from oxidation, allowing it to maintain its freshness for a longer period of time.

It's important to note that the duration of aging on lees can vary depending on the desired flavor profile and style of beer. Some beers may only spend a few weeks on lees, while others may age for several months or even years.

Beer on lees refers to the process of aging beer in contact with the yeast sediment that forms during fermentation. This practice can contribute to flavor development, enhance mouthfeel, aid in clarification, and improve shelf stability.

What Does Lees Taste Like?

Lees, also known as sediment, are the remnants of yeast cells and other particles that settle at the bottom of wine or bottles during the aging process. When wine is left in contact with these lees for an extended period of time, it can develop unique flavors and characteristics.

The taste of lees can vary depending on factors such as the type of wine, the duration of contact, and the specific yeast strains involved. However, there are some common descriptors often used to describe the taste of wine that has undergone sur lie aging:

1. Creamy: Wines aged on lees tend to have a smoother, creamier texture on the palate. This is due to the interaction between the lees and the wine, which can impart a velvety mouthfeel.

2. Nutty: Lees aging can contribute nutty flavors to the wine, such as almond or hazelnut. These flavors can add complexity and depth to the overall taste profile.

3. Yeasty: The presence of yeast in contact with the wine can result in a distinct yeasty or bread-like aroma and taste. This can be reminiscent of freshly baked bread or even a warm brioche.

4. Toasty: In addition to the yeasty notes, lees aging can also impart toasty or biscuity flavors to the wine. This can be reminiscent of toasted bread or pastry.

5. Round and full-bodied: Wines that have undergone sur lie aging often exhibit a fuller body and a rounder mouthfeel. This can enhance the overall richness and complexity of the wine.

It's important to note that the impact of lees aging on the taste of wine can vary depending on the specific winemaking techniques employed and the individual characteristics of the wine. Some wines may benefit more from sur lie aging than others, and winemakers carefully monitor the process to achieve the desired flavor profile.

The taste of lees in wine can be described as creamy, nutty, yeasty, toasty, and contributing to a round and full-bodied mouthfeel. These flavors and characteristics are the result of the interaction between the lees and the wine during the aging process.


Lees beer is a unique and intriguing style of beer that results from the fermentation process and the presence of yeast sediment, known as lees. This sediment, which consists of dead yeast cells and other particles, adds depth and complexity to the beer, contributing to its distinctive flavors and aromas.

Lees beer is often aged on the lees, allowing the beer to develop rich, round, and creamy characteristics. This aging process can result in flavors that are reminiscent of warm brioche or nutty notes, creating a truly unique drinking experience.

The presence of lees in beer also plays a role in the clarity and appearance of the final product. While some brewers prefer to separate the gross lees quickly from the liquid, others may choose to leave them in the beer for a longer period, adding a slight haze or cloudiness to the beer's appearance. This can enhance the overall drinking experience by adding visual interest and indicating the beer's unique brewing process.

Lees beer offers beer enthusiasts a fascinating exploration of flavors, textures, and aromas. Its connection to the traditional French method of sur lie aging adds a touch of sophistication and elegance to the beer, making it a sought-after style among connoisseurs. So, if you're looking to expand your beer palate and try something truly distinctive, give lees beer a try and immerse yourself in its complex and captivating characteristics.

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Thomas Ashford

Thomas Ashford is a highly educated brewer with years of experience in the industry. He has a Bachelor Degree in Chemistry and a Master Degree in Brewing Science. He is also BJCP Certified Beer Judge. Tom has worked hard to become one of the most experienced brewers in the industry. He has experience monitoring brewhouse and cellaring operations, coordinating brewhouse projects, and optimizing brewery operations for maximum efficiency. He is also familiar mixology and an experienced sommelier. Tom is an expert organizer of beer festivals, wine tastings, and brewery tours.