As an expert sommelier and brewer, I can provide you with a detailed answer to the question of what is kept in kegs. Kegs are primarily used to store and dispense beer that has completed the fermentation process and is ready to be consumed. These kegs are commonly used for pressurized drinks, such as fizzy lagers, which require a controlled environment to maintain their carbonation levels.
The main contents of a keg are typically filtered and pasteurized beer. Filtering is a process that removes any remaining solids or sediments from the beer, resulting in a clear and visually appealing product. This step is crucial in ensuring that the beer poured from the keg is free from any unwanted particles that may affect its taste or appearance.
Pasteurization, on the other hand, involves subjecting the beer to heat in order to destroy any remaining yeast or bacteria. This helps to extend the shelf life of the beer and prevent any further fermentation or spoilage. By pasteurizing the beer before it is kegged, breweries can ensure that the product remains stable and fresh for a longer period of time.
It is worth noting that not all beers are suitable for kegging. While kegs are commonly used for fizzy lagers, other styles of beer, such as ales or stouts, may be better suited for different types of containers, such as bottles or cans. This is because certain beer styles may benefit from additional aging or conditioning, which can be achieved more effectively in a closed environment like a bottle.
In my personal experience as a brewer, kegs have been an essential part of the beer packaging process. They provide a convenient and efficient way to store and transport large quantities of beer, especially for commercial breweries. Kegs also offer the advantage of being reusable, reducing waste and environmental impact.
To summarize, kegs are primarily used to store filtered and pasteurized beer that has completed the fermentation process. They are commonly used for pressurized drinks, such as fizzy lagers, and provide a controlled environment to maintain carbonation levels. Kegs are a popular choice for breweries due to their convenience, efficiency, and reusability.