What occurs during the bottle conditioning process?

During the bottle conditioning process, additional sugar and yeast are added to the beer just before it is sealed in bottles. This practice allows for a second fermentation to take place within the bottle, which generates carbon dioxide and creates natural carbonation. The yeast consumes the added sugar, producing both alcohol and carbon dioxide, which contributes to the beer’s effervescence and enhances its complexity and flavor profile.

This method differs from other carbonation techniques, such as force carbonation, where CO2 is injected into the beer under pressure. Bottle conditioning is particularly celebrated in many traditional brewing styles, as it can develop a unique character and a natural foam, which is often preferred by craft beer enthusiasts.

In contrast, aging beer in barrels, filtering before packaging, and pasteurizing before bottling are separate processes that serve different purposes and do not involve the natural carbonation that occurs during bottle conditioning.