Flaschengärung

Flaschengärung, also known as bottle fermentation, is a method used in beverage production, most notably for sparkling wines and certain beers. It involves the secondary fermentation of the beverage directly within the bottle in which it will be sold. This process creates carbonation as yeast consumes residual sugars, producing carbon dioxide that dissolves into the liquid.

In the context of sparkling wine, such as Champagne or Cava, flaschengärung is a traditional and highly regarded technique. After the initial fermentation, the wine is bottled with a small addition of sugar and yeast (liqueur de tirage). The bottles are then sealed with a crown cap, allowing the secondary fermentation to occur over a period of months or even years. The carbon dioxide produced is trapped, resulting in the characteristic bubbles. Following this, a process called riddling (remuage) is often employed to consolidate the yeast sediment at the neck of the bottle. Finally, disgorgement (dégorgement) removes this sediment before the bottle is resealed with a cork and wire cage.

For certain beers, particularly Belgian styles like Lambic and some farmhouse ales, flaschengärung is also used to achieve natural carbonation and can contribute complex flavors. The yeast used for this secondary fermentation can be the same as the primary fermenting yeast or a different strain, depending on the desired outcome. This method can lead to a more effervescent and sometimes less predictable carbonation compared to force carbonation.