Bottle conditioning

In bottle conditioning, also called secondary fermentation, a small amount of sugar or wort is added to the beer before filling. The yeast still present ferments it in the sealed container, creating carbon dioxide naturally.

The beer keeps maturing in the bottle and may develop complex aromas. A fine yeast sediment remains at the bottom, which is left behind when pouring or, depending on the style (such as Hefeweizen), deliberately poured into the glass. The method is common for wheat beers, Belgian specialities and craft beers. Bottle-conditioned beers should be stored dark and cool and not shaken strongly.