lager

Lager is a beer that is fermented at relatively cold temperatures. Lager is NOT an ale. Lager yeast strains perform best at these cold temperatures, while ale strains create a violent fermentation whose yeast is suspended in the whole column of the fermentation. Ale yeast can be 'cropped' from the top in a froth that collects from this violent CO2 production, and is therefore labelled "top fermentation" while lager yeast lies on the bottom of the fermenter. Hence "bottom fermentation". Pilsner is a style from Pilzn, which is a Czech style lager. It is what today's standard lagers are meant to be, but often miss the points of the style. The term 'lager' is German for aging, which refers to the 'secondary fermentation' where little CO2 is produced, yet yeast is still inside the vessel. Ales undergo little or no secondary fermentation, and get sent through a centrifuge or diatomaceous earth filter on the way to the bright tank for packaging. Some ales get racked directly to a cask for cask ales.