what is a lager

A lager is a type of beer that has been brewed and conditioned at low temperatures. The term "lager" comes from the German word for "storage," as the beer was traditionally stored before drinking, often in cool caves where it was also fermented. Lagers are distinguished from ales by the type of yeast used in the fermentation process. Lagers use a "bottom-fermenting" yeast called Saccharomyces pastorianus, which ferments at relatively cold temperatures and sinks to the bottom of the fermentation tank. In contrast, ales use "top-fermenting" yeasts that rise to the top of the tank during fermentation. The lower fermentation temperatures used in lager brewing reduce the number of by-products during the fermentation stage and produce a cleaner, crisper beer. Pale lager is the most widely consumed and commercially available style of beer.