Lager styles are a relatively recent on the global beer scene, when one considers the centuries of ale brewing that predated the production of lagers. The simple difference between a lager and an ale is that the yeast employed for fermentation of a lager works at a cooler temperature and sinks to the bottom of the fermentation vessel, while ale yeasts work at higher temperatures and rise to the top of the vessel. Hence lagers are "bottom fermented" beers.