Lager is brewed from malted barley using a bottom-fermenting yeast. Although a relatively recent entry to the brewing world, lager yeast quickly had an enormous impact and lagers now number among the world's most popular beers. Lagers originated in Bavaria, where brewers fermented beer in cool caves and tunnels underground. The yeast they developed subsequently prefers lower temperatures, typically between 45 and 56 degrees Fahrenheit. The fermentation of Lager is slower than that of Ale. After fermentation, when Ale would be ready to drink, Lager continues to be stored. This extended storage is called aging. Aging may last months and the beer will be stored at temperatures as low as 32 degrees. Lager yeasts have a clean influence on the taste of the beer and will often step aside to allow other flavors to come through. Lagers exhibit the crisp and refreshing taste of malt and hops.