Brewing was a winter activity, and ice was used to keep beer cool during the summer months. The beer called porter, made from a mixture of malt extracts was a strong dark beer drank by the marker porters in 18 century London . The style started off in Czechoslovakia in the aptly named town of Pilsen . A bock beer is a stronger , heavier Munich-type lager that is brewed in winter for drinking in the spring. Brewers often have their primary fermenting vessels on the top floor of the brewery so that they can open holes in their roofs to let the yeasts, rain, dirt and insects come down and flavour their beer.
Pale ale is lighter, paler and less bitter than porter.
Stouts are stronger kinds of mild ale. In Africa , beer is brewed from millet, sorghum, and other existing starch crops. In Russia , kvass is made from fermented rye bread. The Mexicans brew pulque from the fermented sap of the agave plant. The Samshu , in China , Suk in Korea , and Sake in Japan are all brewed from rice.