Why Beer Steins Have Lids

Not all beer steins have lids but centuries ago it was required by law in Germany for a beer stein to have a lid. The purpose was to prevent the plague. It was thought that fleas getting into the beer spread disease which was true. Hence, the lid of a stein was born. 

German beer steins are highly collectible. They have been popular for hundreds of years because of their craftsmanship and motifs. Read more about beer steins at What is the Purpose of a German Beer Stein.