Bottom of the Stein
Identifying old German beer steins requires a keen eye. The first thing that you have to look for is a Made in Germany label on the bottom of the stein. Most imitations have Made in China or Made in Taiwan labels on them. An authentic German beer stein will always have a Made in Germany label, so beware of any steins that don't have any mark at all. The mark may say Gemacht in Deutschland, which means Made in Germany. Some steins may also have the artist's name or the company's name that manufactured the stein.
Lid of the Stein
Old German beer steins usually feature metal lids. The lid is usually ornately decorated with something that complements the painting on the stein. In most cases, the inside of the lid is lighter than the outside of the lid. This is because the inside of the stein generally oxidizes slower than the outside since it is better protected from the elements. The exception to this rule is that if the stein is displayed open, the inside and outside may look the same. In that case, both the inside and the outside will appear dark.
Interior of the Stein
Look at the inside of the stein while holding it up to sunlight. German beer steins will have a lithophane on the bottom. However, the presence of a lithopane doesn't mean it is an old stein. If the picture contains any nudity or provocative scenes, it is a new stein. No old German beer steins contain nudity or provocative scenes. Also, old German beer steins may have awkward angles on most of the lithopane. This is because the lithopane is hand-painted.
Exterior of the Stein
Examining the exterior of the stein can tell you a lot about the stein. All old German beer steins have hand-painted pictures. Most of these depict historical scenes. Some may have raised edges. If the stein is a Regimental stein, it will contain names of soldiers. However, if any of the names contain a first name, the stein is new. Old regimental German beer steins contain only a rank and a last night.
Handle of the Stein
New German beer steins have a bump in the handle. Old German beer steins don't. However, the absence of this bump isn't a guarantee of an old beer stein. Somewhere between 10 to 20 percent of new steins don't have the bump.