Beer Steins are drinks that can give you an extra stamina boost by 15~20 points. This isn't a permanent upgrade, though. The stamina bar will add a small green bar to the stamina meter as soon as you take it. After Blazkowicz uses it, he only has his regular stamina to rely on. It is recommended that you save the extra boost for when you need it most. Beer Steins are more common than Brandy glasses, which has similar effect.