The term 'Stein Fillers' refers to a job in the brewing industry. Stein Fillers are responsible for filling steins, or beer mugs, with beer from a tap. They must ensure that the steins are filled to the correct level and that the beer is of the highest quality. The job of a Stein Filler is often combined with other roles in the brewery, such as cleaning and maintaining the taps and equipment. Ales, which is the answer to the crossword puzzle, is a type of beer that is brewed using top-fermenting yeast.