Weizenbier or Hefeweizen, in the southern parts of Bavaria usually called Weißbier (literally "white beer", but the name probably derives from "Weizenbier", "wheat beer"), is a beer, traditionally from Bavaria, in which a significant proportion of malted barley is replaced with malted wheat. By German law, Weißbiers brewed in Germany must be fermented using a "top-fermenting" yeast, which is technically an "ale yeast". Specialized strains of yeast are used which produce overtones of banana and clove as by-products of fermentation. Weißbier is so called because it was, at the time of its inception, paler in color than Munich's traditional brown beer. It is well known throughout Germany, though better known as Weizen ("Wheat") outside Bavaria. The terms "Hefeweizen" ("yeast wheat") or Hefeweißbier refer to wheat beer in its traditional, unfiltered form. The term "Kristallweizen" (crystal wheat), or "Kristallweißbier" (crystal white beer), refers to a wheat beer that is filtered to remove the yeast and wheat proteins which contribute to its cloudy appearance.