Factors which cause gushing in shaken beer are derived from malt and are active in unhopped beer; some malts are more prone to give gushing beer than are others. The gushing factors from malt are removed by boiling wort with hops, provided that the hops are of “good” quality and that the hop rate is sufficient; what makes for “good” quality in this respect is as yet undetermined. There can, however, be a further generation of gushing factors during fermentation.