A viscometric protocol to determine endo-Beta-1,3-glucanase in barley malts using the Rapid Visco Analyzer (RVA) from Newport Scientific (Australia) is described. Activity is determined in an 8-minute test using Curdlan, a microbial Beta-1,3 linked glucose polymer, as substrate at pH 5.0. Curdlan is an unmodified polymer that undergoes two gellations that are easily observed and measured using the RVA. Because Curdlan is a native substrate, the problems often encountered using derivatized substrates are obviated. The protocol does not require pre-extraction of the malt. Enzyme activity is proportional to the reduction in viscosity from the substrate blank. The importance of the activity is not known since the presence of endogenous substrate in the native grain is limited and not well understood. However, Beta-1,3-glucanases have been identified among the "pathogenesis-related" proteins that accumulate in plants challenged with viruses, fungi, or bacteria.