A double antibody, sandwich enzyme-linked immunosorbent assay (ELISA) was developed using polyclonal antibodies specific tobeta-amylase to estimate the amount of ‘free’ (soluble in aqueous saline solution) or ‘combined’ (extracted with saline solution including reducing agent)beta-amylase protein in barley grain and malt. This ELISA was used to quantify the amount ofbeta-amylase in barley grain and malt from four varieties grown at nine sites in South Australia in 1993. The antibody used to develop the ELISA reacted differently withbeta-amylase depending on whether the source was barley grain or malt, and on thebeta-amylase band pattern in isoelectric focussing (IEF) of the barley variety. On the basis of their IEF band patterns barley varieties were divided into two types, designatedBmy1-Sd1 andBmy1-Sd2. Malting resulted in proteolytic cleavage of thebeta-amylase peptide with a reduction in the apparent molecular weight of up toM r 4000 and the appearance of new maltbeta-amylase IEF bands that were more basic. The new maltbeta-amylase IEF band patterns still allowed the identification of theBmy1-Sd1 andBmy1-Sd2 IEF types despite the change in molecular weight and pI. The data obtained using thebeta-amylase ELISA were highly correlated withbeta-amylase activity for both the free and combined fractions when the IEF band pattern and its source, barley grain or malt, were taken into account.