The inhibitory effect of barley steep-out waters was assessed using a new, quick and simple test, based on 24-h barley germination percentage. This original 24-h test was especially relevant for quantifying the inhibitory effect of steep-out water samples, as compared with a conventional 7- to-8-day malting process. The results made it possible to rapidly compare the effect of water samples of different qualities, especially after 3 successive recycling experiments of steep-out waters into the steeping step of barley malting process. The test was used to emphasise the difference of the inhibitory effects of steep-out waters collected from various industrial malting plants. Such a test can be used for investigations on the identification and the elimination of inhibitors.