Malt conditioning using cold water spray.
In the malt conditioning system discussed, the thoroughly cleaned malt was conveyed to the 5 roll universal mill by a close tolerance screw conveyor (24 ft x 12 in diam.). In the initial part of the conveyor the grain was sprayed with cold water from 4 hollow cone nozzles with orifice diam. 0.024 in and spray angle of 70 degrees, set 8 in apart. The outlet water pressure was 100 lb and a moisture addition of 1.5% was found satisfactory. The moistened malt was held in the remaining part of the screw conveyor for 90 sec. The grinding speed of the mill was reduced from 190 lb malt/min with unconditioned malt to 120 to 130 lb/min. The mill settings adopted were: 1st pass, 0.055 in; 2nd pass, 0.045 in; and 3rd pass, 0.025 in. After grinding the density of the conditoned malt was 22 lb/ft3 compared to 25 to 28 lb/ft3 in the control. Extensive trials showed that conditioning of the malt afforded improvements in yield of 1.0% with lager and 1.2% with ales. In addition, running off times were shortened by about 20 min. Beers brewed from conditioned and unconditioned malts showed similar analysis except with regard to colour (conditioned malt, 3.5; control 3.9) but a taste panel significantly 5% identified the odd beer and preferred that brewed from the conditioned malt.
Keywords: barley beer flavour husk malting spraying water