Methods for accelerating malting, a small scale investigation

It was confirmed that steeping fully after‐ripened barley at 25° or 30°c, for various periods, induces different degrees of ‘water sensitivity’. Germination of such warm‐steeped grain, set to grow at the steeping temperature, was maximal when the moisture content was about 35%. Sprays of hydrogen peroxide, applied immediately after draining the steeped grain, accelerated the subsequent germination of warm‐steeped barley when grown at elevated temperatures. Exceptionally rapid steeping/germination schedules were elaborated, using micromalting techniques. For example, fully mature grain was steeped, (7 h 25°c) to a moisture content of about 36%. All subsequent processing was also at 25°c. After a drain (2 h) the grain was sprayed with a solution of gibberellic acid (0·25 mg/kg) in a dilute solution of hydrogen peroxide (2·5 vol.). Spraying with water was carried out twice more during the germination period to increase the moisture content of the barley to about 44%. The grain was set to kiln at 43°c, 48 h from steep out, that is 55 h from first wetting. Kilning conditions were chosen to allow maximal survival of enzymes. The malt had a hot water extract above 103 lb/Qr (fine grind, on dry matter) and was made at the expense of a 7·5% malting loss. It was acceptable by other analytical criteria. If the second water spray was replaced by a spray of a dilute solution of sulphur dioxide (400 mgjkg) a malt having an extract of 103·5 lb/Qr was obtained with a malting loss of 5·8%, but yielding more soluble nitrogen. The possibility of achieving even shorter processing times, by working at 30°c, was noted.