Changes in sorghum malt during storage

Abstract

The diastatic power of the freshly kilned sorghum malt at 68.1°WK had a 29% drop after six months of storage. Freshly kilned sorghum malt displayed high wort turbidity (4.9 EBC) which dropped to 0.95 EBC and 1 EBC after 2 and 6 months of storage respectively. The colour of the malt worts faded slightly over the trial period from 7.6 EBC in freshly kilned malt to 6.8 EBC after six months. Extract remained fairly steady throughout the study period most likely due to the use of external amylolytic enzymes during mashing. The protein in extract/protein in grain fluctuated between 46.6% in the freshly kilned malt to 43.2% at the end of six months. The apparent extract after final attenuation (AEFA) indicates more fermentability beginning from two months after storage. Free α-amino nitrogen (FAN) dropped from 238 mg/L to 194 mg/L after six months of storage. Mash filtration with a micro-mash filter remained prolonged (86-93 min) throughout the six months of storage.