Improvements in the characterisation and quality of vigour in malting barley

Malting conditions during steeping and germination must be optimised if sui tably modified malt is to be produced quickly and efficicently. The 'germin ation profile' which comprises a measurement of germinative energy (percent age germination, GH) over 3 d and calculations of germination index (mean g ermination time, GI) and germination homogeneity (uniformity of germination ,GH),were shown to provide an informative means of characterising the overa ll vigour and potential germination performance of barley grain under vario us conditions. These conditions included incubation temperatures of 10 degr ees C, 20 degrees C and 30 degrees C in petri-dishes and a range of volumes of water, from 0.5 ml to 2.5 ml, added to the incubation vessel (Erlenmeye r flasks). At 20 degrees C, GI was 5.71, higher than at 10 degrees C or 30 degrees C for intact grains, and 9.17 for partially de-husked grains. With 1.0 ml of water, GE was 98.5%, GI 5.00 and GH 53%. More water (2.5 mi) redu ced GE to 43.5%, but GI for the grain increased to 6.62. Priming experiment s were performed where barley grains were pre-treated by hydrating in water for up to 30 h, then dried back, prior to germination testing. Priming for 20 h was the optimum time required to improve vigour compared to the contr ol. This treatment resulted in a GI of 9.3 (maximum 10) compared to a value of 5.8 for the control and a GH of 74%, compared to 43.8% for the untreate d control grains. The priming treatments did not significantly alter the ge rminative energy values of the samples but these were already high for the control. It is concluded that malting barley quality control should include measurement of a 'germination profile' as a simple means of presenting and analysing the complex data obtained from measurements of germination made over 3 days.