LABORATORY MALTING. II. PRECISION

Abstract

The precision of the malting test made in equipment already described (Can. J. Research, C, 15: 204–216. 1937) was studied by making four batches of malt each of which contained duplicate malts made by eight treatments representing the combination of steeping for 48 or 60 hr., maintaining the germination chamber at 53° or 54.5° F., and kilning for 36 hr. at 100° to 175° F. or for 52 hr. at 90° to 165° F. The standard errors of duplicate tests made in the same and in different batches were found to be: extract, 0.08 and 0.09%; moisture, 0.04 and 0.05%; color, 0.04 and 0.05 units; diastatic power 1.0 and 2.8° L.; permanently soluble nitrogen as percentage of wort solids, 0.01 and 0.02%; malting loss 0.06 and 0.29%; and sprouts, 0.06 and 0.18%.On the average, increasing the time of steeping decreased extract by 0.08%; but increased diastatic power by 3.2° L., permanently soluble nitrogen by 0.05%, malting loss by 0.98% and sprouts by 0.44%. Increasing the temperature of the germination chamber increased diastatic power by 4.2° L., permanently soluble nitrogen by 0.04%, malting loss by 0.93%, and sprouts by 0.52%. Increasing the time and decreasing the temperature of kilning increased extract by 0.08% and diastatic power by 14.8° L. Statistical analyses show that the test is sufficiently precise to prove that these effects, though small, are significant.