You can pass a known quantity of panicles of grain moisture content of 20% through a laboratory thresher with known optimum threshing settings and then determine the percentage of unthreshed grains left on the panicle after passing through the thresher relative to the total grains on the panicle. The unthreshed grains are collected after inspecting the panicle and hand threshing the unthreshed grains. The threshability will be 100 minus the pecentage of unthreshed grains. Avoid using panicles with a high rate of poorly filled or diseased grains because this might affect the results.