Quality specific differences in human taste detection thresholds as a function of stimulus volume.

Taste detection thresholds for sodium chloride, sucrose, citric acid and quinine sulfate were determined with the Henkin three drop forced-choice method at stimulus volumes 0.05 ml, 0.50 ml, and 0.90 ml, with and without water rinses. Taste thresholds were inversely related to stimulus volume (median rs = -.68 and, within each volume, thresholds did not differ as function of water rinsing. The detection thresholds for sodium chloride (range: 15.06 mM to 6.7 mM), sucrose (range: 24.22 mM to 14.13 mM), citric acid (range: 1.47 mM to 0.5 mM) and quinine sulfate (range: 0.35 mM to 0.12 mM) were similar to those of other investigators using considerably larger stimulus volumes and different psychophysical procedures. The present results demonstrate that the Henkin three drop method provides a more optimal measure of changes in taste sensitivity when stimulus volumes of approximately 1 ml are used in place of the standard 0.05 ml stimulus volume.