Odor sensitivity to geosmin enantiomers

Enantiomers of the earthy smelling odorant ‘geosmin’(t-1, 10-dimethyl-t-9-decalol) were tested on 52 human subjectsfor odor threshold ratio (+)/(–) variability. Thresholdconcentrations of (+) and (–) and their (+)/(–)ratios appeared to be monomodally distributed. For most subjects,the ratio varied within a predictable narrow range comparableto that found previously for carvone enantiomers and contraryto the large variability found for -ionone enantiomers (Polaket al., 1989). The natural occurring isomer, (–) geosminhad, on average an x11 lower threshold than (+).