EFFECT OF WINE TYPE ON THE DETECTION THRESHOLD FOR DIACETYL

Diacetyl, an important wine flavorant synthesized during alcoholic and malolactic fermentation, has been reported to have a sensory threshol d of 2-3 mg/l. A comparative study of threshold for diacetyl in wines was undertaken to determine the effect of wine type on that value. Sen sory threshold was determined according to the forced-choice ascending concentration series of limits method described by ASTM (E 679-79), u sing trained panelists. Panel detection thresholds and standard deviat ion from the geometric mean were found to be 0.2 mg/l and 0.32 in Char donnay, 0.9 mg/l and 0.21 in Pinot noir, and 2.8 mg/l and 0.38 in Cabe rnet Sauvignon. These results demonstrate the important effect of wine type on diacetyl threshold, invalidating the use of a single threshol d value for all wines.