ASTRINGENCY AND BITTERNESS OF SELECTED PHENOLICS IN WINE

Trained judges rated intensities of astringency and bitterness of four phenolic substances in white wine by scalar and time—intensity methods. According to scalar rating, astringency and bitterness increased as a linear function of concentration for catechin, gallic acid, grape seed tannin and tannic acid. The polymeric tannic acid and grape seed tannin were rated more astringent than bitter; the reverse was found for their respective monomers, gallic acid and catechin. Similar results were obtained for maximum intensity ratings by time—intensity methods. As maximum intensity of astringency or bitterness increased directly with concentration, the total duration of aftertaste increased; however, little or no changes in time to maximum were observed. A slightly longer time to maximum perception for bitterness was observed than for astringency. Copyright © 1990 John Wiley & Sons, Ltd