Takayuki Tamura and colleagues note that wine connoisseurs established the rule of thumb because of the flavor clash between red wine and fish. They point out, however, that there are exceptions to the rule, with some red wines actually going well with seafood. Until now, nobody could consistently predict which wines might trigger a fishy aftertaste because of the lack of knowledge about its cause.

The scientists asked wine tasters to sample 38 red wines and 26 white wines while dining on scallops. Some of the wines contained small amounts of iron, which varied by country of origin, variety, and vintage. They found that wines with high amounts of iron had a more intensely fishy aftertaste. This fishy taste diminished, on the other hand, when the researchers added a substance that binds up iron. The findings indicate that iron is the key factor in the fishy aftertaste of wine-seafood pairings, the researchers say, suggesting that low-iron red wines might be a good match with seafood.

Journal reference:

1.Tamura et al. Iron Is an Essential Cause of Fishy Aftertaste Formation in Wine and Seafood Pairing. Journal of Agricultural and Food Chemistry, 2009; 57 (18)