Red or white - who cares?

Cautious wine drinkers have now and again discovered a red that drinks well, or at least tolerably, with fish - in Derek Taylor's case, usually because he's run out of white.

But far more discerning palates than mine have been unable to explain why or how these few and occasional exceptions have broken the age-old rule of pairing fish with white wines. And it is true: red wine is almost certain to turn seafood into a strongly offensive fishy taste that lingers unpleasantly.

For want of a scientific explanation, this phenomenon has usually been blamed on tannins, the chemicals that cause red wines to taste dry - or even mouth-puckeringly astringent.

Now the splendid Journal of Agricultural and Food Chemistry (it often features naked pictures of microbes) has reported the solution to this great mystery. The journal says that a brilliant Japanese researcher, Mr Takayuki Tamuri, and his team have tested red and white wines, reinforced wines and dessert wines in coded glasses and random order with consistent samples of scallops.

Seven experienced wine tasters were employed to rate each wine/scallop pairing by the presence of any fishy aftertaste on a scale of zero to four: zero indicating no aftertaste and four an extremely strong one.

They found that the offending red wines were those that contained a high level of iron.

A second experiment with the offending wines treated them with a chelating agent which isolated the dissolved iron and made it chemically inert. The fishy taste vanished.

Then they added iron to red wines that had scored well with fish. They immediately produced the offending foul fishy taste.

The tests also found that high-acid white wines tasted best of all with fish.

There is no way of predicting - from the terroir, the earth in which the vines grow - to what degree red wines will contain iron. But it is now possible from early tank testing to be able to add to the labels of many red wines without a significant iron content: This wine goes well with fish.

Now I'll just have another peek at those nude bacteria.

• This article was originally published on page 12 of The Sunday Tribune on November 15, 2009