Credulous wine-sellers in the UK are encouraging their customers to avoid drinking wine on certain days of the month on the grounds that the lunar cycle will alter the taste of the wine. Horoscopes for wine — now that's a whole new kind of dumb.

The idea that the taste of wine changes with the lunar calendar is gaining credibility among the UK's major retailers, who believe the day, and even hour, on which wine is drunk alters its taste. Tesco and its rival Marks & Spencer, which sell about a third of all wine drunk in Britain, now invite critics to taste their ranges only at times when the biodynamic calendar suggests they will show at their best.

Marks & Spencer has gone a step further and is advising customers to avoid disappointment from the best bottles by making sure not to open them on "root" days…

In other quarters, doubts remain. Waitrose's wine department has investigated the idea and cannot see a correlation. Many scientists have little time for biodynamic wine, pointing out that the movement's guru, Rudolf Steiner, claimed to have conceived the concept after consulting telepathically with spirits beyond the realm of the material world. Among his other works are claims that the human race is as old as the Earth and descended from creatures with jelly-like bodies, and a belief that men's passions seep into the Earth's interior, where they trigger earthquakes and volcanoes.