Tesco only invites critics to taste their wines on days deemed favorable on the biodynamic lunar calendar.

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.