In these days of pile 'em high and sell 'em cheap for wine, it would be understandable if the idea of a biodynamic calendar would cut little cloth with the larger retailers. Not so, as Chris Losh reports.

Supermarkets: big, tough, unsentimental. Ruthless, even, in the pursuit of profit. So imagine my surprise at a Tesco range tasting a couple of weeks back when I discovered that the date had been at least partially selected according to the biodynamic calendar. It's a bit like discovering that a shark has a liking for the Romantic Poets.

In case you didn't already know, according to Maria Thun's biodynamic calendar, each day is associated with an element. So there are root days, leaf days, flower days and fruit days. In the vineyard, some are better for picking, others for pruning, and so on.

But there is also a school of thought that the cosmic calendar continues to affect wines long after the grapes have been picked, fermented and bottled. According to devotees of biodynamism, wines taste better on fruit days.

It's the kind of assertion that tends to polarise the trade - at least off the record. While ringing round for this column, it was noticeable that, although there were relatively few voices coming out unequivocally in favour of biodynamism and its effects, equally there was also a lack of hard-core sceptics.

"This idea [of scheduling our tasting according to the biodynamic calendar] is something we have flirted with in the past," says Dan Coward at powerful importers Bibendum. "We have never planned our tastings according to the calendar as there are so many other considerations that this comes pretty far down the list. That said, we do usually check what to expect as the day arrives. And certain of our buying team do believe it makes a small amount of difference."

Hardly a ringing endorsement, but those "small amounts of difference" could be significant. If a wine tastes even 5% better on a fruit day than a root day, that could mean more listings.

Certainly, we've all been at tastings where wines just didn't show.

There are, of course, personal issues at play here - people taste differently on different days, for instance. But I've done panel tastings where entire groups of top quality tasters have ended up shaking their heads at the disappointing quality of a supposedly stellar line-up of wines.

But whether this is due to the concepts outlined in Rudolf Steiner's biodynamic theories is open to question, as fully-qualified scientist, and creator of the website, Dr Jamie Goode, points out.

"[Wines tasting different] could be because of a number of factors," he says. "What about air pressure differences, or relative humidity, or ambient temperature in the room? Then there are a whole host of pyschological factors that could make wine taste different on different days - such as knowing that a wine is supposed to taste good on a particular day.

"I can't see how alignment of planets will affect perception because they are so far away, unless you are claiming some metaphysical effect. Still," he concludes magnanimously, "we scientists don't know everything, and we have to try not to be dogmatic about issues such as this."

In fact, for devotees of biodynamism, such as winemaker Alvaro Espinoza of Vinedos Organicos Emiliana in Chile, contrary to what the scientific community think, it's more unnatural to believe that the movement of planets and the moon will have no effect at all. If the moon can affect the performance of vast bodies of water, he points out, then surely it's not too far-fetched to see it influencing the sap in a vine.

"As humans we're separated from the cosmic rhythms," he says, "but for animals it's very important. We try to work with the plants at the times when they are most open to it."

There is, to be sure, something appealing about Steiner's ideas. Born out of the 1920s, as mechanisation and industrialisation were first taking hold in European farming, the way in which they renounce science in favour of a more natural approach - special homeopathic preparations rather than pesticides or fertiliser; mixed crops and habitat breaks rather than monoculture; 'closed' cycle of nutrients, with nothing brought into the farm from outside - is beguiling.

Whether there is any rigour to it, though, is another question.

Certainly, there seems to be no research anywhere that suggest that biodynamic wines taste any better than organic, say. Or even than ordinary non-green wines.

Consumer ignorance, too, remains profound, with biodynamics lumped, along with organics and Fairtrade, into a fuzzy part of the brain marked 'ethical feel-good factor'.

All of which suggests that, for all its laudable aims and intentions, from a production level at least, biodynamics is a route that is best followed for personal reasons, rather than quantifiable improvements in quality.

Though as an emotional adherent but logical sceptic on the issue, if any readers out there have any rigorous research or personal stories on the matter, I'd love to hear them.