Supermarkets are arranging wine tasting sessions around "good" and "bad" days as dictated by the lunar calendar. So does the Moon really change the taste of wine?
A German great-grandmother called Maria Thun is wielding huge influence on the British wine industry.
A calendar she first published in the 1950s categorises days as "fruit", "flower", "leaf" or "root", according to the Moon and stars. Wine is best on fruit days, followed by flower, leaf and root days. The worst day is marked as "unfavourable" in the calendar. (See factbox below for forthcoming "good" and "bad" days).
Tesco and Marks & Spencer are the latest supporters of her philosophy. The two supermarkets have revealed that they have a policy of inviting critics to taste their wine only on days which the calendar says are favourable.
Her theory is that wine is a living organism that responds to the Moon's rhythms in the same way that some people believe humans do. The so-called "lunar effect" has been widely dismissed as pseudo-science but its followers think that as the Moon exerts such a huge impact on the tides, it must follow that it affects the water in the human body and therefore human behaviour.
The belief that wine can taste different depending on the day it's drunk is not as eccentric as it may sound. All wine experts tend to agree - although their theories on why vary.
Wine merchant David Motion has recently been won over to Maria Thun's "biodynamic" calendar theory.
"We tried eight wines on Tuesday, which was a leaf day and then the same wines again on Thursday, which was a fruit day. And it was totally conclusive.
"It wasn't that the wine tasted bad on the Tuesday but it was much more expressive on the Thursday. It was more exuberant and on-song. It was like the heavens opened, the clouds parted and the wine just expressed itself."
The trial solved his long-standing puzzlement at why the same wine could taste so much better on certain days. From now on, he says, his wine shop in north London will only hold tasting sessions on fruit days.
The biodynamic calendar is part of the wider concept of biodynamic farming, pioneered by Rudolf Steiner in the 1920s. The philosophy is similar to organic farming but a key difference is that planting and sowing is timed according to the moon.
Biodynamic farming has itself had an influence on the growing industry - with some wine growers running their vineyards along these lines.
Despite its growing traction in viticulture there's still much scepticism in the trade, with some scientists dismissing it as sorcery.
The resident wine expert at London's Vinopolis, Tom Forrest, agrees it all sounds a "little bit like witchcraft".
"But having thought about it and spoken to biodynamic wine producers, I'm more sure there is some sort of influence. Whether it's a huge influence or not, I don't know."
The Moon can impact on a plant through changing water levels, he says, so there is something to be said for the way it can influence wine.
But Jamie Goode, a wine scientist and author of online magazine wineanorak, thinks too much is made of planetary alignments and the lunar calendar.
"But I'm not going to say it's absolute nonsense. Wine tastes different on different days but the differences are not that huge and the differences are more about atmospheric pressure.
"And we are part of the equation when it comes to tasting wine. We are not measuring devices. The taste of the wine is something we generate in response to the wine."
People taste wine with expectations, and part of that could be the knowledge that it is a "good" day for wine, he says. Mood also influences
There are other aspects of biodynamic farming that could explain why producers that switch to it from conventional methods tend to improve the quality of their wine, he says. And they have nothing to do with the Moon.
They don't use pesticides, they compost, they till manually and they use other crops to create a more diverse eco-system.
Below is a selection of your comments.
Leaving aside the question of whether or not this is fact or fancy, I wonder why the wine critics allow themsleves to be manipulated in this way? Surely they should insist on a level playing field for all tastings. In fact, surely the wine needs to be tasted on good and bad days to get a clear picture. Who's to say that a wine that is excellent on a fruit day is not a shocker on an root day, while another wine which is not as good on the fruit day might be a more steady performer, still being satisfactory on an unfavourable day?
Ray, Turku, Finland
It makes perfect sense to me. I've been growing vegetables according to the lunar calendar for the past year (but without following other biodynamic practices), with fantastic results. Big yields, delicious flavour, a greater ability to resist pests and diseases than I would normally expect. There will always be sceptics who are happy to rubbish any ideas that challenge their view of the world, but have they actually tried them out themselves?
The Moon creates tides because large masses of water are fluid, and free to be re-shaped. The effect is caused by the Moon's gravity, which has an equal effect upon *everything* all the time. The Moon's distance from a point on the Earth varies by a small percentage when is on the same or opposite side of the Earth from that point. People move around, facing towards or away from the Moon. We don't stand still, so the effect of its gravity upon our bodily fluids is entirely random. The fact that the Wine in a glass is pulled one way or the other by a miniscule fraction of a degree cannot affect its flavour, which is a function of its chemical composition. The ambient temperature might have an effect, both on people and on the fluid. The atmospheric pressure likewise - but that is less affected by the Moon than by weather patterns. In other words, its all rot.
Robert, Minster, Kent
If this article had appeared on April 1st it would have made for even lighter reading. As a wine merchant for over 40 years, this story ranks highly in the preposterous stakes. I have always prayed before running a tasting and I have never had a bad one yet, so I argue that a Christian perspective is the way forward....
Given that research has established that simply stamping a higher price on a bottle of wine improves its taste, it's hardly surprising that telling someone it's going to taste better on Thursday has a similar effect.
Ian Kemmish, Biggleswade, UK
This is very interesting and there is no doubt that the taste of wine is ephemeral and therefore metaphsyics probably play a part. but, atmospheric pressure as also mentioned above is key too. In this country we live 2/3rds of the year under low pressure and this can lead to wines tasting soupy and all rather the same sadly. Do you not find that all wine tastes better when drunk on French soil? Equally I recall being in a restaurant in the Alps with a Parisian friend and when it came to choosing the wine he was adamnant that it was not worth choosing anything too fine as the high altitude renders all wine towards the indifferent. So there are so many factors, but, that is what makes also for those fleeting incomparably memorable moments.
master of reality, London
I've read these moon theories, and watched my own organic garden to see if there are any observable traits. I put any improvement in horticulture down to simple TLC of the soil and plants. If you "dig" deeper into biodynamic ideas, you will find all kinds of weird stuff, like burying cows horns stuffed with their own manure. Many followers of Steiner's ideas believe in fairies and goblins, and unaccountable "energies". If all this were true, we'd know about it by now, but it all remains esoteric, and to gain the knowledge, guess what, you have to pay for it.
Alan Robinson, Bjerreby, Denmark