Time to leave the biodynamic calendar behind? Wine tastes the same on fruit and root days

wine science

Time to leave the biodynamic calendar behind? Wine tastes the same on fruit and root days


There’s been a lot of talk about the biodynamic calendar in the wine trade. At wine tastings, it’s not unusual for tasters to start muttering that the wines aren’t showing very well. Then someone whips out their smartphone. ‘I thought so!’ they proclaim. ‘It’s a root day.’

For those unfamiliar with the concept, I’m referring to the biodynamic calendar first developed by an Austrian, Maria Thun (1922-2012). She devised this planting and sowing calendar after she was introduced to the biodynamic farming ideas of Rudolf Steiner in the 1940s.

It uses the relative positions of the moon with regard to the constellation of the planets to determine which days are fruit, root, leaf and flower. As well as being used to time interventions in the vineyard and winery, this calendar is also used as a guide to when wine tastes best. Ideally, you want to drink wine on a fruit/flower day and not on a root/leaf day. Floris publishes an annual version of the Thun calendar as a small book titled When Wine Tastes Best, which is also available as an app.

So established is this notion in the wine trade that many of the leading UK supermarkets use Thus’s calendar to determine when they hold their press tastings.

There have been several informal, small scale tests of the calendar, but these haven’t had the necessary rigour to provide any significant results. But a study just published, led by two very well known researchers, Wendy Parr and Dominique Valentin, has subjected the notion that the biodynamic calendar affects the taste of wine to a proper scientific examination. It shows quite clearly that root days and fruit days have no effect on the way wine tastes.


Expectation or Sensorial Reality? An Empirical Investigation of the Biodynamic Calendar for Wine Drinkers

Wendy V. Parr , Dominique Valentin, Phil Reedman, Claire Grose, James A. Green

The study’s aim was to investigate a central tenet of biodynamic philosophy as applied to wine tasting, namely that wines taste different in systematic ways on days determined by the lunar cycle. Nineteen New Zealand wine professionals tasted blind 12 Pinot noir wines at times determined within the biodynamic calendar for wine drinkers as being favourable (Fruit day) and unfavourable (Root day) for wine tasting. Tasters rated each wine four times, twice on a Fruit day and twice on a Root day, using 20 experimenter-provided descriptors. Wine descriptors spanned a range of varietal-relevant aroma, taste, and mouthfeel characteristics, and were selected with the aim of elucidating both qualitative and quantitative aspects of each wine’s perceived aromatic, taste, and structural aspects including overall wine quality and liking. A post-experimental questionnaire was completed by each participant to determine their degree of knowledge about the purpose of the study, and their awareness of the existence of the biodynamic wine drinkers’ calendar. Basic wine physico-chemical parameters were determined for the wines tasted on each of a Fruit day and a Root day. Results demonstrated that the wines were judged differentially on all attributes measured although type of day as determined by the biodynamic calendar for wine drinkers did not influence systematically any of the wine characteristics evaluated. The findings highlight the importance of testing experimentally practices that are based on anecdotal evidence but that lend themselves to empirical investigation.

Full paper is available here.

It’s a carefully done study, and takes into account many confounders. For example, the authors checked that the tasters weren’t aware whether it was a root or fruit day. They also used wines that were from grapes that were conventionally farmed and biodynamically farmed (some might expect biodynamic wines to be more responsive to lunar cycles, for example).

These results don’t suggest that a Thun app wielding believer would see no effect of root days or fruit days on wine. Top-down cognitive effects are quite powerful, as the authors point out in the paper. If you believe it is a fruit day, and believe in the biodynamic calendar, a wine might well taste better to you than it does on a root day. Knowledge shapes perception in powerful ways.

Will this stop people using the biodynamic calendar? I doubt it. If we change our beliefs, it is rarely because someone has presented us with facts.

Also, this doesn’t call into question other aspects of biodynamics, which have a much stronger theoretical basis. Neither does it say anything about using the calendar for planting or other activities in the field. It just shows that lunar effects don’t affect the way that wine tastes.

24 Comments on Time to leave the biodynamic calendar behind? Wine tastes the same on fruit and root daysTagged ,
wine journalist and flavour obsessive

24 thoughts on “Time to leave the biodynamic calendar behind? Wine tastes the same on fruit and root days

  1. Wines also taste the same on Mondays when most people are unhappy and on Fridays when most people are happy! IMO, wine tasting is so subjective that any effort to try to be ‘objective’ or ‘scientific’ about it has to be taken with a great deal of salt.

  2. I fully believe in the calendar. However, with that said, I do not apply the calendar to wines I do not have a multitude of experience tasting. I’ve encountered people you describe in the first portion of your piece, and they are idiotic.

    I have a large library of wines from Graziano Family of Wines in Mendocino. I have had their wines more times than I can count, and I KNOW when a fruit day is upon us. I will sup, know, and confirm.

    However, if I open a Ceretto single vineyard Barolo I’ve never had, I’ll drink that bitch regardless of the day, simply bc I don’t “know” the wine intimately, and you cannot know a wine that intimately unless you’ve had it a dozen times or more!


  3. Interesting. When I attended agriculture college in the Netherlands which had
    a biodynamic run farm and garden on site. We ran a test to show the benefits of using Maria Thuns calendar.
    It was well run, in a greenhouse to limit weather factors. Soil, moisture and light were as similar as doable. Radishes were planted on root, fruit and leaf days. In the end the different plant parts were weighed and measured.
    The results: We could have written a new calendar!!nothing turned out as it should have been. So there you go.
    Maybe the glass of the greenhouse distorted the cosmic rays???

  4. Yes, but did they control for people who actually believed in Biodynamics? Maybe the calendar only works for true believers. Kind of like the eucharist?

  5. Also, this doesn’t call into question other aspects of biodynamics, which have a much stronger theoretical basis.

    Jamie, I am interested in what the stronger theoretical basis is?

  6. Well this is actually welcome news. I’ve been using this calendar throughout 2016 and whenever I planned to open a really good bottle I would always check to make sure it wasn’t a root day. To be honest It was starting to become a bit of a drag. I can now open bottles when I want – great.

  7. The probable use of sulfites will strongly influence the stability of wines on these days. The ignorance of that in the study is unfortunate.

  8. People also believe that if they are born in the same months, they will have similar personalities. “Ah, yes you’re a libra, it all makes perfect sense now…”

  9. This is a good time to remind people that R.Steiner was a teetotaler and knew nothing about wine.

  10. It’s an admirable study and well summed up, Jamie.

    However, but I’d be intrigued to see the exact same study re-run using Burgundy Pinot Noirs instead and also noting the total and free SO2 levels – I agree with the comment of Gus above that this might make a difference.

  11. Gus and Wink: Both conventionally- and biodynamically-produced wines were included in the study, so a broad range of total and free SO2 would have been present in the wines used and still no correlations with the calendar were detected. What’s more, most of the variation in tasting results occurred between the multiple tasting of the same category of day (e.g. differences from one fruit day to another), demonstrating that something influences our impressions of wine from one tasting to another, but it’s not the position of the moon relative to the constellations.

  12. Hi Jamie,
    We tried a very unscientific and informal trial at Waitrose a few years ago, and couldn’t find any correlation, so we never used the biodynamic calendar to choose our tasting dates (while I was there anyway…).
    But it does seem true that often a bunch of tasters who know the wines well can taste the same wines on different days, and feel that they show differently. If this is a true effect, then it must be another variable. One candidate could be atmospheric pressure. It is alleged that reds taste more tannic and less fruity on a descending barometer. Any thoughts?

  13. I agree with Gus and Wink. It would have been useful to include “natural” wines in the study. Biodynamically raised grapes mean nothing if the wines are filtered, sterile filtered or otherwise stabilized. I have no dog in this fight, I just want to be clear that this study only pertains to conventionally produced wines, some of which are processed into inertness.

  14. I think it would also have been useful to include wines that had been buried in cow dung for six months. And it goes without saying that sterile conventionally produced glassware refracts the light ether in a way that cuts off the upper reasoning part of the brain from the lower sensual part of the brain thus rendering judgement impossible. You can read more about this here: http://rsquotes.blogspot.fr/search/label/astronomy.

  15. Sort of thinking down the same lines as Dennis, Gus and Wink… It would be really interesting to see this test done with a range of different wines, across the spectrum of ‘conventional’ and ‘natural’ from different countries, different styles etc.
    Pinot from NZ is a bit narrow methinks! Having said that, when working in the on-trade in the UK, the calendar was referred to quite regularly. Since switching from London to Stockholm, pretty much never and that is not due to less ‘believers’ as such.

  16. I think Justin has a good point, barometric pressure may have something to do with it. Certain airlines even hire sommeliers to decide what wines taste good at 38000 feet, cabin pressure usually equal to 6000 or higher feet above sea level.

  17. I took pains to read the data-thick report and found this to be a futile attempt to disprove the usefulness of the calendar. In “Sensory Data”, it mentioned: “For the other two significant effects, oak integration was higher on a Root day and bitterness was higher on a Fruit day, these two effects being counter to the biodynamic calendar prediction and anecdotal evidence that the wines would taste “better” on a Fruit than Root day. ” But the calendar does not preduct that wines would taste better on a Fruit day. The wine just shows itself differently. A root day displays more minerality, and a fruit day more fruit. Some prefer minerals to fruit, but some like fruit better. Try tasting a hot vintage like 2003 on a Leaf day, and you will be amazed how elegant it can be. Leaf sometimes does taste better than Fruit, at least to some palates that prefer a more balanced or elegant wine. I wonder if the author of this piece has tried the same wines on different days and discovered for himself what a difference it makes.

  18. One has also to look to Astronomy models in all of this. According to some sources the Western model is quite “off “ the real times when it comes to the moon being in a sign. Vedic astronomy/science is a much older model than western astronomy and if you challenge the Buffs here, for me they have no answer. How come the Indian Biodynamic Association has different times on their Calandar?? because they believe the Western calander is off and they stick with traditional vedic science. This also concurs with the“Thun“ calander for years and found its timing to be poppycock. All I have to do is go out in my garden today, and sense nature, its a beautiful day, sunny, which is an exception in Ireland, and my bees are going mad with activity. Its mid February! The Thun calandar says its a “leaf day“, the indian BD calandar says its a “fruit day“!! . I know its a fruit day in my bones! Its 20-2-18 now at 2.17pm.

  19. Justin and John,
    Barometric pressure has nothing to do with biodynamic calendar, because it has nothing to do with full moon or new moon, it only relates to where moon located on the sky arch – actually it’s astrology sign. When it’s fire sign houses (Aries, Leo…), it’s fruit days.

    Gus, Wink and Dennis,
    Biodynamic wine is included in this study. BTW, even if your arguement is true, then it would mean that biodynamic calendar only applies to biodynamic wine, any wine with reasonable amount of SO2 is free from moon’s influence, then the calendar is pretty much useless for most of wine drinkers around the world. It will then only apply to people who believe in biodynamic, which is probably already the case now.

  20. I’m glad to see someone test this, BUT, there is one major flaw in the design. I find it laborious for one to know whether a wine is tasting good or not unless one has intimate knowledge of that wine. Winemakers, importers (myself) drink the same wines on a continuous basis. You have to know a wine inside or out before you can render judgement as to whether is off. I’ve had days where I’ve had 10 wines open and they were all off – for me that is too big to be a coincidence.

    It doesn’t matter how experienced of a taster one may be…..without really knowing the wine (which would mean tasting dozens of times…if not more), how could one render judgment ? Winemakers are the best source because they are constantly tasting it and I’ve documented numerous counts of how the wines are always all over the place. For me, off days are not so obvious, but very subtle that most people would not pick up on.

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