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.
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.