When wine tastes best

For me the answer is… root days!

And isn’t that what you might expect if you subscribe to a rather literal interpretation of the importance of terroir? Or could it just be that the whole idea is a load of bollocks? I am of course talking about the biodynamic theory that lunar cycles affect the taste of wine, fruit days being the most auspicious.

Here’s what I did to test the hypothesis. I analysed all 568 of my tasting note scores from last year. The scores range from 1 to 6, corresponding to the number of stars in my rating system. At the time of tasting I was unaware of the type of day. I used this 2009 biodynamic calendar for the analysis. I presume it is reasonably accurate. I did check a few days against another calendar, and they were in agreement. I have no idea at what time the type of day changes on any particular date, but as I could not find this information and very few people seem to care, I decided to ignore the issue. Most  wines would have been tasted at some time in the evening. If you want to reanalyse my raw data feel free. In the meantime, here is my summary of scores awarded on each type of day .

Mean Std Dev Number tasted
Fruit 3.02 1.209 94
Leaf 3.28 1.057 102
Root 3.30 1.020 184
Flower 3.09 1.125 188

So, if anything, I think wines taste best on root days, and worst on fruit days. But actually there are barely any significant differences at all. A one-way ANOVA test gives a p-value of 0.091 level. Or to put it another way, one would expect to get such a large spread in the means about one time in ten purely from random variation.

As far as I am concerned I got pretty much the results I expected, and I don’t feel any need to research this issue further.  To be frank I think I have already given this nonsense a lot more time than it deserves. However, if you have any more evidence to bring to light I’d be interested in seeing it.  But please – no more anecdotes about tasting wines when you were aware what sort of day it was.  And no half-baked argument along the lines of “if Tesco believe in it, there must be something in it”.  Hard data only.

Or perhaps you could explain from a theoretical point of view why this agricultural calendar has any relevance at all for wine tasting.  Why should fruit days be any better than, say, Fridays – which is when I think wine tastes best.

Author: Steve Slatcher

Wine enthusiast

One thought on “When wine tastes best”

  1. A few more comments on the significance of the results:

    1) Putting aside for a moment the concept of statistical significance, it is worth saying that the 0.28 point difference between root and fruit days is pretty large from a practical point of view. My points are quite coarse-grained, and it would proably mean an extra point being awarded or deducted for about a quarter of the wines.

    2) Researchers most commonly use 0.05 as the p-value level at which results are regarded as significant. The differences found were not significant at that level. However some use 0.10. Using that level they were just about significant, but of course not in the expected direction.

    3) Quite a lot of my notes are from tastings, and wines presented at any one tasting probably end to be of similar quality. My gut feeling is that this effect would tend to over-emphasis differences as measured by the ANOVA test.

    Finally, a note that I have no idea how many of the wines tasted were biodynamic. Most wines were available on the UK market, and most (over 400) were in the range £8 to £40 if that helps – your guess is as good as mine.

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