What Is Biodynamic Farming?
Biodynamic agriculture is one of the oldest and most rigorous forms of organic farming. Developed in the 1920s by Austrian philosopher Rudolf Steiner, it treats the farm — or in this case, the vineyard — as a self-sustaining ecosystem, deeply connected to cosmic rhythms including the movements of the moon, sun and planets.
Where organic farming eliminates synthetic pesticides and fertilisers, biodynamics goes several steps further. It prescribes specific preparations made from fermented plant and animal materials, timed applications based on the lunar calendar, and a philosophy that views soil health as the foundation of wine quality. The term "biodynamic wine" refers to wine made from grapes grown under these principles.
In the wine world, biodynamics has moved from fringe to mainstream. Producers including Domaine Leflaive in Burgundy, Nicolas Joly in the Loire Valley, and Benziger Family Winery in Sonoma have adopted biodynamic certification. The governing body Demeter International certifies biodynamic farms across more than 60 countries.
"Biodynamics treats the vine and the land as a single, living organism — one that breathes with the seasons and responds to the movements of celestial bodies."
— Nicolas Joly, Biodynamic pioneer, Coulée de SerrantCentral to the biodynamic approach is the biodynamic planting calendar — a document published annually that designates each day as optimal for specific farming tasks based on the moon's position in the zodiac. This same calendar, popularised by Maria Thun, is what wine drinkers consult to decide when to open a bottle.
Who Was Maria Thun?
Maria Thun (1922–2012) was a German biodynamic researcher who spent more than five decades studying how lunar and planetary cycles affect plant growth. Beginning in the 1950s, she conducted systematic planting experiments — sowing the same crops on different days and carefully recording the results. Her conclusion: the moon's position in the zodiac significantly influences plant vitality, root growth, leaf development and fruit production.
Her annual Sowing and Planting Calendar, first published in 1963, became the definitive biodynamic farming guide. It divided each day into one of four categories — fruit, flower, leaf and root — based on which zodiac constellation the moon was passing through. Fire signs (Aries, Leo, Sagittarius) became fruit days. Air signs (Gemini, Libra, Aquarius) became flower days. Water signs (Cancer, Scorpio, Pisces) became leaf days. Earth signs (Taurus, Virgo, Capricorn) became root days.
Thun never specifically set out to create a wine-tasting calendar. The application of her planting system to wine drinking was a natural extension, popularised by biodynamic winemakers who noticed that the same lunar energies that affected vine growth also seemed to influence how wine opened in the glass. Her son Matthias Thun continues publishing the annual calendar, and separately publishes When Wine Tastes Best — a dedicated guide for wine drinkers based entirely on her original research.
The Four Day Types — Fruit, Flower, Leaf & Root
The biodynamic calendar divides every day of the year into one of four categories. Each corresponds to a part of the plant — and a quality of experience when drinking wine.
The key distinction for wine drinkers is simple: fruit and flower days are good; leaf and root days are bad. On good days, wine is said to be "open" — more aromatic, more complex, with better balance. On bad days, wine is "closed" — muted, harsh, or simply disappointing relative to its potential.
The classification of each day depends on which zodiac sign the moon is transiting. Because the moon moves through all twelve signs roughly every 27 days, each sign gets approximately 2–3 days of influence before the moon moves on. The result is a pattern of good and bad days that cycles through the month — never too long a gap between fruit days, but never guaranteed clustering either.
The Moon Through the Zodiac
Thun's system does not use moon phases. It tracks the moon's position against the twelve zodiac constellations (the sidereal zodiac). Each constellation corresponds to one of the four classical elements, and each element governs one day type.
The moon completes a full circuit of the zodiac every 27.32 days (the sidereal month), passing through each constellation in roughly 2 to 3 days. This means the four day types cycle through the month in a repeating pattern, giving fruit, flower, leaf and root days at fairly regular intervals — regardless of the moon's phase.
| Constellation | Element | Day Type | Wine Quality |
|---|---|---|---|
| ♈ Aries | Fire | Fruit | Excellent — wines vivid and open |
| ♉ Taurus | Earth | Root | Poor — wines closed and tannic |
| ♊ Gemini | Air | Flower | Good — aromatic whites shine |
| ♋ Cancer | Water | Leaf | Avoid — wines muted and vegetal |
| ♌ Leo | Fire | Fruit | Excellent — the best day for reds |
| ♍ Virgo | Earth | Root | Poor — wines feel earthbound |
| ♎ Libra | Air | Flower | Good — elegant, perfumed wines |
| ♏ Scorpio | Water | Leaf | Avoid — aromatics suppressed |
| ♐ Sagittarius | Fire | Fruit | Excellent — full-bodied wines sing |
| ♑ Capricorn | Earth | Root | Poor — tannins tight, finish flat |
| ♒ Aquarius | Air | Flower | Good — champagne at its best |
| ♓ Pisces | Water | Leaf | Avoid — wines closed and quiet |
Because the constellations are unequal in size, the moon spends slightly more time in some (Virgo, Pisces) than others (Cancer, Capricorn). Thun's published calendars account for this by using the International Astronomical Union (IAU) constellation boundaries rather than the equal 30° divisions of tropical astrology. VinoLuna uses these same real IAU boundary crossings — not equal 30° segments — so a fruit, flower, leaf or root day here lines up with Thun's published calendar to the hour, not just the day.
Note that many biodynamic wineries treat the moon's phase as a secondary signal — some enthusiasts prefer opening wine near a Full Moon regardless of the constellation. But in Thun's original framework, the constellation is the primary determinant. That is the system VinoLuna implements.
How to Use the Biodynamic Calendar for Wine
Using the biodynamic calendar for wine is refreshingly simple once you understand the framework. Here's how to get started:
1. Check the day type before opening a special bottle. If you have a wine you've been saving — a fine Burgundy, a good Barolo, an aged Riesling — check the calendar before you open it. If it's a root or leaf day, wait. Fruit and flower days come around every few days, so patience is rarely tested for long.
2. Plan wine dinners on fruit days. If you're hosting a wine dinner, tasting, or any occasion where the wine matters, choose a fruit day. Check VinoLuna a week in advance and schedule around the lunar cycle. This is exactly what major UK retailers and wine merchants do before their press tastings.
3. Use the dial to explore future days. VinoLuna's interactive dial lets you scroll forward through days to find the next fruit day. If today is a root day, you might find a fruit day just two days ahead — a useful guide for when to pull a cork.
4. Trust your own experience. Keep a simple log. Note the day type when you open wine. Over time you may start to notice patterns — or you may find no difference at all. Either outcome is valid. The biodynamic calendar is a tool for mindful enjoyment, not a rigid doctrine.
"A root day won't make a good wine taste bad, but on a fruit day the wine is almost leaping out of the bottle."
— David Motion, The Winery, London (via The Telegraph)What Does the Science Say?
The biodynamic calendar sits in genuinely contested scientific territory — and that's what makes it interesting.
The most rigorous study to date was published in 2016 by Wendy Parr and Dominique Valentin, two respected sensory scientists. Nineteen New Zealand wine professionals tasted Pinot noir blind on designated fruit days and root days, rating each wine four times. The result: no statistically significant difference in scores or descriptors between fruit and root day tastings. The paper concluded that the calendar's effect on perception is most likely driven by expectation rather than measurable sensory change.
Critics of the study note its small sample size and the controlled lab environment — conditions quite different from a real cellar tasting. Advocates point to the genuine difficulty of controlling all variables: bottle variation, serving temperature, the tasters' prior knowledge of the calendar, and the multi-day gap between comparative tastings.
What science does confirm is that expectation powerfully shapes perception. If you believe a wine will taste better on a fruit day, it very likely will. This isn't fraud — it's the placebo effect working in your favour. Any tool that helps you approach wine with more attention and intention is probably making your experience better, regardless of whether the moon is involved.
Meanwhile, several aspects of biodynamic farming — particularly the emphasis on soil health, biodiversity and reduced chemical intervention — have robust scientific support. The quality credentials of many biodynamic estates suggest that something about the practice yields excellent wine, even if the exact mechanism remains debated.
Wineries & Retailers Who Use the Calendar
The biodynamic calendar is no longer the preserve of alternative winemakers. It has been adopted across the full spectrum of the wine industry — from small natural wine producers to major supermarket chains.
In the UK, Marks & Spencer and Tesco have both been reported to consult the biodynamic calendar when scheduling their press wine tastings — a remarkable adoption of an esoteric farming philosophy by mainstream grocery retail. The reasoning is pragmatic: if the calendar affects how critics perceive wine, scheduling tastings on fruit days gives products the best possible chance of a positive review.
Demeter International is the primary certifying body for biodynamic agriculture globally, with certified estates in over 60 countries. The Biodyvin association focuses specifically on biodynamic winemaking in France and operates with arguably stricter standards than Demeter's wine certification.