As I was helping out my Italian buddy make wine last evening, I was reminded of the days when my dad would warn me against interfering with wine on a full moon.

Ah yes! Leave it to the older-generation Italian home winemakers to add a dash of their “scientific knowledge” to winemaking: Some of it borders on the paranormal. And last time I checked, none were familiar with the work of Rudolf Steiner (Austrian philosopher and esotericist who founded biodynamic agriculture).

As the son of an Italian immigrant, a home winemaker too (of course), the fall season in Montreal was exciting for me—exciting for many reasons, but mainly because it was the start of winemaking season. I always enjoyed trekking to the local Italian market to buy what now seems like it was always Alicante (Alicante Bouschet) for red wine and Moscato (Muscat) or Thompson Seedless for white wine. There was something fun about buying grapes; perhaps it was because I knew that it would soon be transformed by some kind of magic into wine after I would develop blisters from working the hand-operated crusher, and the fact that I did not know the chemistry—and neither did my father—made the whole experience intriguing. And of course we would have friends and family over, and that meant party, food and wine, well, soft-drinks for us younger ones. But I digress.

Once the wine started fermenting and then “self-stabilized”—this generation of Italian home winemakers was very non-interventionist—it would then need at least one or two rackings and soon be bottled for drinking. And I remember my dad warning me against disturbing, as in racking, wine on a full moon or on a cloudy or rainy day. He never did offer me a convincing explanation except to say that it would make the wine turbido, or cloudy. I thought, is this some kind of witchcraft? I did learn though that you should never, ever, double-guess this “scientific” principle. Who knows? Maybe Steiner did align the planets and stars for my dad.

Only later in life as an avid winemaker myself did I decide to investigate this further, then armed with knowledge of chemistry, though “astropsychemistry” would have served better, if such a science existed. At first it made sense: On a full moon, the moon is closer to Earth and causes greater atmospheric pressure, which, in turn, causes greater pressure on wine in demijohns, and therefore causing suspended particles to agitate and wine to become cloudy. But then, this theory did not support the effects of a cloudy or rainy day, where atmospheric pressure is lower.

Based on my crude experiments, I could only conclude that there is no detectable difference between a wine processed during a full moon with one processed on a nice day. And now driven by financial and market pressures as a commercial winery operator, we never do worry about the weather or a full moon, that is unless we decide to take up biodynamic winemaking.