What??? Where that was born cannot be fully explained. Just like most myths, the black cat's path, walking under the ladder, passing a cemetary, friday the 13th etc. Myths have the habit of lasting for centuries and as we all know, they are very persistent.
Fortunately an amateur winemaker did some in depth research on the above mentioned myth. He found that on a full moon the earth's atmospheric pressure is normally lower: 100-101. That means any gases in fermenting wine will flow out more easily, thereby increasing visible activity. Fermentation produces gases, mainly CO2. When the pressure gets higher, the ability of the gases to escape is reduced.
We have had phone calls which said 'my beer is at 1.006 and its still bubbling'. Of course we then explain that the bubbling is simply the gas escaping the liquid, and the low pressure system which is making it rain that day causes an increase in the rate of the escaping gas (i.e. bubbling).
And it makes perfect senese. Has anyone heard of a high pressure storm? No – wind velocity is the culprit. The recent Arthur tropical storm was a low pressure system and it was still causing havoc days later.