This is along the same lines as my previous post.
Its a fact that the orbit of the moon varies up to say 5000km during a normal monthy (28day) orbit of the moon - right? The perigee and apogee, (vertical position in reference to the equator), also vary during a 27 day cycle.
Its also a fact that the Sun also has a gravitational influence on our liquids but it is 2 1/2 times less than the Moon.
So if the moon can afect tides, by pulling water away from the earth due to gravitational influence, can it also affect our Hydrometer readings? Bear in mind that if the moon is pulling at our precious brew at the same force as the ocean, then our brew should be less dense right? If its less dense then our hydrometer will sink more, won't it? If so then we could be getting a false SG reading because the brew will appear a lower SG than it really is.
Lets say it's a Full Moon at its perigee in Cairns - Australia on Dec
22nd 2003, (its also a high tide), and we take a Hydrometer reading at Sea Level with Pressure 1010mb - and it reads SG 0.992, then what will the SG read when the moon is at is apogee on Jan 3rd 2004, at sea level, with the same atmospheric pressure? Might it read higher?I can hear many say - WHO CARES? But the reality is this, with many wines I have measured the same SG but with noticably slight variations in sweetness when tasting - even though I am using the same juice and methodology for winemaking and the same hydrometer. Some might put it down to variations in the actual juice and differences in yeast colony count, etc...
But could the relative local atmospheric pressure and Moon position influence the accuracy of my SG readings?
Cheers, Steve!