>
> I suppose both concerns (oxidation and thermal expansion) could be
addressed
> by using a larger airspace and filling it with CO2 upon racking?
>
>

CO2 will not be effective for long term storage (more than 2 or 3 days at
best). Personally, if I'm blanketing a tank, it goes no more than 24 hrs
without regassing.

I have no refrigeration, but a decent, true cellar in a full, 4 season
climate. There's still a significant amount of air transfer from
temperature fluctuations (55 to 65F), so no inert gas is going to be
effective, on it's own, without some kind of maintenance to replenish the
gas.

Not sure how to describe the headspace I leave beyond "minimum". In tanks,
depending on size/shape, that usually means about 2 inches. Think of a wine
bottle. That's about the right proportion of headspace. They are designed
to take a temperature fluctuation and minimize the exposure of gas to the
wine.


clyde