Beer and wine are different, you really do not want that headspace
after fermentation is complete with wine.

Wine ages much longer than beer normally, especially reds. That makes
it more suseptible to oxidization over time. You do not want to
depend on CO2 from fermentation as a gas blanket since it really has
to saturate the wine to be effective, once you rack it gets a bit of
air in it. You rack a few times with wine, usually once with beer.

If you have a tank of CO2 from beer making that can work, but I can't
really advise you on how long to bubble it through. Most people use an
inert gas, I see nitrogen and argon used. Anything that displaces all
of the oxygen should work. They make gas dispersion tubes for this if
that is the route you want to go. I am not speaking from experience
since I top up.)

6 gallons to start will work out to 5 to 5.5 gallons of finished wine
once you rack a few times. Most winemakers either top it up with
other wine (you could use a bag in the box) or use smaller containers.
I top up to 1/2" from the airlock. I use 3 - 6.5 gallon carboys, but
most of mine are 5's.

Regards,
Joe

> Miker wrote:
>
> > Nothing wrong with fermenting in the 6 1/2, but once you start aging
> > and such you'll need to eliminate that air space...

> I still do not understand the reasoning behind .5 gallon of space being a
> problem if it's filled with CO2.