Rich,
A good wine takes more than a couple of months to age well, after
fermentation is complete, as compared to beer which may only take 2-3
weeks( depending on if you 're making a lager or ale).
O2 can really affect the color, taste, and feel of both beer and wine, but
the length of aging required for wine makes it a target for oxidization
problems which is why it needs to be topped up.

Hope that explains it a little


--
Roger & Lynda

"Rich" > wrote in message
om...
> I have made a few batches of beer and want to try a wine. I'm a
> little confused about the procedure. It appear that it is recommeded
> to top off in the secondary, why? Is wine that much more sensitive to
> oxidation than beer? The few books I looked at all seem to guess when
> fermentatiopn is done, cannot you use a stable SG as a sign that it is
> done? Look forward to your insights.