RomeoMike wrote:
> Will brass affect the taste of wine?

I can only guess, but I'd think so. I'd never heard of a historic
brass container for wine, so people must have known something. Brass
may not rust, but it has many different metals in it besides copper.
Some grades may even be toxic for long term wine exposure.

>Is air in the headspace of a
> secondary fermenter, if there is a lot of it, bad for the wine?

If you sulfite properly so that vinegar bacteria can't grow, then too
much of an airspace could give a wine too much of a "sherry-like"
character. Which may not match whatever flavors in the wine you're
going for.