Headspace and Red Wine

Hello Everyone! This is my first post on this forum, and I have a question about how much headspace you need for red wine. I’m also new to the hobby, so forgive my misuse of terminology if that happens. Here’s my situation:

I have a 2010 Syrah quietly resting in my basement. I pressed the grapes back in October and placed the wine into a 6.5 gallon carboy. After the solids settled out and malolactic finished, I racked it again into a 5-gallon and 1-gallon carboy. Now I’m looking at a second racking and only have my 6.5 gallon carbon handy and am worked about the 0.5 gallon of headspace. I know a little oxygen is good for reds, but will this be too much? The siimplest solution would be to go buy a 6-gallon carboy, but I'd hesitant to push my wife's buttons any further. ;-)

Any and all help is greatly appreciated!

I would rack tthe 5 gallons into the 6.5 gallon, then the gallon jug ontop of that. Then clean and sterilize the 5 gallon carboy and rack as much of it back into the 5 gallon carboy, right up to the neck. The rest you could split between a couple large wine bottles or other vessle.

You want almost NO headspace- you want to top up to within an inch or two of the bung. The headspace with .5 gallon short will be all the way across the carboy- way too much.

You can use a smaller carboy, and a couple of wine bottles (they take a smaller stopper, but you can get them at wine supply stores for under $1) for the excess.

Don't ruin your wine because you can't afford another carboy!

Thank you both for the input and suggestions. My gut was telling me there wouuld be too much air, but I wanted to make sure.

You could always top off with a similar tasting wine if you don't mind a blend.

Half a gallon out of 6 is only around 9%

someone told me a little while back you can fill the space with those glass stones used in fish tanks.

marbles work too, so do oak cubes or spirals