4 gallons wine...can i rack to 5 gallon if...?

I just made my 3 batch of wine ever and it is my first batch made from fruit. For some reason I did a 4 gallon batch. I dont have a 3 gallon carboy but have 2 5 gallons. I dont want to spend 25$ buying a 3 gallon when i probably wont use it much in the future. right now it is done fermenting and needs to be racked. I know you are suppose to have very little head space when you rack, due to oxygen. I was hoping to rack to a 5 gallon carboy and drop a chip of dry ice into it and put my air lock on it and let the dissolving dry ice push out the oxygen and replace it with CO2....would this work?...whats your opinion?
Thanks
Robert

Robert,
IMO, I would get a couple of 1 gal. glass jugs and put the excess in those. The dry ice idea may work for a while, but every time you want to rack you'll need to buy dry ice again. I have a CO2 tank that I use to temporaily lay down a blanket of CO2 and it seems to protect my wine for a month or so (I've never had any to oxidize), but I replace the blanket every few weeks just to be on the safe side. Long term, I always try to use the proper carboy size or put any reserve in a glass jug.

BTW, welcome to the forum!

Fred

Ive never used dry ice to do this so cant make a recommendation on it. Id get a 3 gallon and a 1 gallon jug as they come in handy all the time especially if you want to make a specialty win e where 5 or 6 gallons is just too much like a Port. O sometimes use my 2 3er's for splitting a red wine into 2 and oaking them differently or a white and sweeten only 1/2.

if I did take the chance and use the dry ice....is there any way of telling that the wine has been oxidised rather than tasting?...that is, is it visible? I also dont know if this makes any difference but the wine is blueberry, made from frozen fruit

It will develope a brown color and off taste! A white wine will become very evident very fast.