I've got a 50 litre barrel that I have a Cabernet in. I put a second
run wine through the barrel before putting in the cabernet so I could
get the initial oak out. Now I have my cabernet in it and it is doing
fine. MLF is over, the wine is sulfited. I have to add around 50 ml
of wine every week to top up. I am using bottles of raw cabernet that
I keep in screwtop bottles. This wine is pretty heavily sulfited so
slow oxidation but there is alot of head space in the bottle. I use
this bottled wine for top up for 6 weeks or so.

I've noticed a faint white ring in the bottle at the top of the wine.
It smells fine. Am I endangering the wine by keeping my top up this
way? I can't open a finished bottled wine every week for top up, I
don't have enough. Can I keep this heavily sulfited wine around for
that long without harm? How do you manage the top up for small
barrels? If I had a larger barrel and was adding a bottle a week, that
would be fine, but I'm using just small amounts. How do I manage this?

Thanks in advance

Dan