RJ Spagnols Controlled oxygen exposure during bulk aging

[don67]

Hi all,

During a recent Niagara wine tour I was surprised to learn that the commercial wineries leave a lot of air space in the oak barrels while aging red wine. The barrels are maybe 3/4 full of wine, in contrast to kit winemaking where topping-up is practically a religion. Even the oft-quoted Jack Keller advocates topping-up.

What gives? Does the difference lie in sulfite concentration? Something to do with malolactic fermentation? I can't find the answer anywhere, so before my curiosity drives me to do something stupid with my next batch of wine (like bulk aging in a half-empty carboy) I thought I'd ask if anyone has any experience in this area.

Don

 

[Runningwolf]

Don I rarely top up barrels unless if we remove the bung. When I do remove a bung there is such a sudden whoosh of air as the barrel has created it's own vacuum. once the bung is removed and the vacuum broken I top up.

 

[SouthernChemist]

How big are the barrels they were using?

 

[don67]

They were large barrels... approx 10x the typical wine kit volume, ie: 200-300 litres.

Dan, I'm guessing that vacuum is unique to barrel aging(?). Never noticed a vacuum when using glass carboys, except when there's sulfite solution in an empty one.

 

[Boatboy24]

Don I rarely top up barrels unless if we remove the bung. When I do remove a bung there is such a sudden whoosh of air as the barrel has created it's own vacuum. once the bung is removed and the vacuum broken I top up.

That's interesting, Dan. I've often wondered how commercial wineries can top up barrels when they have racks and racks of them.

 

[SouthernChemist]

They were large barrels... approx 10x the typical wine kit volume, ie: 200-300 litres.

Dan, I'm guessing that vacuum is unique to barrel aging(?). Never noticed a vacuum when using glass carboys, except when there's sulfite solution in an empty one.

You can get one due to temperature differences (the air inside of the carboy/barrel is affected by the temperature of the wine, for example) or just typical pressure changes due to weather. This is all provided your airlock/bung is secure. The headspace volume inside of a barrel is probably larger than the headspace volume inside of a topped carboy, though, and so the pressure difference is more noticeable with a barrel (or empty carboy).

 

[don67]

I guess the negative pressure serves a purpose; to draw in trace amounts of oxygen through the oak and thus enhance the wine's maturity. Obviously this is not possible with a carboy, which probably explains why the kit manufacturers don't recommend air space... too much risk for not enough reward. Wine kits are all about consistency, after all.

My conclusion is that giving the wine a little air exposure is probably desirable if the goal is to maximize enjoyment within 1-2 years. But I'll probably limit myself to a little splashing during rackings, and maybe a little air space during clearing.

Thank you all for the comments.

Don