Can I vacuum my primary fermenter headspace for an extended period?

Question

I have a 12 gallon stainless steel vessel with 10 gal. of pinot noir in it. I racked it once and it has been sitting for 6 months or so.

I keep the 2gal of headspace full of CO2. Everything seems to be going very well - I tasted it recently and I think it's ready to bottle. (months overdue, actually)

The only minor problem is there seems to be some CO2 still dissolved in the wine, which makes sense.

So, I got a brake bleed kit and will make a vacuum and let all the carbon dioxide bubble out. I read that it only takes 5-10 mins at vacuum for the CO2 to bubble out.

My question: Can I just set the vacuum and leave it for one or two or five days until I am ready to bottle ? Is there anything at all wrong with replacing the headspace with a vacuum for an extended period of time ?

Next year, when I do this again, can I just skip the CO2 blanket and keep the the wine under vacuum at all times ? This is after all fermentation is done and we're just letting it sit on oak cubes or ... we're just too busy to bottle it so it needs to sit ... any problem just being under vacuum all the time ?

Thanks.

Answer 1

FWIW, you should realize that the CO2 you are degassing does not come from the blanket of CO2 in the fermentor. Its CO2 that dissolved into the wine during fermentation. I find the vacuum idea a cool way to degas though.

In the future, I think your process needs to stay the same for using CO2 to keep the headspace free from O2. As for keeping it under vacuum I see two issues. You need to be 100% sure you're vessel can with stand the vacuum for that long. It might be OK for the degas but the fermentor might implode if given too much time or the temperature drops enough to pull more vacuum. Second, you need to be 100% certain your lid can maintain the seal while under vacuum. Otherwise, that vacuum will pull in air and O2.

You can remedy both issues by simply degasing as you have. Leave a blanket of CO2 until you bottle. Any CO2 absorbed from the blanket (minimal at best) will likely be degased out of solution when racking into bottles.

I am not a dedicated wine maker but that's the way I see it from what I know about CO2 and pressures. I've made a few batches of wine FWIW.