Headspace after primary fermentation.

[ricchezza]

Hello. I’m posting because I’ve been searching the forums and not quite getting the info I’m looking for.
I’m currently in primary fermentation of my first wine; a Malbec from 6 gallons of fresh juice. Upon searching the net for wine making info one thing is clear: absolute minimal headspace in during secondary and subsequent aging. That is assuming that my transfer fits perfectly into one of my 5, or 6.5, gallon carboys. I do not want to top off with another wine and dilute this batch.

The question that brought me here is what are your thoughts on topping off the carboy headspace by purging with food grade CO2 regardless of actual space?

I’m asking to generate discussion here and see how others react. Applying what I’ve read here and elsewhere, and applying 10+ years of home-brewing experience, it would seem to be the the wine would be fine. The CO2 will purge the oxygen from the carboy. I figure (and this is where I’m looking to experienced vintners) natural degassing will push excess CO2 out of the airlock, rather than absorbing (like long term aging beer).

 

[jgmann67]

Whether you go with co2 or top off with a similar wine (really, 100 ml to get you home isn’t going to change the character of your wine in any way that you’ll notice), you’ll land at the same place... finishing up with a secondary ferment, racking off the lees and trying to figure out what to do about headspace all over again.

But, with either method above, I think your wine will be safe.

 

[AZMDTed]

Welcome. I know you didn't ask this but I think your assumption is off a bit. It is not critical to have minimal headspace in secondary. In secondary you will still have plenty of naturally outgassing CO2 to provide the protective cap. You will also want your wine to have some oxygen to keep the yeast alive until they've done their duty. No need for topping off or purging in secondary. After that, then yes, headspace becomes an issue that you will want to address.

There has been several discussions on here about using CO2 in the headspace. Most wonder why you add the gas the rest of us are trying awfully hard to get rid of, while others say they use it with no issues. There are other inert gasses that are more commonly used that avoid that debate, but since I just top off with another wine I really don't have an opinion on what gas is best.

 

[Smok1]

I use nitrogen, just because air is 80% nitrogen/ 20% oxygen, so basically shouldnt leave any off tastes, but i dont think using co2 would be an issue, the co2 were trying to get rid of is the suspended co2 in the wine itself, covering the wine with co2 should be ok id think.

Actually after checking the specific gravity of both nitrogen and co2, co2 may have an advantage over nitrogen in the fact that its sg os 1.5, so its heavier than air, so it would carpet the wine a bit better than nitrogen which has an sg being just under 1.000 and the oxygen has a sg just over 1.000, so technically if i didnt make sure i purged all the air out of my vessel with nitrogen and some oxygen remained the oxygen would work itself to the wine.

 

[NorCal]

Or use a one way valve and evacuate the space with a vacuum pump. I do this to partially filled carboys for months at a time with no noticeable impact to the wine.

 

[Smok1]

Or use a one way valve and evacuate the space with a vacuum pump. I do this to partially filled carboys for months at a time with no noticeable impact to the wine.

Where did you get the one way valve?

 

[bkisel]

Welcome to the forum!

Like already mentioned secondary head space shouldn't be an issue if your batch is locked down - sealed lid and air lock.

After secondary a nicely sized carboy and like wine to top off do the trick for me.

 

[Ajmassa]

Another Quick and easy diy is to use a VaccuVin meant for keeping an opened bottle of wine longer. And gypsy rig a stopper to fit a bung (I drilled out solid bungs to accept). Some stoppers already fit the universal bung. Pump out the air with the vaccuvin - no more headspace issue. And just repump weekly to remove any air possibly seeing in.


Or the headspace eliminator. Which has been a headACHE eliminator for me. No more messing with different Diys. And the baby "snot" pump collapsed acts as a visual tool to know you've still got vacuum pressure. Used with the AllinOne vacuum pump from the same seller, who is an active contributing member on this forum. I need to order a couple more actually.

https://www.allinonewinepump.com/product/headspace-eliminator/

 

[sour_grapes]

Actually after checking the specific gravity of both nitrogen and co2, co2 may have an advantage over nitrogen in the fact that its sg os 1.5, so its heavier than air, so it would carpet the wine a bit better than nitrogen

Once again, PSA: there is no "blanketing effect." Gases mix freely on the timescale of tens of seconds.

if i didnt make sure i purged all the air out of my vessel with nitrogen and some oxygen remained the oxygen would work itself to the wine.

Yes, that is correct, any oxygen left will have free access to the wine.

 

[Smok1]

Once again, PSA: there is no "blanketing effect." Gases mix freely on the timescale of tens of seconds.




Yes, that is correct, any oxygen left will have free access to the wine.

There must be an exception to the blanketing effect because i install commercial CO/propane detectors at work and gas code calls for the propane detector to be placed 1” from the floor and the CO to be mounted at 5”, so vapor propane has an sg of 1.52 and it settles on the floor of parkades, which is why its a bigger hazard than natural gas which has an sg lower than air and dissapates rather than settles. Co detectors are placed at 5” because its sg is so close to air that code states it must be mounted at average breathing hieght.

I could see that gases would mix quickly if there specif gravity was relativley close, like nitrogen/oxygen, which why were alive, because our atmosphere contains 78% nitrogen and 21% oxygen, they wont seperate because the sg is so close to each other, oxygen is actually slightly heavier than nitrogen which is why as altitude increases and pressure changes oxygen starts to thin out. but if the specific gravity of the gas was really high or low it would rise or fall, like helium floats with an sg of .138 and co2/propane would drop sg 1.5

Im a gas fitter/refrig mechanic by trade and co2 will seperate and sit in low undistirbed areas and is responsible for deaths every year due to suffocation and is the reason when im working in underground mechanical rooms i must use a oxygen detector attached to my belt, the gas burners use the oxygen in the rooms and release co2 and co, the co2 will settle in the mechanical rooms pushing the oxygen up through the vents. The co is the bad one and will kill you quick, co2 is the other silent killer and you can suffocate quickly.

That being said with the following sg readings:
Argon:1.38
Nitrogen:.996
Co2:1.51

Id say the co2 is probly your safest bet for protecting your wine as left undistirbed will seperate and form a cover as well as the argon. I use nitrogen only because i have free access to it as i use it to pressure test refrigeration systems at work so its free for me but probly the last choice out of those 3 gases i would choose to protect my wine.

 

[dcbrown73]

This is true. Gases will blanket (layer) "with time" *IF* it is left undisturbed. Heavier gasses will sink and separate beneath lighter gasses. Liquids have this same effect, but they must be left undisturbed for this effect to happen.

People ask why CO2 in the atmosphere doesn't sink to the ground, but that's easy to explain. Wind currents prevent it. The gasses have to be left undisturbed for gravity to cause this layering effect to occur.

That said, if oxygen is in the carboy, it will have access to the wine early on and when you disturb the carboy.

 

[GaDawg]

I use an all-in-one Wine Pump Headspace Eliminator
https://www.allinonewinepump.com/product/headspace-eliminator/

 

[Smok1]

I use an all-in-one Wine Pump Headspace Eliminator
https://www.allinonewinepump.com/product/headspace-eliminator/

Even though a vacuum is a great way to reduce oxygen there is still oxygen in a vacuum, there is no such thing as a perfect vacuum and even with a commercial vac pump capable of pulling a true 29.96” hg there will still be a presence of oxygen.

 

[Ajmassa]

Even though a vacuum is a great way to reduce oxygen there is still oxygen in a vacuum, there is no such thing as a perfect vacuum and even with a commercial vac pump capable of pulling a true 29.96” hg there will still be a presence of oxygen.

Yes, this is true, BUT....

A vacuumed seal is "Not just good.... Good enough!"

 

[Smok1]

Yes, this is true, BUT....

A vacuumed seal is "Not just good.... Good enough!"

Yep i agree it makes a great seal.

 

[Johnd]

Remember folks, the goal here is not the complete elimination of all exposure to oxygen, but instead, the prevention of over-exposure to oxygen. Bungs leak, corks leak, barrels leak, but it's all ok, as long as it's not excessive. Store 3 gallons of your finished wine in a 6 gallon carboy for several months, you're on your own.

Your wines cannot mature without controlled exposure to oxygen, yes they will age (physically get older), but they won't develop in quite the way that controlled exposure to oxygen ages them over time, as with barrels and corks.

To control the over-exposure to oxygen, the techniques described above work: controlling the amount of headspace by topping up, creating an environment in which a partial vacuum (not perfect) exists, replacing as much of the non liquid area with inert gases / less oxygen. Oxidation is a process that takes time, thank goodness, or we'd all ruin our wines while pressing them off of the grapes.

In the end, find one that works for you, your habits, your equipment, and your wine production techniques. Could be a combo of some or all of the above.

My personal preference, because I've put myself in the position to have numerous vessels of different volumes, is to simply store my wine in appropriately sized vessels with very little headspace, ranging in size from 12 gallon demi's, down to 375 ml bottles.

 

[Smok1]

Yes agreed some oxygen exposure is good for wine development which i dont know if this is the right thread for it but i just purchased twin corks for my reds, there real cork on the top and bottom and alggomated in the middle, does anyone use these? Real corks here in canada are very expensive but i have read are the best for micro oxidization for nice red wines but i couldnt bring myself to pay the price for it, i thought maybe these twin corks, or 1+1 corks may be the second best option.

 

[NorCal]

Yes agreed some oxygen exposure is good for wine development which i dont know if this is the right thread for it but i just purchased twin corks for my reds, there real cork on the top and bottom and alggomated in the middle, does anyone use these? Real corks here in canada are very expensive but i have read are the best for micro oxidization for nice red wines but i couldnt bring myself to pay the price for it, i thought maybe these twin corks, or 1+1 corks may be the second best option.

This what I use, but I use the fatties (#9) cork.

 

[NorCal]

Where did you get the one way valve?

Private Message sent

 

[sour_grapes]

There must be an exception to the blanketing effect because i install commercial CO/propane detectors at work and gas code calls for the propane detector to be placed 1” from the floor and the CO to be mounted at 5”, so vapor propane has an sg of 1.52 and it settles on the floor of parkades, which is why its a bigger hazard than natural gas which has an sg lower than air and dissapates rather than settles. Co detectors are placed at 5” because its sg is so close to air that code states it must be mounted at average breathing hieght.

Note that I said the gases mix on the time scale of tens of seconds. The cases you cite are those for which there is a source of one of the gases. Yes, a denser gas will initially fall, and a less dense gas will rise. However, the molecules will eventually mix in. This will take a minute or two. But you are not storing the wine for a few minutes, you are storing it for months.