# Headspace after primary fermentation.



## ricchezza (Oct 13, 2017)

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).


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## jgmann67 (Oct 13, 2017)

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.


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## AZMDTed (Oct 13, 2017)

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.


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## Smok1 (Oct 13, 2017)

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.


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## NorCal (Oct 13, 2017)

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.


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## Smok1 (Oct 13, 2017)

NorCal said:


> 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?


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## bkisel (Oct 13, 2017)

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.


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## Ajmassa (Oct 13, 2017)

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/


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## sour_grapes (Oct 13, 2017)

Smok1 said:


> 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.


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## Smok1 (Oct 13, 2017)

sour_grapes said:


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



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.


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## dcbrown73 (Oct 13, 2017)

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.


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## GaDawg (Oct 13, 2017)

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


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## Smok1 (Oct 13, 2017)

GaDawg said:


> 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.


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## Ajmassa (Oct 13, 2017)

Smok1 said:


> 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!"


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## Smok1 (Oct 13, 2017)

Ajmassa5983 said:


> Yes, this is true, BUT....
> 
> A vacuumed seal is "Not just good.... Good enough!"



Yep i agree it makes a great seal.


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## Johnd (Oct 13, 2017)

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.


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## Smok1 (Oct 13, 2017)

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.


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## NorCal (Oct 13, 2017)

Smok1 said:


> 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.


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## NorCal (Oct 13, 2017)

Smok1 said:


> Where did you get the one way valve?


Private Message sent


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## sour_grapes (Oct 13, 2017)

Smok1 said:


> 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.


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## sour_grapes (Oct 13, 2017)

dcbrown73 said:


> 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.



No, it is not just wind currents. It is the kinetic energy of the motion of the gas molecules. The kinetic energy completely dominates the potential energy of gravity. Molecules bounce around at about 1150 mph. If you took a molecule going that speed, and you directed it upwards in a vacuum (i.e., it didn't hit another molecule), it would go 19 miles upwards before gravity would slow it to zero. These are not objects that are going to "settle out" due to gravity.

It is true that there is a _slight_ enhancement at lower atmospheres; very slight. To cite an example, Ar is about 0.5% of the atmosphere at sea level. At 1000 m (3300 ft), it would be about 0.48%. Clearly, the difference between the top and bottom of your carboy will be negligible.

So, in particular, the gas will NOT blanket at room temperature even if left undisturbed. The temperature _*IS*_ the disturbance that keeps them mixed.


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## balatonwine (Oct 14, 2017)

Smok1 said:


> There must be an exception to the blanketing effect



When it comes to the limited area of the container above the wine, not really. Then random molecular movement factors are more important. And any O2 in that space will eventually contact the wine. Rather, when applying gas into the airspace one tries to add so much that it displaces most of the O2. CO2 is often used, because it is cheaper. But CO2 soluble in the wine can affect the wine. Which is why a nitrogen is preferred, but it is more expensive for small wineries which do not have the equipment to extract nitrogen from the air.


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## GaDawg (Oct 14, 2017)

Smok1 said:


> 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.



While what you say is true, the headspace eliminator works for me and that is all I care about. I personally would rather have great wine as opposed to a perfect process! Don't let the perfect be the enemy of the good


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## balatonwine (Oct 14, 2017)

dcbrown73 said:


> This is true. Gases will blanket (layer) &quot;with time&quot; **IF* it is left undisturbed*.


 At room temperatures all air molecules have enough kinetic energy to intermingle over time despite their relative densities and will not differentiate. What you suggest only occurs at temps far below normal temps we experience on a daily basis.


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## Ajmassa (Oct 14, 2017)

I use the headspace eliminators also. But I was looking into a setup for flushing inert gas that was something quick and easy. I basically have zero existing knowledge on the topic though. 
I assumed there was some sort of gun with a hose attached that utilizes the smaller co2 cartridges. And a case of cartridges and the gun would make for easy purging. 
My searches were overwhelming, not knowing what exactly id need. But I also found these cans. They seem like they would be ideal. But again, no knowledge on what 'ideal' actually is in this circumstance.


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## sour_grapes (Oct 14, 2017)

Ajmassa5983 said:


> I use the headspace eliminators also. But I was looking into a setup for flushing inert gas that was something quick and easy. I basically have zero existing knowledge on the topic though.
> I assumed there was some sort of gun with a hose attached that utilizes the smaller co2 cartridges. And a case of cartridges and the gun would make for easy purging.



Lest you all get a different impression, I am not at all opposed to using an inert gas or CO2 to displace O2 from the headspace. Let's say you have 2 liters of headspace. If you can go in and carefully purge/displace the air, you can reduce that 2 L of air to the equivalent of, say, 0.1 L. That is a big improvement.

The only point that I have been making is that (in my example) the equivalent 0.1 L of air has unfettered access to your wine (after a few minutes go by). But that may be a smaller volume than the volume of headspace in a well-topped off carboy. It may be a smaller amount of O2 left than if you used a vacuum pump.

For this application, you want to introduce the inert gas near the surface of the wine, and you want to do it without turbulent mixing. This means introducing the inert gas smoothly, at low flow rates. As I keep saying, you have tens of seconds to several minutes before molecular diffusion becomes important, so you can flush nearly all the air out with a slow, steady stream.

I do not have experience with Private Preserve and the like, but I worry that the stream might come out too fast, and induce turbulence.


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## Ajmassa (Oct 14, 2017)

sour_grapes said:


> For this application, you want to introduce the inert gas near the surface of the wine, and you want to do it without turbulent mixing. This means introducing the inert gas smoothly, at low flow rates. As I keep saying, you have tens of seconds to several minutes before molecular diffusion becomes important, so you can flush nearly all the air out with a slow, steady stream.
> 
> 
> 
> I do not have experience with Private Preserve and the like, but I worry that the stream might come out too fast, and induce turbulence.




I actually just read about that. And was explained using the comparison of water flowing freely from a spigot opposed to covering half with your thumb blasting the water into a bucket. 
http://morewinemaking.com/public/pdf/inertgas.pdf
I was just assuming those cans were trigger sensitive and not just full blast. I don't know. Just spitballing. And trying to see if there were any any simple easy accessible and relatively inexpensive ways to go about this. 
I think The ability to give a purge of gas throughout the process would be a nice addition to a setup.


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## RonObvious (Oct 19, 2017)

Regarding the smaller cans of inert gas like Ajmassa5983 mentions, has anyone done the math to figure out how much volume is in them? The Private Reserve brand says it contains 0.29 oz (8.2g), but what does this equate to in terms of volume (at average room temp and pressure)?

Funny thing is, I was an engineer in a former life and could probably figure it out myself, but I'm pretty rusty so I'm hoping someone might already have a rule of thumb already. I remember PV=NRT and that's about it. 

I have used these small canisters for years to preserve open bottles that I plan to drink later, and I can confirm that they work great for this purpose. So I imagine they'd work well for wine making too. 

I'm really just trying to figure out whether it's more economical to buy a cylinder from a gas supplier. I visited my local AirGas today and long story short, it can get pretty expensive. If I can figure out roughly how much inert gas is in these cheap canisters, I might be happier ordering a few per year, rather than investing in a cylinder. 

Of course, it can be tricky filling a carboy with these because it's hard to regulate the flow. It comes out really fast through a tiny straw and you never know exactly when you have evacuated all the oxygen. But I imagine you'd have the same problem with a big cylinder too?


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## sour_grapes (Oct 19, 2017)

(8.2 g)/(40 g/mole)*(22.4 Liter/mole) = 4.6 liters.


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## Smok1 (Oct 19, 2017)

Once you pay the deposit on the cylinder from the gas supplier the gas is cheap, i think the tank deposit was $125 full, and each refill is $40 for nitrogen, and a tank of gas will last you a long time


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## Ajmassa (Oct 19, 2017)

Thanks for sharing your experiences with those Ron. They sound like they'd get the job done. For so cheap it's worth a try. 

OR I could head back to the future and pick up a few Variable Capacity Carboys.


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## RonObvious (Oct 19, 2017)

Thanks Paul - 4.6 liters it is! So a little over a gallon. Which I guess means that if you're just worried about a single carboy or maybe two that are just a little under the neck, then maybe these cheap canisters might be a legitimate option. 

Smok1, sounds like you use nitrogen? I assume it works well for you?


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## Smok1 (Oct 19, 2017)

RonObvious said:


> Thanks Paul - 4.6 liters it is! So a little over a gallon. Which I guess means that if you're just worried about a single carboy or maybe two that are just a little under the neck, then maybe these cheap canisters might be a legitimate option.
> 
> Smok1, sounds like you use nitrogen? I assume it works well for you?




Seems too. Ive been trying to collect a few different size carboys, i have 1,2,3,4,5,6,6.5 gallon carboys so i try to keep them as topped up as possible with what i have on hand, if i cant get it within a couple inches from the top i run nitrogen into the carboy using the extra 2 hole bung i got with my allinone wine pump, i figure if i let the nitrogen flow in nice and slow i to the one hole it should push the majority of the oxygen out after purging for a min or so. Nothings perfect but works for me so far


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## RonObvious (Oct 20, 2017)

You know, I never thought about using a 2-hole bung - great idea!

Anybody ever used marbles to take up the extra space? I think marbles are made of glass, right? So they shouldn't impart any flavor?


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## AZMDTed (Oct 20, 2017)

Well, I think we've done a good job scaring away the original poster.....


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## Ajmassa (Oct 20, 2017)

AZMDTed said:


> Well, I think we've done a good job scaring away the original poster.....





I don't see why. I think he started a good convo just as he intended. 



ricchezza said:


> 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. .


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## ricchezza (Oct 22, 2017)

“I think he started a good convo just as he intended.” - you are correct.

I did specifically mention “secondary” in my original post; but, was more concerned about the long term aging vessel headspace. The thread evolved into a more interesting conversation about the mixing and densities of various gasses.

As mentioned prior, this is my first wine, but I’ve been doing beer for many years. For what it’s worth, despite many beginner tutorials, I do not use a secondary fermentor unless I’m doing long term aging before bottling/kegging.

Tutorials are nice; I wanted to ask the folks on here with the real, and varied, “hands-on experiences” for insight.

Thank you everyone.


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## opus345 (Oct 22, 2017)

RonObvious said:


> You know, I never thought about using a 2-hole bung - great idea!
> 
> Anybody ever used marbles to take up the extra space? I think marbles are made of glass, right? So they shouldn't impart any flavor?



Never used marbles, too worried about them cracking/breaking themselves or the carboy, but some have used with success.

http://www.winemakingtalk.com/forum/showthread.php?t=55860&highlight=marbles

http://www.winemakingtalk.com/forum/showthread.php?t=57401&highlight=marbles&page=2


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