Co2

[Vlabruz]

I couldn't really find the answer. If you fill head space with co2 with it carbonate the wine or does it need the pressure behind it?
I'm assuming id you were to keg wine you need to use nitrogen?
Its two separate questions incase I confuse anyone. First pertaining to bulk aging in glass carboys.

 

[winemaker81]

To carbonate, it needs enough pressure to force some CO2 into suspension. I have no experience with kegging.

 

[Vlabruz]

To carbonate, it needs enough pressure to force some CO2 into suspension. I have no experience with kegging.

Thats what I figured. So, if co2 settles how will o2 get below it to oxidize your wine? And where does the co2 go when your wine is degassing if its heavier than o2 won't it just stay on top of the wine?

 

[sour_grapes]

Thats what I figured. So, if co2 settles how will o2 get below it to oxidize your wine? And where does the co2 go when your wine is degassing if its heavier than o2 won't it just stay on top of the wine?

Gases do not "settle." They mix thoroughly and completely. All O2 in the headspace has "access" to your wine.

 

[Jim Welch]

I couldn't really find the answer. If you fill head space with co2 with it carbonate the wine or does it need the pressure behind it?
I'm assuming id you were to keg wine you need to use nitrogen?
Its two separate questions incase I confuse anyone. First pertaining to bulk aging in glass carboys.

It WILL force carbonate your wine if there is any pressure behind it. There are charts for beer kegging which will show you how many “volumes “ will go in at certain CO2pressure/temperature combinations. I’ll try to find a chart and post it here. Iirc, I posted one in another thread about this subject a while ago.

Using nitrogen will result in nitrogenated wine, but it comes out of solution quicker and does not create carbonic acid like CO2 will.

I use argon to seal and dispense winein/from my corny kegs. As a matter of fact I just finished about an hour ago kegging 4 batches of wine into corny kegs and used argon. It will not, or perhaps a minuscule amount, go into solution. Most if not all bars/restaurants that have wine on tap use argon.

 

[Jim Welch]

Just reread your post, I guess I’ve got kegging wine on my mind, Clearing the lines between batches and drinking it didn’t help my thinking either!

I see you’re talking about filling the headspace in a Carboy or something with no pressure beyond atmospheric pressure. No carbonation at atmospheric pressure or at least nothing noticeable. Wine will degass the natural fermentation caused carbonation anyway so you’re fine.

Filling excess headspace with CO2 is a temporary fix though, O2 will still get in in time. Not sure if that’s an issue but thought I’d mention it.

 

[winemaker81]

Gases do not "settle." They mix thoroughly and completely. All O2 in the headspace has "access" to your wine.

There is a common belief that a gas can be pumped into a carboy and if heavier than air, it will form a distinct layer, as is done with some drinks. IIRC Paul (sour_grapes) explained in detail a while back that this belief is incorrect. My understanding is the result of adding CO2 is more like pouring red wine into a glass of water -- it disperses quickly, and while the result is not homogeneous, it's well mixed up.

If enough CO2 is pumped in, it will displace the air as what's at the top of the carboy will get pushed out. However, how much is enough? It's all invisible gases so "enough" is a hope, not strong enough to be a guess.

I suppose that enough CO2 to carbonate a wine is enough to displace the air, but have no evidence of that.

 

[Rice_Guy]

The quantity of CO2 which will dissolve is linearly related to the partial pressure of that specific gas in the head space above the liquid.
This means that if the headspace is 1% CO2 the soluble gas will be 1% of what would be soluble if there were 100% CO2 in the headspace.
This means that if the pressure of a 1% CO2 atmosphere were increased by 100 times the soluble gas would increase by 100%.

The technical answer is that the CO2 is in equilibrium with the wine.

If I went to Henry’s law the solubility = K(constant) X partial pressure

Partial pressure = atmospheres X percentage

* Therefore on a new wine which is degassing there is back pressure on the air lock and the percent of CO2 could be close to 100 percent and we could guess that the the wine is saturated with 1 atmosphere of CO2.
* the magic of any vacuum pump is that it will decrease the atmospheres of pressure and we push the equilibrium lower (linear with the % vacuum, per formula above)
* The magic of running through a vacuum transfer is that the droplet size is reduced (significantly below 5 gallon) therefore we can assume that we are in equilibrium as stated by the gas law, now and at every instant time. The wine will seek the same equilibrium with atmospheric pressure but get to equilibrium faster.
* Steve I don’t like calc enough (dynamic system modeling) that I lay awake at night wondering but the engineering profs train us to know what the dynamic processes are and then consider risk/ benefit.
For talking with vacuum customers (or a boss with a marketing degree) the key thing to get say is that “the effect is linear with the pressures”, , , , so talking in percent of atmosphere is easy to understand.

 

[Vlabruz]

There is a common belief that a gas can be pumped into a carboy and if heavier than air, it will form a distinct layer, as is done with some drinks. IIRC Paul (sour_grapes) explained in detail a while back that this belief is incorrect. My understanding is the result of adding CO2 is more like pouring red wine into a glass of water -- it disperses quickly, and while the result is not homogeneous, it's well mixed up.

If enough CO2 is pumped in, it will displace the air as what's at the top of the carboy will get pushed out. However, how much is enough? It's all invisible gases so "enough" is a hope, not strong enough to be a guess.

I suppose that enough CO2 to carbonate a wine is enough to displace the air, but have no evidence of that.

This is what I'm curious about. How much is enough and if you knew would that be good to prevent oxidation.

 

[winemaker81]

This is what I'm curious about. How much is enough and if you knew would that be good to prevent oxidation.

I have absolutely no clue. I top with wine and I am 100% positive of my solution.

This is a matter of risk tolerance. I don't trust what I cannot verify. Other folks do ...

 

[Rice_Guy]

the potential for oxidation is related to the number of oxygen molecules! If you are looking for a ratio of CO2 dissolved, it won’t work. Oxygen also follows the gas law. One deduction you can make from this is that if oxygen will react and stop being elemental oxygen this void will pull any residual molecules of oxygen out of the head space, ,,, untill there is none left!

CO2 can be used to flush/ lower the percentage oxygen/ reduce the number of molecules you start with, but eventually all available oxygen will be consumed.

How much is enough and if you knew would that be good to prevent oxidation.

the traditional comment is reduce the head space as much as possible/ number of molecules, ,,, ie do the best we can.

 

[ratflinger]

I also use argon for kegging & am pleased with the outcome.

 

[sour_grapes]

The quantity of CO2 which will dissolve is linearly related to the partial pressure of that specific gas in the head space above the liquid.
This means that if the headspace is 1% CO2 the soluble gas will be 1% of what would be soluble if there were 100% CO2 in the headspace.
This means that if the pressure of a 1% CO2 atmosphere were increased by 100 times the soluble gas would increase by 100%.

Oh, Henry !

 

[HillPeople]

I use CO2 to temporarily fill small headspaces.
Put the CO2 in at a slow whisper and hold a lit match over the mouth.
When it goes out there is enough CO2 in the headspace.
Argon is better.
Topping up with wine even better.

 

[winemaker81]

Put the CO2 in at a slow whisper and hold a lit match over the mouth.
When it goes out there is enough CO2 in the headspace.

Cool! This solves my problem, "how to determine the CO2 level?" This should work with any inert gas.

 

[stickman]

Unfortunately normal combustion doesn't continue below 16% oxygen, so the flame method of detection isn't good enough to verify the vessel is completely CO2 filled.

 

[sluff]

I also have argon, but when I use it I have no idea when/if the headspace has enough argon to do the job. The lit match method apparently doesn’t work - and I’m always afraid of dropping ash or burned match fragments into the wine. Does anyone have any good ideas on knowing when enough is enough? Thanks!

 

[Jim Welch]

I also have argon, but when I use it I have no idea when/if the headspace has enough argon to do the job. The lit match method apparently doesn’t work - and I’m always afraid of dropping ash or burned match fragments into the wine. Does anyone have any good ideas on knowing when enough is enough? Thanks!

I’ve never tried this but I’ll put it out there. Immerse the end of the gas tube into the wine and you might get a foam. If you do, let the foam rise nearly to the opening , withdraw the tube and insert the stopper. Might need a high flow rate and submerge the end in fairly deep.

 

[sjjan]

Isn’t argon not heavier than air? As a Noble gas it seems to be 1.38 times heavier than air. So if most of the headspace is filled with argon, it will sink and sit right on top of the wine to protect it from any air left in the carboy. At least, this is my theory, but might not be valid

 

[cmason1957]

Isn’t argon not heavier than air? As a Noble gas it seems to be 1.38 times heavier than air. So if most of the headspace is filled with argon, it will sink and sit right on top of the wine to protect it from any air left in the carboy. At least, this is my theory, but might not be valid

Your theory is not valid, it will mix. Think about our atmosphere CO2 is heavier than Oxygen, if what you theorize were to happen the bottom layer of our atmosphere would be CO2. But it is the mix we breath.