Headspace after primary fermentation.

[sour_grapes]

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.

 

[balatonwine]

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.

 

[GaDawg]

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

 

[balatonwine]

This is true. Gases will blanket (layer) "with time" *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.

 

[Ajmassa]

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.

 

[sour_grapes]

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.

 

[Ajmassa]

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.

 

[RonObvious]

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?

 

[sour_grapes]

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

 

[Smok1]

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

 

[Ajmassa]

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.

 

[RonObvious]

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?

 

[Smok1]

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

 

[RonObvious]

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?

 

[AZMDTed]

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

 

[Ajmassa]

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.

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. .

 

[ricchezza]

“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.

 

[opus345]

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