Vacuvin degassing question, aging under vacuum?

[LeChat]

Hi there,

I currently have several kit wines aging in carboys. While I wait for to purchase a vacuum pump, I am using a hand held wine saver (vacuvin) to create a bit of vacuum to remove CO2 from my wine. I pull vacuum for about a week or until bubbles are no longer coming out of the wine so freely.

I was wondering if there was any risk of oxidating the wine if I do not top off while doing so. For a bit of context, we are talking about maybe a bottle missing to top off the carboy.

From my vantage point, the "air" at the top of the carboy is mostly vacuum and CO2 pulled from the wine, spoilage should not be a concern for moderately short degassing periods (i.e., maybe a week or two tops). What do you think?

Thanks,

 

[Wild Duk]

That's how I see it... The headspace should be all CO2. I use a brake bleeder, and after a few, it will actually hold a vacume of around 5-10".
So I believe that if its left to sit overnight or a week even, that there is no risk of oxidation as there is no air in the headspace....

 

[TonyP]

I'm not entirely clear on your situation, but it does appear to me you may have an oxidation issue. While I believe the VacuVin is a good product, I don't believe the vacuum will hold for two weeks without letting in some air. I just doubt the product was designed to last that long. If you keep the VacuVin cap on between pumpings and the cap pops when you remove it - indicating the vacuum held - you should be fine.

BTW, I would be more concerned if you used a BetterBottle carboy instead of glass.

 

[LeChat]

Thanks for the replies.

I am actually pumping like a madman each time I go by the carboy. But it is a good point that air (and thus oxigen) will sneakily try to get in and spoil my party because of the negative partial pressure of the air in the carboy.

@Wild can you comment on how long you need to pump for it to degas properly?

 

[saramc]

The bigger issue with oxidization risk in this situation is lack of proper SO2 levels.

 

[ibglowin]

I think within minutes you will have enough air creep back in that you will be at normal atmospheric pressure. What makes you think a $10 device will hold a vacuum seal for any longer than you are pumping on it? The Vacuvin will degas your wine but it will in no way protect it from oxidation. Top it up ASAP!

 

[robie]

Even if you could keep it under vacuum for extended periods of time, it could rob your wine of some of the aroma creating substances.

 

[Wild Duk]

LeChat, I'm not really sure how long. depends on how long I go into the room and pump it up....I just degassed a Pinot Grigio i'm making in about 5 days.....thats pumping it up about 10 times a day...
That said, the device I use, a brake bleeder, will hold pressure at least overnight.....After you get some of the CO2 out of solution, you have to pump it to a higher pressure to get more out....SO after about the first day, I will pump it up to about 18" and let it sit and degass.....In the AM I will go in and the guage will be on about 5", so there is a vacume in there, hence no O2 for oxidation......
I do this technique until it holds 15" for an hour or so....Then it seems totaly degassed.....

Not sure about extracting aromas...I may, but 5" hg pressure isn't really a whole lot....Who knows

 

[LeChat]

@IBG

In my experience, vacuum is still present after more than a week. If the rubber stopper can hold vacuum that long, it can likely hold it indefinitely (assuming no atmospheric pressure changes). I agree that the wine is not protected from oxidation meanwhile.

Rest assured, I don't intend to leave the wine like this a long time, only until it is sufficiently degassed (1-2 weeks).

@Robie

Really!? Can you expand on what happens to the aromatic coumpounds?

@Wild

Good to know that a brake bleeder does the job in a pinch. I was debating purchasing this instead of saving for a vacuum pump.

 

[Wild Duk]

Not to change your mind, but if you intend on keeping this hobby and making lots of wine, I'd save for a pump. I am.... The brake bleeder works but still not fast....
Every time I'm degassing a wine I do a quick eBay search for pumps....

 

[Stressbaby]

I have used the Vacuvin many times and I agree with LeChat. The pressure is still sub atmospheric even after several days. It is no doubt higher than just after pumping but it is very difficult to know if this is leakage of air in or if it is release of CO2 from the wine.

 

[GreginND]

Really!? Can you expand on what happens to the aromatic coumpounds?

If it is left under vacuum for extended periods of time you will lose alcohol and other volatile aromatic compounds. They will evaporate into the vacuum space.

 

[ibglowin]

I hate to bust your bubble here but anyone, repeat, anyone who has ever used a Vacuvin for its actual intended purpose knows full well that the leftover wine in an opened bottle that has been "evacuated" with a Vacuvin is basically shot as in oxidized and taste like crap in about 24-48 hours at BEST. Even though it still has that nice "whisp" of air being released when you pinch it open.... There is PLENTY of O2 still in that bottle.

You are kidding yourself if you think for one minute that a Vacuvin will protect your wine in ANY real fashion at ALL. You would be better off with a can of Private Reserve and flooding the headspace with inert gas even that would only protect you for a week or so at BEST.

 

[LeChat]

Mike, I don't really think that you can compare an almost empty wine bottle vs a recently sulfited wine in a carboy that is 97% full.

The ratio of oxygen to wine is diametrically opposed in those two situations and I don't think that you can just extrapolate.

Also, nobody here is saying that they are using a vacucin to protect their wine against oxygen in a carboy. I am not suggesting that anybody does so either. I am questioning on when it would actually become nefarious to the wine.

however, given what we have discussed in this thread, I would posit that wine under vacuum in a carboy would actually fare pretty well even in 6 months time. I would even be willing to wager on this. If you think about it, each time you open a carboy for any reasons, you are introducing a significant amount of oxygen in it which would be even worse.

 

[robie]

@Robie
Really!? Can you expand on what happens to the aromatic coumpounds?

Wish I could. It is like a lot of other things I have learned - I know I read it but I can't necessarily give you the author, article, and date.

A couple years ago the subject came up about whether or not to leave an air lock on a carboy (regular 6-gallon carboy) after 6 months to a year of bulk aging. I believe it was George at FVW who wrote about it affecting the wines aroma over a prolonged period of time. It is safe to say that a wine left under a continuous vacuum for a prolonged period of time could excellerate that same effect.

Here's another place where I believe I got it. I apologize to Daniel if I am wrong about this... There was a study done comparing vacuum degassing .vs. stirring. It was shown on this forum within the last year or so. If I remember right, it was done by Daniel Pambianchi, a very well know author and wine expert. In it I believe he spoke about vacuuming affecting the aroma and the aroma creating compounds in the wine.

 

[ibglowin]

Are you kidding! Thats exactly what your trying to do by saying because there is more wine to volume of headspace that it won't be affected as much, i.e. your extrapolating.......

It doesn't matter if you have a half bottle or a bottle with one glass gone which is ~ the same amount of headspace your talking about. The wine will still taste like shat after 48 hours max.

So extrapolate that all you want. Its your wine, but it is in no way protected in any fashion by a Vacuvin.

The ratio of oxygen to wine is diametrically opposed in those two situations and I don't think that you can just extrapolate.

 

[LeChat]

@Mike- Actually, that would be interpolating, but I digress. Thanks for your opinion. As I already stated, we are not looking at protecting wine by using a Vacuvin. I am more interested in quantifying the rate of decay. I want to understand what happens between the moment the cap is put on and vacuum is applied and the moment the wine becomes oxidated and quantify the interval. We already know that the end result is wine that tastes like Cambronne's effluent.

@Robie Thank's for the lead. I will try to dig up the article. I have a feeling that the phenomenon would be exacerbated by strong vacuum. It would be interesting to find out if altitude aging affects wine in a similar fashion given that the atmospheric pressure is bound to be similarly lowered.

 

[seth8530]

If you want to make an experiment of it you could take glasses of different surface areas but with equal volumes and figure out how long it takes for them to oxidize based on area.

Then you could preform another experiment where you use glasses with equal surface areas but different volumes and see how long it takes for them to oxidize.

I think it would be an interesting experiment.. No?

 

[Wild Duk]

Well the main difference is that the bottle of wine is not degassing CO2 as your Carboy would. Being that CO2 is heavier than air, I do believe that it would make a blanket over your wine...
That said, I feel the same way and would not leave it itself for a week at a time cause who really knows what is going on in there...I'm sure those $10 vacu vins don't seal perfectly...
But I still believe that with the brake bleeder set up, you could leave it as it pulls out CO2 then leaves a vacume when the pressure to pull it out is higher than the vacume in the headspace.
I still don't leave it for weeks at a time, but overnight, I think your fine...

 

[Stressbaby]

The other way that preservation/oxidation is different when using a Vacuvin for degassing, as compared to a Vacuvin for preserving an open bottle of wine, is that the content of the gas in the headspace is different.

With an open bottle, the volume is plain air, just at subatmospheric pressure. I suppose that the rationale for using the Vacuvin in that setting is that the total available oxygen is lower when using the device...however, whatever the volume of air, it is still 20% oxygen. If it leaks, it just allows more air, again, 20% oxygen. The composition of the gasses in the headspace doesn't really change.

With degassing, the headspace starts as air but is quickly replaced with straight CO2. With a reasonably small headspace, it is COMPLETELY replaced with CO2, and at that moment the rate of decay should be zero. The volume of headspace shouldn't matter at that point if degassing is occuring. If the device leaks at that point, it may allow air in. This air is 20% oxygen, and so the CO2 in the headspace is diluted with air and oxygen is available to spoil the wine. It seems to me as if the rate of decay is proportional to the frequency at which you replace the mixed gases in the headspace with new CO2...that is to say, the frequency at which you pump the thing. If I pump the thing 5 times a day and replace the headspace with straight CO2 each time I pump, I'm thinking the oxidation risk is pretty low, even if it leaks...