Vacuum Degassing - calling all science nerds

[RottenGrapeJuice]

So I am familiar with vacuum transferring wine, which will degas in the process of racking, so I came up with the brilliant idea to just connect the vacuum pump directly to the carboy to pull a vacuum and let the CO2 escape. What I found was that under vacuum, many many large bubbles started rising to the surface pretty vigorously, and I thought to myself “wow this was a great idea, I don’t have to use a wine whip for an hour”. Then it dawned on me, this is not CO2 escaping, I’m literally boiling the water and alcohol in the wine due to the extremely low pressure. So I ultimately ended up grumpy on the couch with my wine whip for the next hour. Am I right? Has anyone tried this?

 

[Johnd]

So I am familiar with vacuum transferring wine, which will degas in the process of racking, so I came up with the brilliant idea to just connect the vacuum pump directly to the carboy to pull a vacuum and let the CO2 escape. What I found was that under vacuum, many many large bubbles started rising to the surface pretty vigorously, and I thought to myself “wow this was a great idea, I don’t have to use a wine whip for an hour”. Then it dawned on me, this is not CO2 escaping, I’m literally boiling the water and alcohol in the wine due to the extremely low pressure. So I ultimately ended up grumpy on the couch with my wine whip for the next hour. Am I right? Has anyone tried this?

Been doing it for years, works like a charm. When you get the big bubbles, you’re done. You haven’t boiled the alcohol out of your wine, get off the couch and put on your happy face, your wine is fine. You’d have to run the vacuum for days to make any appreciable difference. I’ll post a good article here for you as soon as I can find it.

OK, so the article is posted in this thread: Degassing in a carboy....
Its a really good read, all the science nerds were on board, enjoy some WMT history!!!

 

[BernardSmith]

Totally, agree wit Johnd. You are nowhere near "boiling the alcohol" . The vacuum is simply forcing the CO2 to escape. BUT your post suggests a REAL liability. You say you connected the vacuum pump DIRECTLY to your carboy? The danger is that you MIGHT pull liquid from the carboy INTO the pump and depending on the kind of pump you are using that could be disastrous. What you want to do is pull a vacuum through and empty container (could be a smaller carboy that will trap any liquid that you may accidentally pull along with the CO2. Not an agent for Vacuumpump Man on this forum but he used to sell double drilled bungs for precisely this purpose

 

[RottenGrapeJuice]

Totally, agree wit Johnd. You are nowhere near "boiling the alcohol" . The vacuum is simply forcing the CO2 to escape. BUT your post suggests a REAL liability. You say you connected the vacuum pump DIRECTLY to your carboy? The danger is that you MIGHT pull liquid from the carboy INTO the pump and depending on the kind of pump you are using that could be disastrous. What you want to do is pull a vacuum through and empty container (could be a smaller carboy that will trap any liquid that you may accidentally pull along with the CO2. Not an agent for Vacuumpump Man on this forum but he used to sell double drilled bungs for precisely this purpose

Yea I understand that risk, and was planning on shutting down the pump if the foam got that high (carboy wasn’t topped off). I have the orange bungs that I use to vacuum transfer. Anyway, when you lower the pressure enough, water boils at room temperature, so I don’t know that we can conclude that the water is NOT boiling. The vacuum pump I have says it’s rated for 5 pascals, which is well below the vapor pressure of water, which would lead to boiling regardless of the fact we’re at room temperature. Having said that, I also can’t conclude that I’m not just seeing large bubbles of CO2 coming up.

 

[winemaker81]

So I ultimately ended up grumpy on the couch with my wine whip for the next hour.

Were you whipping the wine for an hour? If so, that's WAY overdoing it.

Degassing the wine is not a short term thing. Kit instructions typically state to stir the wine (using a drill mounted stirring rod) for 2 to 3 minutes, changing direction every 30 seconds. While this expels a lot of CO2, it does not get it all. It jumpstarts the process and the wine continues to degas over the next few days or weeks.

In recent years I degas all wines, as with the CO2 reduced, the gross lees drops faster without CO2 to hold it in suspension. I don't use a watch during degassing; I count. In reality I'm probably only stirring for 20 seconds in each direction, so I'm doing less than the 2 to 3 minutes. If I planned to bottle 4 weeks after starting, this may not be enough. But my current habit is to not bottle before 6 months (some reds a year) so it works fine for my needs.

 

[BernardSmith]

Yea I understand that risk, and was planning on shutting down the pump if the foam got that high (carboy wasn’t topped off). I have the orange bungs that I use to vacuum transfer. Anyway, when you lower the pressure enough, water boils at room temperature, so I don’t know that we can conclude that the water is NOT boiling. The vacuum pump I have says it’s rated for 5 pascals, which is well below the vapor pressure of water, which would lead to boiling regardless of the fact we’re at room temperature. Having said that, I also can’t conclude that I’m not just seeing large bubbles of CO2 coming up.

Alcohol has a lower SG than water. If you suspect that you are boiling off the alcohol. Measure the SG. It will be HIGHER after removing the alcohol than with the alcohol (that is one method of measuring the alcohol content of a wine about which you have no idea of the starting gravity: you boil off ALL the alcohol in a known volume of wine and replace the lost volume with distilled water. The RISE in gravity can be converted into ABV using a calculator). If there is no RISE in the SG after degassing (tho the loss of gas may make the hydrometer float lower) then you have lost no alcohol.

 

[RottenGrapeJuice]

Were you whipping the wine for an hour? If so, that's WAY overdoing it.

Degassing the wine is not a short term thing. Kit instructions typically state to stir the wine (using a drill mounted stirring rod) for 2 to 3 minutes, changing direction every 30 seconds. While this expels a lot of CO2, it does not get it all. It jumpstarts the process and the wine continues to degas over the next few days or weeks.

In recent years I degas all wines, as with the CO2 reduced, the gross lees drops faster without CO2 to hold it in suspension. I don't use a watch during degassing; I count. In reality I'm probably only stirring for 20 seconds in each direction, so I'm doing less than the 2 to 3 minutes. If I planned to bottle 4 weeks after starting, this may not be enough. But my current habit is to not bottle before 6 months (some reds a year) so it works fine for my needs.

Thanks for your insight. I had two 6 gallon carboys, for which I did 20-25 minutes each. And when I say 20-25 minutes it’s like drill for 30 seconds, rest for a minute. Otherwise if I did it for 30 minutes straight my drill probably would have spontaneously combusted. A significant amount of foam was being created the entire time. Also, I degassed immediately prior to sulfiting thinking that will add an extra layer of protection against any potential oxygen exposure during the degassing process.

 

[Rice_Guy]

I am using vacuum;
* really doesn’t take an expensive pump to pull out 200 ml of volume,
* if you are serious you should get a few check valves, a liquid trap and a vacuum gague(s) see photo. ,, Much of what I do is pump it out a few minutes, do something and pump a few more minutes. My target for good enough is to have it hold a 5 inch Hg for thirty minutes (AKA hold in the bulb on a headspace eliminator thirty minutes)
* a carboy is bulk material, it either takes tome for gas to diffuse or mixing, I intentionally let CO2 in the carboy till the week when it is bottled. Check valves are on year old storage carboys.
* running vacuum for any appreciable time requires using natural gas techniques, ie white Teflon tape doesn’t work, silicone tubing is better than brass/ nylon tubing fittings

* yup it always foams , , , see video on PM, it won’t load here

 

[winemaker81]

Thanks for your insight. I had two 6 gallon carboys, for which I did 20-25 minutes each. And when I say 20-25 minutes it’s like drill for 30 seconds, rest for a minute.

That's way too much. As @Rice_Guy said, the wine will foam as long as you stir it. 4 to 6 iterations for 20-30 seconds each is all it takes.

 

[Johnd]

Typically, when I vacuum degas my wine, using this pump: 2.5 CFM Vacuum Pump , the vacuum line comes out of the carboy stopper, and goes into a 750ml wine bottle, with another line coming out of the bottle and directly to the pump. The 750ml bottle acts like a reservoir to maintain vacuum without but trapping foam or wine to mistakenly be sucked into the carboy line. This pump is capable of maintaining 29 inHg vacuum on a carboy indefinitely. The first time it's switched on to a fresh wine, (in a carboy about 3/4 full) the foam comes up to the top very quickly, and the pump is switched off until the foam settles. This process is repeated until the foam quits coming to the top. After repeating enough times, the foam doesn't rise to the top and the tiny foam creating bubbles are replaced by large bubbles that create no foam. At that point, the wine is sufficiently degassed and ready for fining agents or storage, whichever method you use to clear your wine.

 

[vacuumpumpman]

We will typically use the splash racking cane when transferring between vessels and this gets great results. I will have to use the vacuum release valve (to stop or limit the vacuum) to prevent any foam from entering thru the inlet of the bung. The headspace eliminator is a great tool for removing additional CO2 and protecting your headspace.

 

[RottenGrapeJuice]

We will typically use the splash racking cane when transferring between vessels and this gets great results. I will have to use the vacuum release valve (to stop or limit the vacuum) to prevent any foam from entering thru the inlet of the bung. The headspace eliminator is a great tool for removing additional CO2 and protecting your headspace.

View attachment 79775

See it’s interesting because I have gotten Results like that while vacuum transferring. However, for what I did above (not transferring and hooking up directly to carboy), it looked much different. Foam wasn’t produced, only larger bubbles that literally resemble water boiling/simmering. Clearly something different is happening, just curious why it makes a difference. Only thing I can think of is the act of transferring will agitate the wine while under vacuum, easily allowing the CO2 to escape.

 

[vacuumpumpman]

See it’s interesting because I have gotten Results like that while vacuum transferring. However, for what I did above (not transferring and hooking up directly to carboy), it looked much different. Foam wasn’t produced, only larger bubbles that literally resemble water boiling/simmering. Clearly something different is happening, just curious why it makes a difference. Only thing I can think of is the act of transferring will agitate the wine while under vacuum, easily allowing the CO2 to escape.

That is correct that = Only thing I can think of is the act of transferring will agitate the wine while under vacuum, easily allowing the CO2 to escape.

It is in the description on our website = Wine Splash Racking Cane removes CO2 during wine vacuum transfers

There is a complete thread that talks about the entire process

 

[ratflinger]

I tried using a vacuum pump for degassing for several batches. Sure, it made plenty of bubbles, but I never could see much difference between vacuum & time. I've gone back to strictly time and I have no issues with CO2, ymmv. I have never tried the AIO so can't comment except to say the theory is reasonable.

 

[vacuumpumpman]

I tried using a vacuum pump for degassing for several batches. Sure, it made plenty of bubbles, but I never could see much difference between vacuum & time. I've gone back to strictly time and I have no issues with CO2, ymmv. I have never tried the AIO so can't comment except to say the theory is reasonable.

Do you use your vacuum pump to transfer and bottle ?

If not we make all the attachments so you can use your vacuum pump -

 

[Rice_Guy]

in concept * you should think of your carboy as a series of layers like shale rocks, ,, a top which is in equilibrium with the outside ,,, a bit lower which is almost in equilibrium but the added pressure let’s more gas reside ,,, a next lower which has more pressure head (water column) therefore it’s equilibrium is a higher percentage gas ,,, etc etc. It is a spring with only air pressing on the top but all five or seven pressing the bottom.
* removing the atmosphere pressure directly affects the surface which causes it to seek a new equilibrium therefore we see bubbles form/ coalesce and froth. As with a spring lowering the surface pressure also is communicated to the bottom, but since it is layers the pressure difference is less so not much froth and smaller bubbles.
* NUCLEATION, bubbles like to form on something that is jagged/ crystalline for example if you vacuum degas till small bubbles are happening then drop in some sugar or potassium metabisulphite you will see froth again as the crystals sink. ,,, big bubbles suggest nucleation in your situation combined with an instant disequilibrium.
* MIXING, racking mixes so all wine is exposed to a condition similar to the surface layer, ,,, running a wine whip with vacuum will break layers and give uniformity, ,,, time with the equilibrium off will encourage mixing, a new equilibrium develops with thinner layers, ,, but degassing is still kinda slow, ,,, an interesting compromise would be vacuum till the froth is gone > wine whip mix till a vortex happens > vacuum till froth is gone > wine whip till a vortex happens, ,,, chances are good that you could generate your large bubbles after each mixing.

t looked much different. Foam wasn’t produced, only larger bubbles that literally resemble water boiling/simmering. Clearly something different is happening, just curious why it makes a difference.

 

[sour_grapes]

See it’s interesting because I have gotten Results like that while vacuum transferring. However, for what I did above (not transferring and hooking up directly to carboy), it looked much different. Foam wasn’t produced, only larger bubbles that literally resemble water boiling/simmering. Clearly something different is happening, just curious why it makes a difference. Only thing I can think of is the act of transferring will agitate the wine while under vacuum, easily allowing the CO2 to escape.

Here are a few previous posts of mine from the thread that @Johnd asked you to read. (Degassing in a carboy.... ) I think it may be relevant to your thinking.

When I first started playing with vacuum degassing, I pumped on my carboys for a long time. I kept seeing bubbles. I used a half-filled carboy so that I could slosh the liquid around, each slosh causing more bubbling. I was disappointed, as this seemed to go on forever (~30 minutes). My vacuum pump has an outlet hose, so I decided to "sample" the gas coming off. The gas coming off was acrid and biting -- CO2, I am pretty sure.

HOWEVER, there wasn't much of it. It took me an embarrassingly long hour or so to realize that the bubbles did not contain much gas. Although a bubble might be the size of a pea or a marble or so, I was at such a low pressure that there was not much actual stuff in the bubble.

But back to thinking about the liquids: Again, you can evaporate a liquid without boiling it. So, yes, I agree that if you remove the partial pressure of water and/or alcohol in the headspace, you will evaporate water and/or alcohol from your wine. Again, this could be done with a vacuum pump, or it could be done by leaving a glass of wine on your kitchen counter on a warm, dry day. You don't need to see a bubble for evaporation to happen.

Now, let's think about what it should mean if you DO see a bubble. Does that mean it is alcohol? No, it doesn't. Let's do a thought experiment. Imagine you have a bottle of pure ethanol, and you are drawing a vacuum on it, but you are at a pressure/temperature combination that is below the boiling point. The atmosphere (i.e., the headspace) will be full of ethanol vapor. Now, let's say an omnipotent being freezes time, goes into the bottle, and injects a bubble of pure ethanol vapor, then restarts time. What will happen to that bubble? Answer: it will collapse, and the vapor will re-condense into the liquid phase. It will not rise up to the surface. The vapor pressure of the ethanol inside the bubble is not high enough to withstand the pressure that the liquid exerts on it, so it collapses. (The definition of boiling is when the vapor pressure is high enough that the bubble does not collapse.)

So, in the real world, if you see a bubble during degassing (and you are not boiling the whole vessel) it is not a bubble of alcohol. It was some dissolved gas coming out of solution.

 

[ratflinger]

Do you use your vacuum pump to transfer and bottle ?

If not we make all the attachments so you can use your vacuum pump -

Steve, I use vacuum to bottle, otherwise I'm using a Pentair Sureflow transfer pump. I actually have your fittings for the vacuum transfer.

 

[wineview]

We will typically use the splash racking cane when transferring between vessels and this gets great results. I will have to use the vacuum release valve (to stop or limit the vacuum) to prevent any foam from entering thru the inlet of the bung. The headspace eliminator is a great tool for removing additional CO2 and protecting your headspace.

View attachment 79775

Steve
Do you sell #6 double drilled bungs? How much are they and what would shipping cost be to 12414.
Thanks

 

[wineview]

If I have a bottle between pump and carboy, can I degas a full carboy or do I need to lower the level of wine. Also, is there any danger of imploding a glass carboy.

Thanks