Degassing in a carboy....

[masic2000]

I am experimenting with a shop vac and a home made vacuum pressure regulator using an old air lock with holes drilled on the sides (i'll try to post some pics if I can). I do not have a gauge attached so i'm not sure how much pressure i'm pulling. I have imploded one plastic carboy (transferring water initially . . .) so I know I cannot use full pressure to rack. But with some trial and error I was able to rack wine successfully without pushing the limits. At some point I'd like to know how much pressure I'm actually pulling.

 

[sour_grapes]

From Shopvac.com

• Sealed Pressure (SP) – Suction pressure measured in inches of water if you were to pick up a solid column of water straight up vertically. The number represents how many inches the water can be pulled by the pressure. Numbers >75 are considered the high end of utility vacuum cleaners.

75" of water is about 5.5 inHg (or 140 mmHg), or about 2.7 psig, or about 0.18 atmospheres below room pressure.

 

[masic2000]

Thanks sour. This is something I can try . . .

 

[cmason1957]

I'd doubt you will do anything with 2.7 psig. When I used to use the brake setup, I never got anything to come out before about 15.

 

[sour_grapes]

I'd doubt you will do anything with 2.7 psig. When I used to use the brake setup, I never got anything to come out before about 15.

I agree with your sentiment, Craig, but the maximum that is possible is 14.7 psig.

 

[cmason1957]

I agree with your sentiment, Craig, but the maximum that is possible is 14.7 psig.

Damn units. It has been to long since it mattered that I messed those up. And you are correct, once again, psig, mm. Whatever it takes.

(obscure reference to Mr. Mom. 220, 221 whatever it takes)

 

[vacuumpumpman]

he also mentioned that he imploded a plastic carboy - which is not a hard thing to do with vacuum. It took me YEARS to develop a system, NOT to implode a PET carboy while using the All in one Wine Pump -

 

[Kiazer]

Been at this for 3 years now with 25 or so kits and fruit wines under my belt. The Vacuvin (I'm on my second one) is a pain in the butt to use for degassing 6 gallon carboys but it does get the job done.

I whip mine in the carboy for 30 mins...

 

[bstnh1]

I use a stainless steel Mixstir in my drill and have never had a problem degassing. You just need to be careful with the speed of the drill so as not to create a big vortex and suck a lot air into the wine and mistakenly think the foam is from Co2.

 

[Rice_Guy]

I am experimenting with a shop vac and a home made vacuum pressure regulator using an old air lock with holes drilled on the sides (i'll try to post some pics if I can). I do not have a gauge attached so i'm not sure how much pressure i'm pulling. I have imploded one plastic carboy (transferring water initially . . .) so I know I cannot use full pressure to rack. But with some trial and error I was able to rack wine successfully without pushing the limits. At some point I'd like to know how much pressure I'm actually pulling.

The house vac I tried will pull 4 inches of vacuum. They operate with a centrifugal fan and are not as efficient as a piston pump with check valves (positive displacement pump).
If I wanted a cheap way to measure vacuum or pressure I would put together a “U” tube with water in it. The few posts in this thread about inches of mercury (Hg) go back to the 1800s when we thought mercury thermostats and mercury “U” tubes were ok. Haven’t looked for the conversion Hg to water but it is in feet. Our standard air lock will hold about 1 inch water column, or .1 kpa. CO2 wants to come out of solutions even at low pressure/ vacuum. It just takes more time.

All this said if a shop vac was what I had I would use it! ! ! , , ( and did before buying a pump! , , SO2 is nasty stuff on the lungs when starting a siphon by mouth.)

 

[Burton Kent]

The secret seems to be the amount of vacuum pressure applied to the must which has to be between 22 to 25 inches of mercury or inhg to those in the know, lol.

Hand helds give 12 to 18inhg, food savers go between 14 to 18inhg, Refrigeration pumps go up to 28.5inhg, the holy grail figure, I am told, is 23inhg.

Where did you find out about the 23inhg figure?

Very interested as I'm trying to find the right pressure for my vacuum. Some wines nearly explode with foam when I apply a vacuum. Others barely react and stay gassy. It's depressing.

 

[Carboy-Boy]

Regarding degassing using a vac pump, my experience is you need at least 25 inHg. Years ago when I started using a vac pump to degas, I like many others, were concerned about collapsing the carboy. I started with ~ 15 in Hg and worked up to the max my pump would pull (1/6 HP, single stage, 1.5cfm), or just a shade over 25 inHg. That seemed to be the ticket, as every degas stage since has been successful. As Burton mentioned, "some wines nearly explode". When this happens what I do is cycle the pump a number of times, relieving the vacuum each time. After 4-6 cycles degassing settles down. (Note: added a separation vessel to prevent liquids from entering vac pump - see pic). Never had a kit not respond to the degas cycle using 25 in Hg, as mentioned earlier some start more violent than others, but in the end they all degas in 60-90 minutes.

 

[Burton Kent]

Regarding degassing using a vac pump, my experience is you need at least 25 inHg.

60-90 minutes seems like a long time. I do know that the alcohol will boil from the low pressure but haven't seen specifics about when it'll happen.

 

[vacuumpumpman]

60-90 minutes seems like a long time. I do know that the alcohol will boil from the low pressure but haven't seen specifics about when it'll happen.

I was thinking the same thing - Typically only 3-4 vacuum transfers using the allinonewinepump will remove most all the CO2.

 

[Johnd]

I’ve posted the vacuum degassing article by Dan Pambianchi ad nauseum when this topic comes up, now it appears that it’s in a members only section of Winemaker Magazine. In short, you’re not going to boil off your alcohol.

I use a simple $99 vacuum pump which gets pretty close to 29 inHg and can degas any carboy of wine in minutes, period, alcohol intact. The key to not “exploding” the CO2 out of the wine is to use a simple inline valve which controls the strength of the vacuum. Start with the valve wide open and slowly close it, thus slowly increasing your vacuum and removing the gas slowly, not immediately.

 

[vacuumpumpman]

I’ve posted the vacuum degassing article by Dan Pambianchi ad nauseum when this topic comes up, now it appears that it’s in a members only section of Winemaker Magazine. In short, you’re not going to boil off your alcohol.

I use a simple $99 vacuum pump which gets pretty close to 29 inHg and can degas any carboy of wine in minutes, period, alcohol intact. The key to not “exploding” the CO2 out of the wine is to use a simple inline valve which controls the strength of the vacuum. Start with the valve wide open and slowly close it, thus slowly increasing your vacuum and removing the gas slowly, not immediately.

Johnd -
I noticed in the pic that he has no regulator - so he is running at full maximum vacuum - It is stated that he will run the vacuum pump for 60-90 minutes. If you remove the CO2 in minutes using a similar AC style pump. I have to ask if he is pulling bubbles out of the wine after that long of a time - what could he be pulling off then ?

 

[Carboy-Boy]

When I started using the vac pump did a little research. What I found was that ethanol vaporizes at 172 degrees F at sea level, at 25 in Hg it will vaporize at 79 degrees F. My wine is in the 64 - 66 degrees F range so no matter how long the degas process (at this temperature) the alcohol content should not be affected. At least that is the assumption I've been going on!

 

[Rice_Guy]

When I started using the vac pump did a little research. What I found was that ethanol vaporizes at 172 degrees F at sea level, at 25 in Hg it will vaporize at 79 degrees F. My wine is in the 64 - 66 degrees F range so no matter how long the degas process (at this temperature) the alcohol content should not be affected. At least that is the assumption I've been going on!

* A good assumption, you will not be able to measure a decrease in alcohol in solution , , , but if we had a university lab the actual decrease would be a few ppm.
GAS THEORY
* Water will dissolve 1.7 gram per liter of CO2 at 20C (room temp/ 1 atmosphere pressure) As the temperature decreases more CO2 will dissolve (roughly a log function) and as temp increases less will dissolve. As the CO2 comes out of solution it absorbes heat from the liquid which means that the solubility of the gas in your wine has increased ie the rate at which it comes out will decrease.
* We are pulling a vacuum which has the effect of increasing the rate at which the gas comes out, in this case it is linear to what is called the partial pressure. This is made up of the percent of CO2 in the headspace times the pressure in the headspace ie as bubbles start to come out the headspace will become enriched with CO2 and the rate decreases as we pull a gas out.
* The CO2 in the wine has reacted with water to create carbonic acid which reacts with the wine acids/ salts, drops the pH and technically is no longer a dissolved gas. All this works to come to equilibrium changing the chemistry as we try to degas our wine.
* As car-boy noted with his hardware / 25 inchesHg vacuum (0.16 atmosphere, ie 16% of normal pressure) it will take an hour to an hour and a half to get to the point where there isn’t an obvious release of gas bubbles. I am not surprised. All the equilibriums are being whacked out of balance and the 5 gallon mass will slow things down.

We have a fast way to do degassing when we vacuum transfer or a slow gentle way just by pulling a vacuum and even a more gentle way if we let it volitalize naturally at one atmosphere.
* All in all how anxious are we? , , The risk from racking/ transferring is that in the process we are exposing the wine to a new atmosphere which contains oxygen. This will follow the gas law like CO2 and some will dissolve. As with losing some alcohol we know it does happen , , but we probably wouldn’t be able to saturate the wine with oxygen, , just religiously added sulphites to take care of this, , and try to not over do the racking treatment.

 

[sour_grapes]

When I started using the vac pump did a little research. What I found was that ethanol vaporizes at 172 degrees F at sea level, at 25 in Hg it will vaporize at 79 degrees F. My wine is in the 64 - 66 degrees F range so no matter how long the degas process (at this temperature) the alcohol content should not be affected. At least that is the assumption I've been going on!

I don't think you have a big problem with your practices, but let me point out a problem in your reasoning. Let's consider water. It boils at 212F at sea level. Is it also your assumption, then, that if you set a dish of water out on your kitchen counter at 70F, it will never, ever dry out?

In your post, you used the word "vaporize" to mean, I believe, "boil." Essentially, there is nothing "special" about the boiling temperature. It is just the temperature where the partial pressure matches the ambient pressure. Liquids actually do vaporize at temperatures below the boiling temperature; they just do it more slowly.

 

[Carboy-Boy]

Thanks "Rice-Guy" and "Sour_Grapes" for your respective physics explanations! Just glad you didn't "burst-my-bubble", so to speak!