Degassing and oxidisation

I am An air conditioning engineer. This means I have lots of use full things kicking about in my van.

I have a vacuum pump for evacuating refrigeration pipe work, its a powerfull thing which is used to suck out moisture so can evaporate water at cold temperatures so i'm guessing can evaporate alcohol, with its lower boiling point. Has any one ever used some thing like this for degassing wine? I have seen methods using much smaller hand pumps over long periods of time. could this be a time saver and a half rugged up to a drilled rubber cork? can a Demi John cope with pressure of a vaccume?

I also have welding gear, which comprises oxygen and acetylene. Is this welding grade oxygen any good for oxygenating at the start? Would I just blast it threw an air stone for a few seconds? Any one use pure oxygen for this?

I would not pull a vacuum on a glass carboy or demijohn, at least not indoors. Those things aren't really rated for pressure, so the roughly 14psi it would encounter with a deep vacuum pulled on it might be enough to fracture it.

I think some people do use welding cylinder oxygen to oxygenate, as long as it doesn't contain anything else. I've not used it but of course many things that are normally not flammable will burn quite readily in oxygen, and any hint of oil or grease impinging in the line I think can cause a nice energy release.

Right for getting the moisture out of an A/C system it relies on getting the boiling point of the water to be above the ambient temp. So if it is at 70F ambient and you can get the water boiling point lowered to 60F with a deep vacuum then the water in the system will boil off, and if the vacuum is left on for long enough time, it will travel toward the vacuum and then out of the system.

What are you talking about? I use a medical vac pump to pull vac on my glass carboys for degassing purposes all the time. Granted, it's probably not as much vac as an HVAC pump might pull, but...

ETA: I would not use welding grade O2 to aerate, though.

I'm not saying it would fracture it, I'm just saying right on the packaging it says not for pressurized liquids. Just because someone does something all the time and hasn't yet had a problem with their particular setup doesn't necessarily mean it's safe or is a good idea. Just be aware of the risks and prepare accordingly and then if it ever does implode there will be no personal injury and the liquid will spill say into a rubbermaid container instead of all over the carpet or floor. Granted there is a couple psi of static liquid head when its full but that is less than the roughly -14psig when a deep vacuum is pulled.

Why wood you not use welding grade o2? Just a precautionary thing? I'll maybe give it a go with a one gallon batch, all my meads have been fermenting virtuously without it but I just wondered if it would speed it up. The medical vac will be similar. How long do you leave the pump on? Just until the co2 bubbles stop? I'll do it in the bath to be on the safe side. I love brewing in the bath anyway.

I recently tried my hand at vacuum degassing using a brake bleeder. According to the gauge I got my one gallon carboy to around 25in. Hg and everything was fine, aside from my forearms. I have now bought a vacuum ejector from Hong Kong and will connect that to my air compressor and achieve about the same vacuum without the sore arms

Harbor Freight has the venturi style vacuum things that will run off the air compressor and draw a pretty decent vacuum, not as deep as a refrigeration vacuum pump but not too bad.

How long do you leave it under a vacume? Was thinking if I hooked up 2 demijohns, one full one empty I could make a vacume and just leave it with the empty one their to fill with the co2?

huesmann said:

ETA: I would not use welding grade O2 to aerate, though.

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This is pretty much what everyone uses, and there's nothing wrong with it...it's a rare brewer who can get their hands on medical grade oxygen! I highly recommend the Williams Brewing oxygenation wand, that you use with this type of welding oxygen cylinder that you can get at any Lowes or Home Depot...

EDIT: for the OP, Williams also sells the aeration wand by itself without the small bottle regulator

Ah cool that's good to know. That wand looks like the sort of thing I was thinking of making out of an air stone and some rubber. My oxygen bottles are a bit bigger and have their own trolly but its the same stuff. That's good theirs says 50 seconds so if I blast it gently for a min or two It should do it. I take it oxidation before pitching the yeast only? You would not repeat until this 1/3 sugar break I keep reading about along with staggered nutrients? Just a Goood shake to get some co2 out

I have used a break bleeder in the past to degas wine. You don't want to create a really strong vac, but it can be done. It is important that your carboy is full up to the bell part of the glass. The curves make the top much stronger and you want to contain the vacuum there.

Some people go overboard when aerating, imo. Go get a length of tubing for your siphon and close off one end (hot glue guns work great), then poke a bunch of 1/8" holes around that end of the tube, going up a few inches. Then when you siphon it was splash all around and get plenty of O2 in the liquid.

mooney said:

Why wood you not use welding grade o2?

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I used to work at a compressed gas manufacturing plant. The only difference between industrial (welding) grade oxygen and medical grade oxygen is the cleanliness of the bottle it's put in. When you take your cylinder in to be filled they will vent it, pull a vacuum, then fill it with the same oxygen they would put in a medical grade cylinder.

The problem comes from contamination. If you run your oxygen tank dry before your acetylene runs out you can get some acetylene drawn into your oxygen tank.

mooney said:

Ah cool that's good to know. That wand looks like the sort of thing I was thinking of making out of an air stone and some rubber. My oxygen bottles are a bit bigger and have their own trolly but its the same stuff. That's good theirs says 50 seconds so if I blast it gently for a min or two It should do it. I take it oxidation before pitching the yeast only? You would not repeat until this 1/3 sugar break I keep reading about along with staggered nutrients? Just a Goood shake to get some co2 out

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Oxygenation is only needed at the start of fermentation...generally I do it before I pitch yeast, and if it's a mead (or higher gravity beer), I sometimes add a second burst of oxygen at 24 hrs when I add my first staggered nutrient addition. After that, specifically oxygenating is not necessary, and potentially could be harmful (actually oxidizing [a bad thing that causes off flavors] the brew, rather than oxygenating [a very beneficial, good thing] to give the yeast the benefit of that respiratory fuel).

When it comes to degassing, I do what I call the "fly by" technique...every time I go near the carboy I swirl the $h!t out of it. BTW, I do recommend usind a blow off tube rather than a regular airlock...with proper oxygenation and "fly by" degassing, you will blow out your airlock fluid and be constantly trying to replace it, even if you don't actually have foam blowing out (which you certainly could have as well...) I have never used one of the vacuum techniques, so I can't comment on that, but I have tried other mechanical means, aka a degassing wand, and they just seem to be more trouble than they're worth. For one thing if you're not extremely careful, you *will* be cleaning up a MEA (Mead Eruption Accident), and then there's the whole sanitizing the wand, opening the carboy, etc, etc...just more chances for contamination. I think I get pretty good degassing with my fly by swirling, but I suppose I should try one time using the degassing wand after I think I've degassed adequately with swirling, and see if I get anything else out with the wand...

Oh, and if you do add oxygen at 24 hrs, after fermentation has started, *definitely* do some sort of degassing first, and be very cautious with your oxygen flow rates...this process is also very prone to creating a MEA!

ThorGodOfThunder said:

Some people go overboard when aerating, imo. Go get a length of tubing for your siphon and close off one end (hot glue guns work great), then poke a bunch of 1/8" holes around that end of the tube, going up a few inches. Then when you siphon it was splash all around and get plenty of O2 in the liquid.

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I have to disagree...you need to research this more. It is physically impossible to get optimal levels of dissolved oxygen in your must/wort using mechanical agitation like this. I highly recommend that every brewer read the book Yeast (co-authored by Chris White, of White Labs). This book more than almost any other has changed my homebrewing for the better...if you treat your yeast well (proper pitch rates, oxygenation, nutrients, degassing, fermentation temps), your mead/beer/cider/whatever will be infinitely better, and will mature faster. I think the reason why mead has a reputation for taking forever to be drinkable is that people essentially (unintentionally) make every mistake you can possibly make with fermentation when making mead -- ferment a high gravity must with a single yeast packet, no oxygenation, and with no temp control. (Fortunately the staggered nutrient idea is becoming pretty widespread.) You can more cleanly get away with these things with most beers which have much lower OG's, but given the average OG of mead being over 1.100, you really need to control the fermentation well, and if you do, your mead will be very drinkable much sooner (months rather than years...)

Sorry for the rant...

biochemedic, I've got a roughly two day old mead going...a 3-gallon traditional. I initially stirred very aggressively as I was mixing the honey and water. After pitching the yeast I gently stirred it and let turned a small aquarium pump on that was hooked to a 4" long air-stone. I let the air-stone run for an hour. After that initial "aeration", twice a day I have stirred the must and turned the aquarium pump on for an hour. In a "newbies" guide I read it said to aerate for three days. I am planning on using the aquarium pump for the last time tomorrow morning which will be 72 hours after the initial yeast pitch and aeration. After that I will only stir gently for de-gassing purposes. Does this sound about right or have I introduced too much oxygen? I could stop using the pump now and it will have been used over a span of 48 hours for a total run time of four hours.

Thanks,
Ed

I'm not overly familiar with how to use a regular atmosphere air stone, so I'd have to do some reading up on that. I'm also not familiar with the protocol of oxygenating/aerating for up to 72 hrs, or what specific benefit that has to offer...from what I've read, the yeast really need the oxygen primarily in their initial reproductive stage before active fermentation. What I can also say though is that as long as the yeast is actively fermenting, I don't think you could terribly harm the mead with aeration. Whatever oxygen is introduced should be taken up by the yeast and/or scrubbed out by active CO2 production.

I checked my gravity on the 11/28/2012 and it was at 1.070 which was within .002 of my calculated 1/3 sugar break. This was roughly 3-1/2 days after pitching the K1V. After taking the sample I added 1-1/4 tsp of DAP, stirred the must a bit, ran the air stone for about 5 minutes and then pulled the air stone and tubing out, put the lid on tight, and installed an air lock on, Temperatures are currently running around 68F after starting in the 66-67F range. The only thing since locking it up that that I've done to it is to swirl the must around once a day. On 12/03/2012 the gravity was at 1.024 and with a pH of 3.6. It seems to be going well.

From what I (a newbee) understand, aerating periodically over the first 72 hours is to help the yeast reproduce their numbers without struggling for oxygen. Once the initial reproduction boom of the yeast is over with the yeast don't require that much oxygen and oxygen then becomes a liability in regards to oxidation so aeration is halted. At least that's what is echoing around in my cavernous mind.

Ed