Kegging failures <- please advise

[RobbieOByrne]

Well I broke down and went full Keg. Bottling is nice but not as cool as a keg and keg bottling. I'll list what I got;

2 - corny kegs (homebrew shop said GTG, tested, trusted)
1 - CO2 Regulator w/ attached tank reg bracket (I can adjust pressure on each tank, wanted this incase I go big)
1 - 5 pound CO2 tank.
1 - Giant cooler for drinking time, I don't have room for a kegerator. (From what I've read and been told that as long as I chill before using the kegs and I keep then under CO2 pressure they can sit at room temp for a while).

The plan was to slow carb my tanks, while I wait for my "forced" diet to end. So I set them to 10 pounds each. With a gradual increase in pressure to drinking levels a week or so before drinking time.

There was a leak and about 3 days ago I found my tanks pressure sitting at 0. Over the period of a week and a half god knows how much of the 5 pound tank I inhaled, luckily it was sitting right next to a open window the whole time.

I cannot tell if the leak is at the tank/reg connection, keg/reg connection or keg. I'm assuming its coming from the tank/reg connection, both tanks dropped to 0, which means its not a single tank problem to me... and I can't test for leaks until I fix problem 1.

Problem 1 - went to Praxair, for refill of CO2, instead of beverage grade... they decided to give me industrial grade. Imagine my surprise when the faint smell of spearmint filled the area when I purged my reg, luckily the dirty CO2 never hit my precious beer.

Question: Isn't it illegal to fill industrial CO2 into a clearly marked beverage CO2 tank? What's the process of removing industrial co2 and purifying my tank?


Problem 2 - My beer is possibly sitting with oxygen in the keg. I can only hope that there is enough CO2 in the keg to keep the oxygen out. But lets assume the worse.

Question: Oxygen on the beer does what? I assume it increase decay process?


Thanks for the advice and information!

 

[bja]

Co2 is Co2. There's no such thing as industrial grade and beverage grade. It's all the same. Of course, this is apparently in California, so who knows what those idiots are doing there.

 

[Yourrealdad]

I don't know how it works for you, but I can't get a "refill" of co2. You can swap your tank out for a full tank kinda like propane (yes, I know you can get propane refilled). I bought a brand new shiny tank from amazon and then tried to get it filled and they said nope, unless I wanted to have them ship it away and charge me an extra $40. So you should just go and exchange your tank for a new one. Kind of like a core swap. No need to worry about cleaning out your new one just swap tanks.

Second you need to put soapy water or star san water at all of your connections to check for leaks. Obviously make sure they are tight enough to begin with. Oh and any part that you are connecting, ie regulator to tank, does not use teflon tape. Just the threads.

Yep oxygen is going to increase staleness. Pull up SLIGHTLY on the relief valve on the keg. If you hear co2 escaping you have co2 in there and don't worry about oxygen, if no noise, most likely full of air.

Hope some of this helps

 

[RobbieOByrne]

Co2 is Co2. There's no such thing as industrial grade and beverage grade.

I'm sorry but yes their is. Industrial is around 99% pure food grade aka beverage is 99.9% pure. Mostly the impurities are nitro and other none issue impurities. However there are several impurities lurking in that .9 % that will ruin the flavor of your beer or make you sick.

"One impurity that all homebrewers should be aware of is benzene. Benzene is a no-no for homebrewers. If the CO2 that you are purchasing has high benzene levels, it will leave you and fellow drinkers with terrible headaches. When I say high levels, we are not talking about much. Benzene is usually an impurity that is referred to in PPB. The benzene level should be around 20 PPB."

http://www.thebrewingnetwork.com/BN-Army-Blog/C02-Myths-and-Rumors

Finally besides carcinogens benzene. I just don't want my beer tasting like spearmint, oil, or other chemicals.

 

[bja]

I'm sorry but yes their is. Industrial is around 99% pure food grade aka beverage is 99.9% pure. Mostly the impurities are nitro and other none issue impurities. However there are several impurities lurking in that .9 % that will ruin the flavor of your beer or make you sick.

"One impurity that all homebrewers should be aware of is benzene. Benzene is a no-no for homebrewers. If the CO2 that you are purchasing has high benzene levels, it will leave you and fellow drinkers with terrible headaches. When I say high levels, we are not talking about much. Benzene is usually an impurity that is referred to in PPB. The benzene level should be around 20 PPB."

Finally besides carcinogens benzene. I just don't want my beer tasting like spearmint, oil, or other chemicals.

I've seen this quote before and IIRC it's BS. Where does this benzene come from?

Around here there is only one grade of Co2.

 

[IslandLizard]

If your kegs were purged from air and contained CO2, after the leak emptied your tank, there's no reason air can go inside. DO NOT pull the release ring, it won't make it better.

Depending on the area you live in, there may not be many filling stations. Look in the yellow pages (yup, I still use the paper ones) under "gas - industrial...", "welding supplies...", or "fire protection equipment..." and call around. You may find some places that fill. Many only do swaps as it is more convenient for them. Prices vary widely, so ask what it cost to refill or swap 5#, 10#, or 20# of gas, whatever your tank holds. I was quoted between $23 and $86 for the same 20# refill or swap. I found a place that actually charged $21 for walk in refill. It's a fire protection equipment company and they had 800-some bottles of all sizes on the floor.

You need to get the tank filled before you can do leak testing. There's supposed to be a washer (fiber or nylon) between the tank and regulator coupling, and the nut should be nice and tight (wrench). No teflon tape on the threads there, but it should be everywhere else there are threads, unless it's a compression or flare coupling, with appropriate (nylon) seal.

I have had leaky lids, posts, poppets, QDs, MFL connectors, and even a leaky (actually very touchy) pressure relief valve on my regulator. Start hunting, and good luck.

 

[govner1]

All of the above plus make sure you open the valve on your tanks ALL the way. If not, they will leak.


Sent from my iPhone using Home Brew

 

[peterj]

The plan was to slow carb my tanks, while I wait for my "forced" diet to end. So I set them to 10 pounds each. With a gradual increase in pressure to drinking levels a week or so before drinking time.

There was a leak and about 3 days ago I found my tanks pressure sitting at 0. Over the period of a week and a half god knows how much of the 5 pound tank I inhaled, luckily it was sitting right next to a open window the whole time.

You said you don't have a kegerator right? So are you trying to carbonate at room temp? If so 10 psi is nowhere near high enough pressure to carbonate the kegs. They would need to be at around 30 psi for 2-3 weeks at room temp. Here's a good calculator for it if this is the case: http://www.brewersfriend.com/keg-carbonation-calculator/.

 

[Ilan34]

All of the above plus make sure you open the valve on your tanks ALL the way. If not, they will leak.


Sent from my iPhone using Home Brew

Is this true? Just started kegging, first time I'm reading this. I don't think mine is all the way open, I was feeling a little cautious about doing that.

 

[bja]

Is this true? Just started kegging, first time I'm reading this. I don't think mine is all the way open, I was feeling a little cautious about doing that.

Yes. Same with propane tanks.

 

[Ilan34]

All of the above plus make sure you open the valve on your tanks ALL the way. If not, they will leak.


Sent from my iPhone using Home Brew

Is this true? Just started kegging, first time I'm reading this. I don't think mine is all the way open, I was feeling a little cautious about doing that.

 

[flars]

If your kegs were purged from air and contained CO2, after the leak emptied your tank, there's no reason air can go inside. DO NOT pull the release ring, it won't make it better.

Depending on the area you live in, there may not be many filling stations. Look in the yellow pages (yup, I still use the paper ones) under "gas - industrial...", "welding supplies...", or "fire protection equipment..." and call around. You may find some places that fill. Many only do swaps as it is more convenient for them. Prices vary widely, so ask what it cost to refill or swap 5#, 10#, or 20# of gas, whatever your tank holds. I was quoted between $23 and $86 for the same 20# refill or swap. I found a place that actually charged $21 for walk in refill. It's a fire protection equipment company and they had 800-some bottles of all sizes on the floor.

You need to get the tank filled before you can do leak testing. There's supposed to be a washer (fiber or nylon) between the tank and regulator coupling, and the nut should be nice and tight (wrench). No teflon tape on the threads there, but it should be everywhere else there are threads, unless it's a compression or flare coupling, with appropriate (nylon) seal.

I have had leaky lids, posts, poppets, QDs, MFL connectors, and even a leaky (actually very touchy) pressure relief valve on my regulator. Start hunting, and good luck.

Yes, to all of this.

When you find a place that will refill the tank, test the tank fittings with soapy water while you are there. Tell them what the problem was. If the tank fittings are leaking, they will probably fix it on the spot.

 

[Peyope]

You said you don't have a kegerator right? So are you trying to carbonate at room temp? If so 10 psi is nowhere near high enough pressure to carbonate the kegs. They would need to be at around 30 psi for 2-3 weeks at room temp. Here's a good calculator for it if this is the case: http://www.brewersfriend.com/keg-carbonation-calculator/.

Came here to say this . Investing in a chest freezer is not that expensive comparing to the rest of your setup . I got a new chest freezer for $170. Fits two carboys .

 

[Rockn_M]

Kegging is a great time saver but there is a learning curve. Here are a few things that I have learned over the last few years:

1) For me exchanging the co2 tanks are much easier. The closest place for a refill is about 30 min away and the closest exchange is about 2 min away. If the co2 has any type of smell your beer will taste like the smell once it starts to absorb the co2.

2)If you are carbing at room temperature 10 psi is not going to be enough pressure. You will need a calculator to see what pressure to set when your beer when the beer is at a particular temperature. Just remember that as you cool your keg down for drinking you will need to adjust your psi. I set my regulator around 10 psi and around 40 degrees and let it set there for about 2 weeks and I get perfectly carbed beer.

3)Once your beer is fully carbed your keg can sit for months at room temperature without any issues. Just make sure it is fully carbed. Because if there is more pressure outside the keg than inside the o-ring can relax a bit allowing air to get in the keg and the beer to become flat. If your beer is exposed to the oxygen for a while it can also be come oxidized. If your beer is oxidized it can have a bad carboard taste but this can take a long time to show signs.

 

[kombat]

Well I broke down and went full Keg.

Good for you, welcome to the club!

I don't have room for a kegerator.

Hmm, so I guess not full keg then, eh?

Giant cooler for drinking time (From what I've read and been told that as long as I chill before using the kegs and I keep then under CO2 pressure they can sit at room temp for a while)

I'm a little confused about this. Is the plan to store the kegs of beer at room temperature, and then on nights when you plan to drink some, you'll move them into some sort of cooler, dump in a bunch of ice, and try to chill the whole thing down? Then what, let it warm back up again the next day? Can you clarify this part of the plan?

Do you have a refrigerator in which you can keep the kegs cold, even if it's not outfitted with taps?

The plan was to slow carb my tanks

There's no benefit to carbing extra-slowly. Just set them to the proper pressure right off the bat, then wait a week or two and they'll be fully carbed. Note that the "proper pressure" depends heavily on the temperature of the beer. I keep my kegs in the fridge at around 34 F and just leave them on 12-15 psi of CO2 at all times.

There was a leak and about 3 days ago I found my tanks pressure sitting at 0.

That sucks, but if it makes you feel better, every kegger's been there. It's almost a rite of passage.

Over the period of a week and a half god knows how much of the 5 pound tank I inhaled, luckily it was sitting right next to a open window the whole time.

LOL, why, what are you worried about? CO2 isn't poisonous, you're exhaling it right now. You're dissolving it into your beer, but you're worried about inhaling it? Granted, if you inhale an atmosphere of nothing but CO2, you'll pass out, but at the rate of a slow, week and a half leak from a 5 lb tank, the amount would be totally negligible compared to the amount just floating around the atmosphere anyway.

I cannot tell if the leak is at the tank/reg connection, keg/reg connection or keg. I'm assuming its coming from the tank/reg connection, both tanks dropped to 0, which means its not a single tank problem to me... and I can't test for leaks until I fix problem 1.

As another poster noted, there should be some sort of nylon washer that sits at the connection between your tank and the regulator (unless your regulator has an integrated O-ring, as is the case with my Taprite regulators). After that, make sure all your hose/fitting connections are as tight as possible. Make sure the posts on your keg are snugged up nice and tight. Finally, make sure the pressure relief valve on your keg lid is screwed on tight.

After checking all of that, get yourself some keg lube, and use it on all rubber O-rings in your keg, especially the big one around the lid. That stuff is magic. Finally, once you've tighted every connection, snugged down every post, and lubed up all your O-rings, put the whole thing under pressure and get yourself a spray bottle full of Starsan and spray everywhere you could potentially have a leak. Look for bubbles. That's where your leak(s) is(are).

Problem 1 - went to Praxair, for refill of CO2, instead of beverage grade... they decided to give me industrial grade.

I'll defer to the expertise of others on this one, but count me as one who was unaware that there could be two grades of CO2. CO2 is just what it is - CO2. It's a gas, a molecule. You can't make different CO2 depending on the use any more than you can make different oxygen (one for welding, one for scuba diving). It is what it is. I get my tank refilled at a place in town that fills fire extinguishers, and they've never asked me whether I wanted "beverage grade or industrial grade." They just give me CO2.

Question: Oxygen on the beer does what? I assume it increase decay process?

It oxidizes the beer, giving it that "wet cardboard" taste. If your tank hit 0 while it was connected and open, then you have no pressure in your kegs. However, assuming you properly purged the kegs when you first hooked them up, then there should be very little oxygen in the kegs, and they would instead simply have CO2 in their headspace. No pressure, but still just CO2. If your leak was on the tank/regulator end of things (i.e., at the tank/regulator connection, or the hoses), then the kegs should be fine, and that CO2 will sit in there indefinitely. If, however, your leak was at the keg itself (i.e., post not tightened down, leak at the lid O-ring, etc.), then there will be a tiny amount of gas exchange occurring, slowly replacing that CO2 with regular air (i.e., oxygen). But the amount/rate will be so low as to be negligible. I wouldn't worry about it, just DON'T OPEN THE KEGS until you get that tank refilled and identify and fix the leak.

 

[fantomlord]

I'll defer to the expertise of others on this one, but count me as one who was unaware that there could be two grades of CO2. CO2 is just what it is - CO2. It's a gas, a molecule. You can't make different CO2 depending on the use any more than you can make different oxygen (one for welding, one for scuba diving). It is what it is. I get my tank refilled at a place in town that fills fire extinguishers, and they've never asked me whether I wanted "beverage grade or industrial grade." They just give me CO2.

different grades of chemicals (which CO2 is) generally are different with respect to their overall purity, and/or levels of specific impurities.

 

[sandyeggoxj]

I was told by air gas that it is all the same gas they are putting in the tank. The difference is how the tank is handled. Certified food grade has rules on how the tanks are vacuumed prior to fill to minimize impurities.

 

[bja]

different grades of chemicals (which CO2 is) generally are different with respect to their overall purity, and/or levels of specific impurities.

Have you ever bought co2?

 

[fantomlord]

Have you ever bought co2?

I have, though I don't know what that has to do with my post. I was simply explaining how/why there can be different grades of CO2, even though they are all the "same molecule."

 

[bja]

I have, though I don't know what that has to do with my post. I was simply explaining how/why there can be different grades of CO2, even though they are all the "same molecule."

As explained in the following quote, purity has nothing to do with it.

I was told by air gas that it is all the same gas they are putting in the tank. The difference is how the tank is handled. Certified food grade has rules on how the tanks are vacuumed prior to fill to minimize impurities.

 

[fantomlord]

As explained in the following quote, purity has nothing to do with it.

yes it does. if it's 99% pure, but has 1% O2, that's different than being 99% pure with <0.1% O2 (arbitrarily chosen numbers to illustrate my point)

yes, they're both CO2, but no, they are not both good options for kegging your beer.

 

[GilSwillBasementBrews]

OP this might help you at if you are carbing at room temps so you know where to set your psi for the volume of co2 as per your room temp.


Sent from somewhere to someone

 

[bja]

yes it does. if it's 99% pure, but has 1% O2, that's different than being 99% pure with <0.1% O2 (arbitrarily chosen numbers to illustrate my point)

yes, they're both CO2, but no, they are not both good options for kegging your beer.

Unfortunately you don't have a choice between the two when you buy co2. You get what they have and I can guarantee you if you ask them they will tell you it's 100% pure.

I'm finding it hard to believe that you've bought co2 before.

 

[flars]

Unfortunately you don't have a choice between the two when you buy co2. You get what they have and I can guarantee you if you ask them they will tell you it's 100% pure.

I'm finding it hard to believe that you've bought co2 before.

CO2 may have met the purity standards for the food and beverage industry when it left the production plant, but mishandling afterwards may make if unfit for the food and beverage industry.
http://www.foodsafetymagazine.com/m...rage-technologists-carbon-dioxide-guidelines/

 

[fantomlord]

Unfortunately you don't have a choice between the two when you buy co2. You get what they have and I can guarantee you if you ask them they will tell you it's 100% pure.

I'm finding it hard to believe that you've bought co2 before.

not sure why it's so difficult to believe...and if you read my first post carefully, you'll see that I was actually speaking in generalities.

 

[RobbieOByrne]

Please refer to CO2 Wars in kegging section for discussion on CO2. Thanks for all the info from everyone.

 

[Trencher]

LOL, why, what are you worried about? CO2 isn't poisonous, you're exhaling it right now. You're dissolving it into your beer, but you're worried about inhaling it? Granted, if you inhale an atmosphere of nothing but CO2, you'll pass out, but at the rate of a slow, week and a half leak from a 5 lb tank, the amount would be totally negligible compared to the amount just floating around the atmosphere anyway.

Please excuse the pedantry, but... CO2 is in fact poisonous, and not just dangerous when it replaces the O2 we're breathing. I have a friend who formerly worked in a big pharma lab, testing the effects of drugs on rats and mice. He explained how they would kill the critters at the end of a test by placing them in an airtight enclosure and changing the makeup of the air they were breathing, gradually replacing the nitrogen in their air with CO2. They died even though the available oxygen level never changed.

From http://chemistry.about.com/od/gases/f/Is-Carbon-Dioxide-Poisonous.htm:
"Carbon dioxide intoxication and carbon dioxide poisoning are independent of oxygen concentration, so you may have enough oxygen present to support life, yet still suffer from the effects of rising carbon dioxide concentration in your blood and tissues."

Not that there's anything to worry about from a leaking tank, unless your home is very small and airtight.

 

[augiedoggy]

Co2 is Co2. There's no such thing as industrial grade and beverage grade. It's all the same. Of course, this is apparently in California, so who knows what those idiots are doing there.

Yeah this is not true... "industrial grade" often has oil in it and is for machinery/welding use ...praxair is one of my customers so I already asked them about this since I had read it before as well...

 

[augiedoggy]

I really hate the fact that they took the edit button away... ^^ I feel I should add that the oil and contimanats found in the "industrial" grade of c02 could very well be from the use of different unsanitary machinery and handling techniques they may use in the filling process.... I do know you dont want that oil in your beer.

 

[ericbw]

CO2 may have met the purity standards for the food and beverage industry when it left the production plant, but mishandling afterwards may make if unfit for the food and beverage industry.
http://www.foodsafetymagazine.com/m...rage-technologists-carbon-dioxide-guidelines/

You linked that article as though it is a reference to what you're saying about mishandling. It doesn't support your statement at all, it's just an article about CO2 testing. It says that there can be impurities in it, so they have developed testing guidelines. The article is from 2001.

There never seems to be an answer to this question about industrial vs. food grade CO2.

 

[kombat]

I really hate the fact that they took the edit button away.

They took the edit button away?

I just went back and checked a post I made 2 days ago, and I still have an "Edit" button on it. Maybe it's a setting with your user profile?

 

[augiedoggy]

They took the edit button away?

I just went back and checked a post I made 2 days ago, and I still have an "Edit" button on it. Maybe it's a setting with your user profile?

Well I guess its just me but I lost my edit button.... likely because the script/ad/spyware blocker I use is no longer allowing it to load for some reason... There are usually 10 to twenty different spy/adware scripts from this forum which are showing in the yellow "noscript" bar from this website at any given time.
***EDIT** lol no sooner did I type this and send it My "edit" option reappeared after being gone for two days... weird. all I did was go to my "account" setting and look for some option that related to the edit feature (didnt find anything). when I hit the back button it was back.

 

[day_trippr]

Management fat-fingered a setting last night that took the Edit button away for all non-paying participants. This error was rectified earlier today...

Cheers!

 

[sandyeggoxj]

Back to the original post. I don't know your local laws. You can contact the supplier and see what they have to say. If they don't like your questions and don't want to answer them go somewhere else. CO2 should theoretically last for a long time. I have a 20# tank that I use to carb 2-6 kegs at a time at room temp and then a 10# and a 5# for inside the kegerator. I just refilled my 10# for the first time this year after dealing with around 100-120 gallons of home brewed, force carbonated beer. So that isn't bad.

Back to the food grade thing: AirGas, the company I deal with, marks their co2 with food grade ratings when they need. Here is an example: http://airgas.com/product/Gases/Industrial-Application-Gases/Carbon-Dioxide---Industrial/p/CD FG50

If you don't want to worry as much about things and where you buy your gas buy one of these do-dads: http://www.micromatic.com/draft-keg-beer/gas-equipment-pid-770SG-L1300.html. They are not cheap but can be helpful. If you decide you want that filter PM me. A good friend of mine is a Micromatic dealer and has some great prices on their products.

Kegging is a learning curve. That is how it seems to be for everyone. After you do it for a while you might look back at these questions that think they are elementary in nature. That is okay. We all have to start somewhere. Kegging has opened up a great new world for myself and that is something you will begin to realize as you move forward. I remember back to 2009 when I was trying to figure out what a volume was and how it referenced my beer. Now I don't even think about these things. I just "know" what I want and make it happen.

Like all things in this hobby: have fun, have a home brew, and go crazy with the obsession!!

 

[Tomwaters]

Scuba tanks are not filled with Oxygen. Compressed Air.
With Oxygen, there are 3 types (of the same gas) basically as stated, it's in the handling. (Not including LoX)
Oxygen for welding - nothing special to do
Medical Oxygen - The gas is dehumidified and therefore certified for medical use
Aviator's Oxygen - same as medical but the FAA, rather than the DEA are involved. More expensive for the same thing.
(Aviators oxygen is for the pilots o2 system. It is NOT what passengers get above their seats)
Also with AvOx, they get crazy if a tank runs completely empty because it will have to be re-hydro'd due to potential back flow of condensation.

Yes, I'm a flight attendant, and paramedic (and therefore a beer drinker)

Good for you, welcome to the club!



Hmm, so I guess not full keg then, eh?



I'm a little confused about this. Is the plan to store the kegs of beer at room temperature, and then on nights when you plan to drink some, you'll move them into some sort of cooler, dump in a bunch of ice, and try to chill the whole thing down? Then what, let it warm back up again the next day? Can you clarify this part of the plan?

Do you have a refrigerator in which you can keep the kegs cold, even if it's not outfitted with taps?



There's no benefit to carbing extra-slowly. Just set them to the proper pressure right off the bat, then wait a week or two and they'll be fully carbed. Note that the "proper pressure" depends heavily on the temperature of the beer. I keep my kegs in the fridge at around 34 F and just leave them on 12-15 psi of CO2 at all times.



That sucks, but if it makes you feel better, every kegger's been there. It's almost a rite of passage.



LOL, why, what are you worried about? CO2 isn't poisonous, you're exhaling it right now. You're dissolving it into your beer, but you're worried about inhaling it? Granted, if you inhale an atmosphere of nothing but CO2, you'll pass out, but at the rate of a slow, week and a half leak from a 5 lb tank, the amount would be totally negligible compared to the amount just floating around the atmosphere anyway.



As another poster noted, there should be some sort of nylon washer that sits at the connection between your tank and the regulator (unless your regulator has an integrated O-ring, as is the case with my Taprite regulators). After that, make sure all your hose/fitting connections are as tight as possible. Make sure the posts on your keg are snugged up nice and tight. Finally, make sure the pressure relief valve on your keg lid is screwed on tight.

After checking all of that, get yourself some keg lube, and use it on all rubber O-rings in your keg, especially the big one around the lid. That stuff is magic. Finally, once you've tighted every connection, snugged down every post, and lubed up all your O-rings, put the whole thing under pressure and get yourself a spray bottle full of Starsan and spray everywhere you could potentially have a leak. Look for bubbles. That's where your leak(s) is(are).



I'll defer to the expertise of others on this one, but count me as one who was unaware that there could be two grades of CO2. CO2 is just what it is - CO2. It's a gas, a molecule. You can't make different CO2 depending on the use any more than you can make different oxygen (one for welding, one for scuba diving). It is what it is. I get my tank refilled at a place in town that fills fire extinguishers, and they've never asked me whether I wanted "beverage grade or industrial grade." They just give me CO2.



It oxidizes the beer, giving it that "wet cardboard" taste. If your tank hit 0 while it was connected and open, then you have no pressure in your kegs. However, assuming you properly purged the kegs when you first hooked them up, then there should be very little oxygen in the kegs, and they would instead simply have CO2 in their headspace. No pressure, but still just CO2. If your leak was on the tank/regulator end of things (i.e., at the tank/regulator connection, or the hoses), then the kegs should be fine, and that CO2 will sit in there indefinitely. If, however, your leak was at the keg itself (i.e., post not tightened down, leak at the lid O-ring, etc.), then there will be a tiny amount of gas exchange occurring, slowly replacing that CO2 with regular air (i.e., oxygen). But the amount/rate will be so low as to be negligible. I wouldn't worry about it, just DON'T OPEN THE KEGS until you get that tank refilled and identify and fix the leak.