Quick question for everyone. I'm fairly new to home brewing only done a couple batches, some turned out ok and one horrible Haha! I just did my first batch of all grain and fermentation took off like crazy and had to use a blow off tube. Long story short after 7 days in primary I decided to put a standard airlock and broke it installing it so back to blow off in a bottle of sanitizer. Came home today and blow off tube was out of the water. Probably been 24 hours since it happened. Is it going to be contaminated or oxidized at this point? Thanks for the feed back!
Oxidation and contamination
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SoCal-Doug
Well-Known Member
You are *probably* ok. There may have been a layer of CO2 over the liquid and oxygen was not being forced in. Swishing or mixing in oxygen would be a nightmare and easily detectable in the final product. Either way, I would say continue as if nothing happened and see how it goes. After bottling or kegging, and a little time to relax, taste it. If you sense anything like stale or old, wet cardboard, sherry, papery, pineapple, decaying vegetables, or increased bitterness, harshness, it may be slightly oxidized.
Never heard the pineapple flavor before, is that a leading indicator before some of the more unpleasant flavors show up?
Your beer was overfilled with CO2 during the active part of fermentation and will be releasing some of that for weeks. With CO2 coming out, there won't be any oxygen getting in through the blowoff tube so just put the end back in the water to keep it that way and relax with a cold one.
There is no such thing as a CO2 blanket, gases mix.
Just because CO2 comes out, does not mean air is not comming in.
However, your beer will probably be fine. I would not worry abit over it.
Yes, gasses mix but not quickly. How quickly is the question and that has to do partially with how long the blowoff hose happens to be. Were it mine I would not worry a bit.
VirginiaHops1
Well-Known Member
I was going to say this. This 'CO2 blanket' thing is a myth, and probably proven so by the fact that we're not all dead here on earth. Oxygen will diffuse through CO2 and mix even though it's lighter. But if your beer is not being agitated not much of it is really exposed. Transfers are where beer is usually oxidized.
If the beer was still fermenting and outputting CO2 then I am pretty sure the oxygen cannot get in, the pressure is slightly higher inside the fermentation bucket than outside of it so the gasses are being blown away from it through the blow off tube. If the fermentation has stopped and pressure difference stabilizes then yeah, the gasses can mix freely in time.
SoCal-Doug
Well-Known Member
CO2 weighs 44 grams per mole. Oxygen weighs 32. If there are no factors to disturb the gases such as uneven convection or drafts, CO2 will absolutely layer below the O2 and not mix. YouTube up some chemistry lesson demonstrations of this. You can literally "pour" a glass of CO2 into another glass of just air with candle in the bottom, and the CO2 settles to the bottom and extinguishes the candle. If left alone without drafts or disturbances, the CO2 forms a lower layer with no O2 below its surface.
If it mixed, there would be no reason for us to flood our bottles, secondary's, and kegs with CO2 before filling or racking and would simply be a waste of CO2 while oxygenating the crap out of our beer.
It would also be near impossible to do open vat fermentation of beer and wine without some really nasty oxidation flavors, with the huge amount of surface area open to oxygen (they don't drain it while its still bubbling).
If it mixed, there would be no reason for us to flood our bottles, secondary's, and kegs with CO2 before filling or racking and would simply be a waste of CO2 while oxygenating the crap out of our beer.
It would also be near impossible to do open vat fermentation of beer and wine without some really nasty oxidation flavors, with the huge amount of surface area open to oxygen (they don't drain it while its still bubbling).
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Then you are pretty wrong. Even in capped bottles, with preassure, oxygen can get it.
Assuming you are talking about plastic bottles, that is seeping through the plastic directly into the liquid, and thats something that takes many months or even years to happen. When fermenting, there is a draft going away from the fermenter so oxygen would have to "swim upstream" to get in through the holes. Gas does not work that way.
*Edit* Actually now that I wrote this it got me thinking, are you absolutely sure that oxygen can get in from low atmospheric pressure into high pressure container and based on what? If oxygen would get in the pressure would INCREASE inside the bottle. It does not matter if they get mixed together or not there is now more gas inside than before. The whole idea fights against the basics of pneumatics and hydraulics that I know. Unless CO2 would be able to escape at same rate as O2 would get in.
*Edit2* aww hell, not even then unless something is pushing the O2 in, because thats not how transfer of power works. It goes from strong to weak, not other way around, its not a two way street. There is a lot of power stored in a pressurised bottle and that power has strong desire to expand (or explode), things are moving away from it and not in. Plastic permeates gas but in this case that gas should be CO2 leaving the bottle. I'm just a geek with unhealthy obsession to alcohol and not a real scientist so I may be missing something crucial (or answer lies somewhere else like chemistry) but until pointed otherwise and preferably provided sources to study on I have to call bollocks on your claim.
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I know that it might be unintuitive but it is a fact nevertheless.
Take a look at this for example.
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I am talking about glas bottles.
That is exactly how gas works. However unintuitive it might be.
I am not saying it is alot, I even said I would not worry about it but it is wrong to say that it is zero, it is not.
VirginiaHops1
Well-Known Member
I agree gases will behave this way in a vacuum, and perhaps in your completely airtight fermenter. But there's this idea that I've seen floated around here that the blanket will just sit there regardless, even when you open the fermenter to fiddle with your beer like dry hop, transfer, cold crash, etc. I'm pretty sure when you open it the vacuum is gone and the gases can and will begin to diffuse.
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Silver_Is_Money
Larry Sayre, Developer of 'Mash Made Easy'
"Brownian motion" will diffuse the gasses if nothing else does.
That said, go back far enough and beer brewing was done in open vats. I believe that Fuller's was still using open vats into at least the 70's, and they were collecting awards world wide for Fuller's ESB.
That said, go back far enough and beer brewing was done in open vats. I believe that Fuller's was still using open vats into at least the 70's, and they were collecting awards world wide for Fuller's ESB.
4of7
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It just part of the hobby, brewing going side ways.. Will the batch be ok.maybe.it is ok great learning curve.
VirginiaHops1
Well-Known Member
It seems like oxidation risk varies greatly by style. The newer styles that are supercharged with hops and adjuncts seem much more susceptible to oxidation/flavor loss.
Not that I consider myself an expert brewer and should be listened to, but my take thus far is to go for the low hanging fruit and not worry about it too much. I open the fermenter and drop in my dry hops without worrying. I have tried to utilize closed transfers from carboy to keg though, because it's not much more effort than racking with the cane into an open keg.
No it does not. When the gasses are left on their own devices with no draft they will mix, you proved that with that video of yours, I am not questioning that. What I am questioning is if one gas has power behind making it move from one place to another then the other other gas will NOT go against the draft but move along with it. It will certainly mix with the former gas but not inside the source of the draft but outside as it escapes into the free air. Hell, what you are suggesting would even render the gas masks questionable, those that rely on exhausting your waste CO2 by the pressure of your exhale, if the toxic gas would slowly seep in with every exhale you take.
