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I'll show you mine if you show me yours (pellicles)

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So you're quoting a 2007 AHA powerpoint presentation by Vinnie C. as a response to a link to a blog written by someone with a PhD in microbiology?

OK.
 
So you're quoting a 2007 AHA powerpoint presentation by Vinnie C. as a response to a link to a blog written by someone with a PhD in microbiology?

OK.
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Cherries and snot bubbles.

Bugfarm @9 months:
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Cuvée Rene dregs
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Loon dregs
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I never purged any of these carboys with co2 and all the beer turned out fine. I guess I got lucky 4 times in a row.
 
I never purged any of these carboys with co2 and all the beer turned out fine. I guess I got lucky 4 times in a row.

Never said that it would 100% ruin the beer if you didn't. Just said that letting in excess oxygen is a bad practice.
 
CO2 is heavier than air, so unless you are shaking the carboy, there is still a CO2 blanket over the beer. I cannot be positive but i would assume the entire headspace is purged with CO2 due to the fermentation.

The "CO2 Blanket" theory has been proven incorrect.

P.s. barrels are porous to air and let in oxygen naturally.

They are MUCH less permeable than a glass carboy and especially a plastic bucket. I can give you numbers, if you like.
 
The "CO2 Blanket" theory has been proven incorrect.



They are MUCH less permeable than a glass carboy and especially a plastic bucket. I can give you numbers, if you like.


Sources?


From what i have seen the CO2 blanket still exist and what has been stated is through being uncontained the CO2 can eventually disperse. So a beer left in an open container will not be protected by the CO2 blanket. But that isn't happening in the 2sec it takes to take a picture or pull a sample.

Plus, if glass is permeable by oxygen then why would pulling a stopper for 2sec change the amount of oxygen being introduced to the beer in any measurable way?
 
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I'm legit surprised if this is true. A bung hole is a bung hole.

Just look at the same powerpoint that FTowne cited. The information regarding permeability of different vessels is in there. You can also look in Wild Brews by Jeff Sparrow, which is where Vinnie C. got that information. FWIW, permeability is a function of the diffused gas getting into a set volume of liquid over a set time, so it's not JUST about the bung, even though length of seal and type of closure is quite important.
 
Sources?


From what i have seen the CO2 blanket still exist and what has been stated is through being uncontained the CO2 can eventually disperse. So a beer left in an open container will not be protected by the CO2 blanket. But that isn't happening in the 2sec it takes to take a picture or pull a sample.

Plus, if glass is permeable by oxygen then why would pulling a stopper for 2sec change the amount of oxygen being introduced to the beer in any measurable way?

If you understood gas dynamics/fluid mechanics, you'd know that most gases mix evenly when allowed to do so and given enough time. Glass has very low permeability, but the seal of the carboy is not solid glass. It is a silicon/glass interface. So too, is the airlock hole not solid glass. It is a plastic/silicon interface. So . . . you've got two seals where permeability is higher already.

In the case of removing the airlock to take what amounts to dick pics of your pellicle, however, you are certainly allowing gas (CO2 in this for instance) to diffuse, rather quickly may I add, into the ambient, as the ambient has much less CO2 per volume than does the carboy.

Again, is it going to ruin your beer? Maybe not. But it is never a good practice to let more oxygen into your beer than necessary because of how the microbes involved metabolize in an aerobic environment. FWIW, the presence of a pellicle already indicates than oxygen ingress is occurring, so if you're getting a pellicle quickly, you should probably examine why your vessel is letting in that much ambient air.
 
If you understood gas dynamics/fluid mechanics, you'd know that most gases mix evenly when allowed to do so and given enough time. Glass has very low permeability, but the seal of the carboy is not solid glass. It is a silicon/glass interface. So too, is the airlock hole not solid glass. It is a plastic/silicon interface. So . . . you've got two seals where permeability is higher already.

In the case of removing the airlock to take what amounts to dick pics of your pellicle, however, you are certainly allowing gas (CO2 in this for instance) to diffuse, rather quickly may I add, into the ambient, as the ambient has much less CO2 per volume than does the carboy.

Again, is it going to ruin your beer? Maybe not. But it is never a good practice to let more oxygen into your beer than necessary because of how the microbes involved metabolize in an aerobic environment. FWIW, the presence of a pellicle already indicates than oxygen ingress is occurring, so if you're getting a pellicle quickly, you should probably examine why your vessel is letting in that much ambient air.


Wow, you sound like a prick.

Yes I understand gas and fluid dynamics, maybe I should pull out my diffusion text book or fluid mechanics text book off the shelf. Though, that is missing the whole point. The discussion is based on if oxygen is getting into the carboy at a substantial rate when pulling the airlock off. From experience, I say this is not a problem. You are arguing nitty gritty science without taking into account each individual as a group. Plus you keep changing the discussion just to "prove" you are right (is this a beerandraiderfan troll account?). Where is that source you promised about a glass carboy being more porous than a barrel? I noticed you already changed that to talking about the bunghole. Which, well, if you understood aging of beer you would know that barrels have those too, and yes, they use silicone/rubber frequently.

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Getting back to my argument about oxygen being let in. As I stated, yes the CO2 blanket protecting the beer in an open environment is a myth, but in a closed environment it works. Well, or more accurately, in a closed environment where the head space is filled with CO2 (like in a carboy during and after fermentation) the liquid is protected by that volume filled with CO2. Secondly, carboys do have a slight pressure inside of them, small yes, but it is there. Therefore, when opening the bunghole you will have the air in the head space pushing out.

Can oxygen get into the carboy when opening the airlock? Sure, possible, but I would argue very insignificant. The reason I brought up the barrels and then readdressed your comment on the porous nature of carboys is because in these vessels natural state, oxygen can and most likely is being introduced.

So removing the stopper would have to provide substantial oxygen after a) passing through the slight positive pressure of the carboy after being exposed to the atmosphere for no more than 20sec, b) dissolve into the denser CO2 headspace, and c) do this at greater rate than what oxygen is already seeping into the beer environment. Hell we didn't even get into the introduction of oxygen during kegging and bottling, or how low amounts of oxygen is good for certain bacteria and yeast growth and development during this aging process.

My sour beers do get a pellicle quickly, that is because I pitch my "bugs" right at the beginning. I do not aerate my wort, but there will be some residual oxygen from the brewing process and in the carboy.

Lastly, I do not have a nail in my glass carboy to pull out when I want/need to sample. Therefore, to monitor how the beer is developing and assessing how much longer it should sit or if it should be packaged I must remove the stopper and pull a sample. At which point, I might take a photo. Sorry for partying.

Serious question. Do you brew? Sounds like you have a lot of book knowledge but you sound overly concerned about things that makes me wonder if you have the practical experience.
 
Wow, you sound like a prick.

Sorry. Don't mean to. Seriously.

Where is that source you promised about a glass carboy being more porous than a barrel? I noticed you already changed that to talking about the bunghole. Which, well, if you understood aging of beer you would know that barrels have those too, and yes, they use silicone/rubber frequently.

The citation is a couple posts up and I never changed anything. Vessels are not made of a solid substance because they need a port. When talking about permeability of the vessel, that port is implied.

Getting back to my argument about oxygen being let in. As I stated, yes the CO2 blanket protecting the beer in an open environment is a myth, but in a closed environment it works. Well, or more accurately, in a closed environment where the head space is filled with CO2 (like in a carboy during and after fermentation) the liquid is protected by that volume filled with CO2.

Again, there is no blanket. There is a mixture of CO2 and a small amount of oxygen diffusing into the carboy via the port.

So removing the stopper would have to provide substantial oxygen after a) passing through the slight positive pressure of the carboy after being exposed to the atmosphere for no more than 20sec, b) dissolve into the denser CO2 headspace, and c) do this at greater rate than what oxygen is already seeping into the beer environment. Hell we didn't even get into the introduction of oxygen during kegging and bottling, or how low amounts of oxygen is good for certain bacteria and yeast growth and development during this aging process.

Oxygen being "good" for bacteria is another discussion completely. Just because some microbes grow and reproduce better in aerobic environments does not mean that is good for the flavor profile of the beer. For more information on this, please see Pasteur Effect and Custers Effect.

My sour beers do get a pellicle quickly, that is because I pitch my "bugs" right at the beginning. I do not aerate my wort, but there will be some residual oxygen from the brewing process and in the carboy.

Again, D.O. during growth phases is quite different than D.O. afterwards. See the above cited effects.

Lastly, I do not have a nail in my glass carboy to pull out when I want/need to sample. Therefore, to monitor how the beer is developing and assessing how much longer it should sit or if it should be packaged I must remove the stopper and pull a sample. At which point, I might take a photo. Sorry for partying.

Get some CO2 and purge your headspace while sampling, then. It's a small investment and a better procedure.

Serious question. Do you brew? Sounds like you have a lot of book knowledge but you sound overly concerned about things that makes me wonder if you have the practical experience.

Brewing for the past 13 years. Sour and funky beers for the past 11 or so. Oxygen ingress is very much not minutia, btw.
 
Would very much like to hear what they have to say. Dollars to donuts they are doing everything that they can to keep oxygen out of their beers.
If CO2 is heavier than oxygen makes you think that oxygen is rushing into the headspace and displacing co2 at such a high rate?
 
If CO2 is heavier than oxygen makes you think that oxygen is rushing into the headspace and displacing co2 at such a high rate?

The "heavier" bit is a misnomer, or, at best, a misinterpretation. Just think of if you leave your burner on without lighting it. Propane is "heavier" than air, but it doesn't form a layer of propane on the floor/ground when it comes from the burner, does it? Propane diffuses from the source at an even rate throughout the air, just like the interaction between CO2 and O2/air in the headspace of a fermenter.

Also, in a closed environment, like a airlocked or bunged fermenter, the rate isn't high. It is a slow diffusion through the seals. Even so, there can be a significant amount of diffusion over time.
 
The "heavier" bit is a misnomer, or, at best, a misinterpretation. Just think of if you leave your burner on without lighting it. Propane is "heavier" than air, but it doesn't form a layer of propane on the floor/ground when it comes from the burner, does it? Propane diffuses from the source at an even rate throughout the air, just like the interaction between CO2 and O2/air in the headspace of a fermenter.

Also, in a closed environment, like a airlocked or bunged fermenter, the rate isn't high. It is a slow diffusion through the seals. Even so, there can be a significant amount of diffusion over time.
Yah I got it. But when you open the bunghole O2 rich air would diffuse into the carboy with CO2 rich air (or vice versa) pretty slowly, correct? I'm not understanding how taking the bunghole off for a few seconds every couple months is going to significantly expose your beer to enough oxygen that it will ruin it.
 
Yah I got it. But when you open the bunghole O2 rich air would diffuse into the carboy with CO2 rich air (or vice versa) pretty slowly, correct? I'm not understanding how taking the bunghole off for a few seconds every couple months is going to significantly expose your beer to enough oxygen that it will ruin it.

Then you don't understand how little oxygen it takes for brettanomyces to make acetic acid and ethyl acetate above threshold levels.

Pro-tip: it's not very much
 

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