Here's some CO2 in action:
It isn't because air is disturbed by wind, it's because gasses mix homogeneously. The same effect will happen in a windless bubble full of air. If you inject LPG, it will initially fall and then eventually mix and remain mixed forever
Idk if anyone said instantaneous, maybe I missed that.Well, the constant mantra here is that gases mix so fast that it is useless to even try to inject CO2 or LPG over a liquid, because it will not form a layer over the beer or the photographic chemical. An experiment was shown at the beginning of this thread which would have demonstrated that.
I contend this is not necessarily true, and that gases do form layers. I produced, for those who are ignorant of this basic facts of life, demonstration of the obvious, which is that LPG is dangerous because it does collect to the ground, and that there are laws in many countries to face the safety risk, and LPG is a gas. Anybody who lives in Italy knows that, some people don't even want LPG cars to be parked in a condominium garage because they are afraid.
Now you tell me that, in fact, yes, the layer will initially form, but that gases will mix subsequently.
Now my question is:
1) do you have any experiment, paper, document that convincingly proves that? Because if it this the old theory of perfect gases, I think we already saw that doesn't apply?
2) When does "eventually" come, according to said paper? In the case of a layer of CO2 injected over beer, will they "eventually" mix after one day, two months, one hour?
In another thread it was shown by at least three homebrewers that filling the neck of the bottle with CO2 results in a much less oxydized beer, a beer which is very easily distinguishable either visually or in the taste test.
I am still waiting somebody who reconciles this empirical evidence with their theory based on gas equations that do not apply to the case in discussion, and do not apply to all gases at all.
In another topic, it was noted that one of the "problems" with homebrewing in 2020/2021 may be that there is "too much information" (or perhaps "too much discussion" or perhaps "too much debate").These things are possible with some basic process modifications that are not difficult or expensive or unachievable for most.
Well, the constant mantra here is that gases mix so fast that it is useless to even try to inject CO2 or LPG over a liquid, because it will not form a layer over the beer or the photographic chemical. An experiment was shown at the beginning of this thread which would have demonstrated that.
I contend this is not necessarily true, and that gases do form layers. I produced, for those who are ignorant of this basic facts of life, demonstration of the obvious, which is that LPG is dangerous because it does collect to the ground, and that there are laws in many countries to face the safety risk, and LPG is a gas. Anybody who lives in Italy knows that, some people don't even want LPG cars to be parked in a condominium garage because they are afraid.
Now you tell me that, in fact, yes, the layer will initially form, but that gases will mix subsequently.
Now my question is:
1) do you have any experiment, paper, document that convincingly proves that? Because if you say that based on the old theory of perfect gases, I think we already saw that doesn't apply.
2) When does "eventually" come, according to said paper? In the case of a layer of CO2 injected over beer, will they "eventually" mix after one day, two months, one hour?
In another thread it was shown by at least three homebrewers that filling the neck of the bottle with CO2 results in a much less oxydized beer, a beer which is very easily distinguishable either visually or in the taste test.
I am still waiting somebody who reconciles this empirical evidence with their theory based on gas equations that do not apply to the case in discussion, and do not apply to all gases at all.
Our discussion appears to live on two different levels: I bring forward real facts and others just wave their physics book, which has formulas which don't apply here and are not as universal as they think, as is proved by everyday experience.
Again the experience you have is not an inclosed space such as a Fermenter. Also the LPG fumes would in fact complete diffuse in an closed room where the leak has stopped.Our discussion appears to live on two different levels: I bring forward real facts and others just wave their physics book, which has formulas which don't apply here and are not as universal as they think, as is proved by everyday experience.
Once fermentation stops the blanket is overI did read through all of the replies, but I will point out that open bucket fermentation is real. In a room withoit air movement and while fermentation is active, there is absolutely a blanket of CO2. As activity slows, the it gets thinner but as long as it is being produced, the layer exists. Once it stops, air will mix in but the impact is negligible. Only if you disturb the wort by adding dry hops or stirring will oxidation become a problem. That said - closed transfers and oxygen exclusion when handling beer is critical.
I did read through all of the replies, but I will point out that open bucket fermentation is real. In a room withoit air movement and while fermentation is active, there is absolutely a blanket of CO2. As activity slows, the it gets thinner but as long as it is being produced, the layer exists. Once it stops, air will mix in but the impact is negligible. Only if you disturb the wort by adding dry hops or stirring will oxidation become a problem. That said - closed transfers and oxygen exclusion when handling beer is critical.
Focusing on the bottling technique (not the engineering or science that may be involved), it appears that the technique was effective - it was able to keep beer in bottles longer.Re: "In another thread it was shown by at least three homebrewers that filling the neck of the bottle with CO2 results in a much less oxydized beer, a beer which is very easily distinguishable either visually or in the taste test."
This is another thread I have to mark as ignore. Happy brewing everyone!
Not if the room is closed and there are a lot of buckets....Once fermentation stops the blanket is over
That layer is very visible and it's commonly referred to as Kräusen. It's not an "invisible layer of gas" but as a matter of fact it's a very visible layer of (CO2 filled) foam and trub and yeast. That is the (very visible) layer that is protecting the beer from oxygen ingress. The Kräusen itself is very exposed to oxidation as proven by the outermost layer turning darker or even black. Those are hop resins oxidizing as they are exposed to atmospheric oxygen since there is no "invisible blanket" of CO2 to protect the outer layer. If you remove the Kräusen or let it fall back into the beer at the end of fermentation the beer will be immediately exposed to oxidation, which is why in commercial open fermentations the beer is transferred to closed and purged maturation vessels as final attenuation draws near.I did read through all of the replies, but I will point out that open bucket fermentation is real. In a room withoit air movement and while fermentation is active, there is absolutely a blanket of CO2. As activity slows, the it gets thinner but as long as it is being produced, the layer exists. Once it stops, air will mix in but the impact is negligible. Only if you disturb the wort by adding dry hops or stirring will oxidation become a problem. That said - closed transfers and oxygen exclusion when handling beer is critical.
Once fermentation stops the blanket is over
I didn’t realize he said open fermenter. If the lid is closed the co2 will replace the o2 during fermentationThat layer is very visible and it's commonly referred to as Kräusen. It's not an "invisible layer of gas" but as a matter of fact it's a very visible layer of (CO2 filled) foam and trub and yeast. That is the (very visible) layer that is protecting the beer from oxygen ingress. The Kräusen itself is very exposed to oxidation as proven by the outermost layer turning darker or even black. Those are hop resins oxidizing as they are exposed to atmospheric oxygen since there is no "invisible blanket" of CO2 to protect the outer layer. If you remove the Kräusen or let it fall back into the beer at the end of fermentation the beer will be immediately exposed to oxidation, which is why in commercial open fermentations the beer is transferred to closed and purged maturation vessels as final attenuation draws near.
No, once again the blanket was NEVER there (see above).
You're missing the point here.Count me in the camp of those who can’t vote because the poll is overly reductive. Yes, CO2 doesn’t provide a perfect barrier, and opening your fermenter introduces some O2, so it is wise to limit how long you have it open, but don’t take the ”gasses mixing“ observation to mean that it is an instantaneous thing and that if you crack the fermenter for a few seconds that you’ve ruined your beer.
There are many factors that go into you final product (ingredient quality, recipe, and all other process details). If your goal is a better hoppy beer be concerned about all factors - obsession over this one factor isn’t the answer.
You're missing the point here.
There are many factors that go into your final product (ingredient quality, recipe, and all other process details). If your goal is a better hoppy beer be concerned about all factors - [...]
Discussing science can be interesting.
Pragmatic approaches to minimizing the effects of oxygen ingress can be useful.
Idk if anyone said instantaneous, maybe I missed that.
There has been plenty of evidence in this thread that shows the diffusion of gases. Under normal temperatures and pressure, these gases will not “settle” and separate again. Again diffusion does not happen immediately but let’s say you open your fermenter and the air that gets in will definitely diffuse within the day. Now the extent of air that got in, is more important. That is because diffusion WILL occur.
I fear you are trying to say unless someone can produce a specific paper that studies a specific interaction, then it can’t be true. However that a falsity in thinking because these are gas laws.
Depends on your math capabilities and understanding here, but here is a formula and chart for diffusion rate of gases
https://www.engineeringtoolbox.com/air-diffusion-coefficient-gas-mixture-temperature-d_2010.html
Yes, some people say that spraying CO2 in the neck of your bottle is useless, it's a myth that you can fill your neck with CO2, because of the laws of gas.
Under normal temperatures and pressure, these gases will not “settle” and separate again.
It is not clear to me if you agree that GPL "settle" initially or not.
Again diffusion does not happen immediately but let’s say you open your fermenter and the air that gets in will definitely diffuse within the day
You see, the "myth" that some people is trying to "burst" is that it makes no sense to inject CO2 inside the fermenter and close it immediately, or to inject CO2 inside your bottle and cap it immediately.
I fear you are trying to say unless someone can produce a specific paper that studies a specific interaction, then it can’t be true. However that [is] a falsity in thinking because these are gas laws.
Somebody said that GPL being a gas cannot form a layer.
Then somebody else admitted GPL will form a layer, but it also will after some while diffuse even though initially it collects on the ground.
The prevailing idea in this discussion, based on "these are gas laws", is that GPL will not collect on the ground.
Once it is shown that GPL does collect on the ground, and creates a hazard, and this is a fact of life, the further assumption is that, because of gas laws, GPL will mix again with air given time.
This might be true, or might be false, I don't know, so I genuinely would like to see some paper stating that. I suspect this doesn't happen at all, but it's a suspect.
The point is that the "general laws of gas", not being valid for GPL in the initial phase, might not be valid for GPL in the subsequent phase! The general law of gas does not explain that GPL collects to the floor and I don't see how could it explain that after that, after a while, GPL will diffuse again. I showed you empirical evidence that GPL does not obey to the laws of perfect gases. You have to show me some empirical evidence that after a while it will diffuse.
My contention is that waving gas laws (ideal-gas laws) doesn't always work because those laws do not apply to all gases and to all circumstances. Some people take them as the Gospel, but they are just instruments in the hand of the wise and knowledgeable physician, with a certain limited scope of validity.
Empirical evidence shows, in the case of beer just like in the case of GPL, that gases do form layers in a way that has an effect (on the beer, on the explosion). I find nonsensical that people uses the equations to deny empirical evidence.
This reminds me of that scene in the Life of Galileo by Brecht (or rectius in one of the versions), when Galileo invites two Dominicans, who said the moons of Jupiter (the "Medicean planets") could not exist, to just look in the telescope and see them with their eyes. The Dominicans reply that science is right and it cannot fail, while senses can fail, therefore even if the planets are visible, they might not be there, but could be the result of an illusion of the senses.
The problem with their reasoning is that they think that their "science" is right regardless of empirical evidence. They think they can be right a priori, because they trust what they call "science", what is written in their "book of absolutely right rules". Science is observation first, hypothesis and modelization after, and empirical demonstration through experiments (cimento) after. In the first and third stage you have the "facts" that you want to explain. You cannot explain regardless of facts!. Those equations have a meaning only insofar as they explain the facts.
The proof is in the beer!
So what are some pragmatic approaches (direct links to specific articles or book recommendations please) to minimizing oxygen ingress and/or mitigating oxidation?Gases will not mix until to expose them to each other. A sealed fermeter will be full of CO2. When you open it the CO2 and outside gasses will begin to mix.
Isn’t a constant cloud of gas near the ground = a blanket?A gas that is heavier than air, and that has a constant source, will collect at the ground while diffusion continuously occurs. If the source replenishes it faster than it diffuses, you will get a constant cloud of the gas near the ground.
So what are some pragmatic approaches (direct links to specific articles or book recommendations please) to minimizing oxygen ingress and/or mitigating oxidation?
Science is interesting. If engineering is converting science into useful things or processes, then maybe resources that talk about brewing engineering would be of interest to the forum.
How come I voted for blankets existing, but also agree entirely with @TheMadKing and @VikeMan‘s characterization of gasses?
Isn’t a constant cloud of gas near the ground = a blanket?
Now in a closed environment you have something else to consider: say you have 1 literof pure CO2 and you open the lid for a few seconds. In those few seconds diffusion occurred. 100% of the CO2 did not diffuse out, but some amount of air diffused in. Let's say for argument that 0.01 liters of air got in during those few seconds. Now the gas will homogenize and you will have a prefectly uniform mixture of CO2 and air that is 100 parts CO2 and 1 part air. Now if that mixture comes into contact with your beer, the newly introduced oxygen in the gas will oxidize your beer. It will not stay near the top where it first entered.
This is valuable, thank you for continuing to push for a more practical approach. Here are some processes that I use to minimize oxidation:
How come I voted for blankets existing, but also agree entirely with @TheMadKing and @VikeMan‘s characterization of gasses?
Isn’t a constant cloud of gas near the ground = a blanket?
Yes - completely agree. You’d need to replenish/purge the 0.01 l somehow to prevent oxidation before sealing the lid. But... how you answer depends on what you mean by “blanket” I suppose.Now in a closed environment you have something else to consider: say you have 1 literof pure CO2 and you open the lid for a few seconds. In those few seconds diffusion occurred. 100% of the CO2 did not diffuse out, but some amount of air diffused in. Let's say for argument that 0.01 liters of air got in during those few seconds. Now the gas will homogenize and you will have a prefectly uniform mixture of CO2 and air that is 100 parts CO2 and 1 part air. Now if that mixture comes into contact with your beer, the newly introduced oxygen in the gas will oxidize your beer. It will not stay near the top where it first entered.
@TheMadKing
Without quoting your last #102, what I get is that you do believe that it is possible to actually purge a volume and fill it with some gas, let's say CO2, which will be basically almost entirely CO2.
Some "perfect gas law" proponent here claimed in another thread this is not actually possible to purge a bottleneck because the gas you inject in the bottle neck will instantly diffuse in the atmosphere. I think we agree here.
Regarding diffusion of LPG after the initial collection on the ground, I certainly don't rule out that this is entirely possible, although so far I did not see anything in support of this, if not a generic belief that all gases mix uniformly given enough time, a belief which is based on the pure-gas equations, that certainly work in most cases, but I don't know whether it is true also for gases like LPG; but this is not the central point: The point here is that if time is needed for this diffusion to happen, then I, like other people using some chemical product, can purge a flask of chemical with LGP and close the cap, and I will have LPG inside the flask. And I can purge the bottleneck with CO2 and cap it and have much, much, much less air inside my bottleneck than if I had not purged it with CO2.
The common commercial oxygen target in the headspace of beer that I have seen is 0.01 parts per million to avoid staling. Now if you even open your keg for a second, it seems pretty likely that there is now more than 0.01ppm oxygen in your headspace.
This would be a very interesting discussion in another thread (How much oxygen is enough to spoil our beer) and I find it very interesting information.
Yet, I think you take this number too strictly.
If oxydation is nearly istantaneous (as somebody also claim) and it works on the entire content of the beer (as it appears to be generally cleaimed) as soon as you open your bottle, and even before you pour your beer in a glass, it would be stale. And not just a homemade raw-beer bottle, but also a commercial bottle.
Commercial producers aim high both because they can (their beer never sees "air", it's all a close circuit which recovers the CO2) and somehow because they must (their beer can travel for days under the sun or be stored and transported in the most punitive ways by certain customers). They aim at two years expiration date in possibly adverse conditions.
Our homemade bottle-refermented raw beer will probably be oxydized in 1 day if we put it on a truck and let it travel under the sun, shake etc.
And yet, even though oxydation certainly occurs in our bottle, I believe this is not an instantaneous phenomenon which takes place with 0,01 ppm in the bottle neck staling our beer. If you let a glass of beer exposed to air, it will take many hours to get darker (there is a brulosophy beerexperiment on this).
In another thread it was amply shown that purging the bottle neck with CO2 is definitely, and definitively helping the beer, which leads me to state that the purging operation is certainly useful, even though the complete elimination of air is never possible. It's a question of shades of grey, and we want to stay the more possible on the whitish side of grey.
Maybe another poll could be made: "do you believe that you can purge a container with CO2 and close the cap and in so doing greatly reducing the air content inside the container?" and "Do you believe that in so doing you reduce the oxydation of the beer to an extent which is perceptible in taste?"
@TheMadKing
I have never read in any thread in other fora (I am new here) that somebody has such an extreme idea of CO2 and heavy gases falling on the bottom with the same certainty that a liquid does.
The idea is generally that heavier gases will, with time, collect at the bottom if no perturbation is present. If you shake, gas mix. If you inject air, gas mix. The CO2 in gaseous form was used in the document to illustrate visually the behaviour that also LPG sports. It collects to the floor but it can be easily disturbed by a stream of air.
No no no
Heavier gasses will NOT collect at the bottom with time. They will mix with time, on their own, without any shaking, mixing, turbulence, etc.
This is the critical point to understand. Gas molecules have energy. The higher the temperature of the gas, the more energy the molecules have. They are constantly moving and bouncing off each other. This energy causes gasses (all gasses, because it is a property of this state of matter) to mix on their own without any external influence. This is a gas law - which means that is has been experimentally demonstrated to be true in all cases, so many times and so thoroughly that it has been deemed a law and not a theory.
I also don't care to debate the applicability of every mathematical proof.
The van der Waals equation starts from the ideal-gas equation and introduces three new variables, which are gas-specific. For certain gases those values are such that the behaviour of the gas approximates an ideal gas, for other gases they are very far and the behaviour of the gas is far as well from the behaviour of an ideal gas. LPG, butane and propane being an obvious example from the real world.
Is there something in the Van der Waals equation that suggests the heavier gas settling you keep referring to? Please be specific.