superstock
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So for the home brewer, PET vessels, solid PET O ring bungs and dry one way airlocks are the recipe for the least o2 in the brew. Regardless of headspace.
60L fermentor
- Thread starter calobes
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No you're exactly right. At the end of fermentation, absolutely I don't want oxygen near my beer, but at the start, I like lots. My "square" beer gets siphoned after a few days, for that reason. That's what most uk breweries who use squares. But a blanket statement that oxygen is bad for beer is wrong.
Lord Raja Goomba I
Prisoner of Sobriety
Good response, Doc.
Yob
Hop to it
A goodly amount of info , while I take on board what's been put forward, I think it's a managed risk and what seems to have come to the top is that though there is a 'risk' it still seems negligible in a hb environment, certainly from a perception point of view.
Thanks to greg and doc for the info and entertainment..
I'm still not going to worry too much though and if I start to get infections I'll be sure to eat my words here
Thanks to greg and doc for the info and entertainment..
I'm still not going to worry too much though and if I start to get infections I'll be sure to eat my words here
TheWiggman
Haters' gonna hate
Signing in again...
I'd like to say that I value to input of Greg.L and it's clear you're no dope. The discussion here is valuable and I certainly was in the wrong with my original assumptions regarding pressures. Partial pressure is a dificult concept for me to grasp but the systems I deal with almost exclusively deal with flow conditions. Where flow doesn't exist, the principles change.
I completely accept and have accepted (after being corrected) that oxygen will get in. The matter remains though of headspace [volume] affecting a brew. Greg.L's comments are that oxygen is the enemy with regards to infections, and I'll take his word for it (though I can't find much about it online. Sanitation, yes, which is probably why so many members here are more concerned about that because by and large that's the message you get when sitting behind a keyboard.)
I'll disregard the area of a fermenter which is making contact with the wort. The rate of transfer will be constant regardless for a small brew.
The larger the surface area, the greater the rate of transfer of oxygen (as the permiability coefficient is [quantity x thickness] / [area x time x Δp] )
Doing some maths on paper the relationship between fermenter area : headspace is -
Surface area : headspace
d + 4·l : d·l
Where l is the height of the headspace and d is the diameter of the drum/fermenter.
What DrSmurto is talking about is managing the oxygen proportion within a headspace. The smaller the headspace, the easier this would be to manage. In addition if the vessel (cask, conical SS fermenter etc.) has any sort of taper at the top then by topping it up you are reducing the surface area of the liquid to the gas about it, which is favourable. This isn't typical of your standard home brew bucket or Coopers fermenter.
I completely understand that minimising headspace is ideal to manage the proportion of oxygen within that headspace.
As homebrewers with simple fermenters and no real means for managing the oxygen content, I'm still confident larger headspace won't increase the proportion of oxygen inside the fermenter's headspace. Quantity yes, proportion no.
All that aside the most important message I've got from all this discussion is to be careful about leaving fermented beer in an HDPE container for extended periods. This is a habit I have for lagers and is something I'll look at changing. Especially considering Greg.L's comments about the increased risk of infection with oxidation.
Attached is the maths for above for those interested. Not signing out.
View attachment 3791_001.pdf
I'd like to say that I value to input of Greg.L and it's clear you're no dope. The discussion here is valuable and I certainly was in the wrong with my original assumptions regarding pressures. Partial pressure is a dificult concept for me to grasp but the systems I deal with almost exclusively deal with flow conditions. Where flow doesn't exist, the principles change.
I completely accept and have accepted (after being corrected) that oxygen will get in. The matter remains though of headspace [volume] affecting a brew. Greg.L's comments are that oxygen is the enemy with regards to infections, and I'll take his word for it (though I can't find much about it online. Sanitation, yes, which is probably why so many members here are more concerned about that because by and large that's the message you get when sitting behind a keyboard.)
I'll disregard the area of a fermenter which is making contact with the wort. The rate of transfer will be constant regardless for a small brew.
The larger the surface area, the greater the rate of transfer of oxygen (as the permiability coefficient is [quantity x thickness] / [area x time x Δp] )
Doing some maths on paper the relationship between fermenter area : headspace is -
Surface area : headspace
d + 4·l : d·l
Where l is the height of the headspace and d is the diameter of the drum/fermenter.
- For a case where the headspace is very, very low, the surface area is much greater than the voume
- For a case where the headspace is infinitely high, surface area will be 4 x the volume.
What DrSmurto is talking about is managing the oxygen proportion within a headspace. The smaller the headspace, the easier this would be to manage. In addition if the vessel (cask, conical SS fermenter etc.) has any sort of taper at the top then by topping it up you are reducing the surface area of the liquid to the gas about it, which is favourable. This isn't typical of your standard home brew bucket or Coopers fermenter.
I completely understand that minimising headspace is ideal to manage the proportion of oxygen within that headspace.
As homebrewers with simple fermenters and no real means for managing the oxygen content, I'm still confident larger headspace won't increase the proportion of oxygen inside the fermenter's headspace. Quantity yes, proportion no.
All that aside the most important message I've got from all this discussion is to be careful about leaving fermented beer in an HDPE container for extended periods. This is a habit I have for lagers and is something I'll look at changing. Especially considering Greg.L's comments about the increased risk of infection with oxidation.
Attached is the maths for above for those interested. Not signing out.
View attachment 3791_001.pdf
Feldon
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Trying to replicate the stringent measures employed by commercial brewers to eliminate oxygen from their beers is all well and good. But does it really matter on the home brew scale?
My understanding is that chemical reactions that lead to stale oxidised beer occur faster if the beer is subject to high temps, agitation and light.
Commercial brewers have a much tougher job in making sure their beers reach their consumers without going stale. Its a rough world our there for commercial kegs and pallets of slabs due to the trauma of industrial transport and storage.
But for the home brewer, whose beers rarely travel more than several metres from where they are made, the rate of chemical reaction must be much reduced. And therefore stay fresher for longer. I think this is evidenced in practice by home brewers, most of whom I would think make their beers to be consumed fairly soon, whereas commercial brewers are aiming for as long a shelf life as they can manage.
So keep your home brew beers cool, dark and still.
And for bottlers, wouldn't the residual yeast used in bottle fermentation scavenge most or all of the oxygen dissolved in the beer?
My understanding is that chemical reactions that lead to stale oxidised beer occur faster if the beer is subject to high temps, agitation and light.
Commercial brewers have a much tougher job in making sure their beers reach their consumers without going stale. Its a rough world our there for commercial kegs and pallets of slabs due to the trauma of industrial transport and storage.
But for the home brewer, whose beers rarely travel more than several metres from where they are made, the rate of chemical reaction must be much reduced. And therefore stay fresher for longer. I think this is evidenced in practice by home brewers, most of whom I would think make their beers to be consumed fairly soon, whereas commercial brewers are aiming for as long a shelf life as they can manage.
So keep your home brew beers cool, dark and still.
And for bottlers, wouldn't the residual yeast used in bottle fermentation scavenge most or all of the oxygen dissolved in the beer?
i-a-n
Well-Known Member
Speaking of science, I've a science degree so here's my take on it. Just do what we used to do as students studying science. Ferment in fermentation vessel for a week, tap straight out of the vessel into a pint glass mix with cheap cider. Repeat about 8times a night, Bingo!
Worked for us.
Worked for us.
hotmelt
Well-Known Member
You could always minimise the head space by inflating a food grade balloon with co2.
Here's an idea.
There must be a gas that cannot permeate HDPE plastic. So if you fill a sealed HDPE vessel with that gas, then according to previous posts the Oxygen in the atmosphere will migrate into the vessel through the walls until the oxygen outside the vessel is in equilibrium with the oxygen inside the vessel.
Thus if your original gas in the vessel was at one atmosphere, by the time the oxygen has entered the vessel the pressure would be far higher as the original gas is unable to escape. Say two atmospheres.
So if you take a series of a large number of vessels and using spunding valves or sealed pistons or something you could use this difference in pressure to turn wheels, generate electricity etc.
When the vessels have been returned to one atmosphere, the oxygen can be removed, either by a reducing agent or getting kittens to breathe it or whatever and start again.
The Bribie Oxygen engine has been invented.
There must be a gas that cannot permeate HDPE plastic. So if you fill a sealed HDPE vessel with that gas, then according to previous posts the Oxygen in the atmosphere will migrate into the vessel through the walls until the oxygen outside the vessel is in equilibrium with the oxygen inside the vessel.
Thus if your original gas in the vessel was at one atmosphere, by the time the oxygen has entered the vessel the pressure would be far higher as the original gas is unable to escape. Say two atmospheres.
So if you take a series of a large number of vessels and using spunding valves or sealed pistons or something you could use this difference in pressure to turn wheels, generate electricity etc.
When the vessels have been returned to one atmosphere, the oxygen can be removed, either by a reducing agent or getting kittens to breathe it or whatever and start again.
The Bribie Oxygen engine has been invented.
TheWiggman
Haters' gonna hate
Aha! But the actual pressure will not change! Just the composition (as the oxygen gets in, other said gas will go out).
Will need to find another use for your kittens.
Ed: why has nobody commented on the spelling of the thread title?
Will need to find another use for your kittens.
Ed: why has nobody commented on the spelling of the thread title?
Feldon
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I think the thread title is strictly correct.
A fermentor is a vessel in which fermentation occurs, just as a reactor is a vessel in which a reaction (eg. nuclear) occurs.
A fermenter is something that causes fermentation (eg. yeast is a fermenter).
Six of one etc... whatever pops your airlock.
A fermentor is a vessel in which fermentation occurs, just as a reactor is a vessel in which a reaction (eg. nuclear) occurs.
A fermenter is something that causes fermentation (eg. yeast is a fermenter).
Six of one etc... whatever pops your airlock.
TheWiggman
Haters' gonna hate
Well I'll be buggered.
i-a-n
Well-Known Member
Is that strictly within the remit of this forum?TheWiggman said:
Yob
Hop to it
Hay wadda-ya-know, my stout didn't turn fungal.. Left for a week (or so) after terminal gravity,
As a refresher, single batch, 50l (ss) FV
As a refresher, single batch, 50l (ss) FV
Blind Dog
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[SIZE=medium]Oxygen is bad for fermented beverages. HDPE lets in oxygen, and lots of it. Bungs and airlocks also let in loads even if they fit snugly. And size does matter (maybe)[/SIZE]
[SIZE=medium]Last week I hadn’t given it much thought at all. Now I’m worried and looking to change my fermenters. I’ve not really had an issue with oxidisation yet, but I never want one either. [/SIZE]
[SIZE=medium]For that alone, it’s been an interesting read. So thanks to all[/SIZE]
[SIZE=medium]Last week I hadn’t given it much thought at all. Now I’m worried and looking to change my fermenters. I’ve not really had an issue with oxidisation yet, but I never want one either. [/SIZE]
[SIZE=medium]For that alone, it’s been an interesting read. So thanks to all[/SIZE]
Yob
Hop to it
If it ain't a problem you can detect, it ain't really an issue,
the beer I make doesn't last long enough to stale
the beer I make doesn't last long enough to stale
Blind Dog
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Don't talk sense when I'm trying to justify to myself the cost of upgrading to SS fermenters. It's just not fairYob said:If it ain't a problem you can detect, it ain't really an issue,
the beer I make doesn't last long enough to stale
