How much oxygen can dissolve in wort?

[Finlandbrews]

I'm just wondering if further oxygen can dissolve in wort - after boilong-by air contact? Are the oxygen levels increasing in wort and what is the limit of oxygen that can dissolve in wort with air contact? Is the oxygen level lowest at peak of boil time? Thanks for the help.

 

[astacey1403]

I dont't know of any specific numbers as far as how much O2 that the wort can absorb, how ever I do know that at end of boil is when O2 levels are the lowest. Maybe not exactly at the end I'm sure a lot of the O2 leaves very quickly at the start of the boil. If the wort is not Aerate when cooling little O2 will get in. Do remember though yeast need O2 during fermentation witch is why introducing O2 back into the wort once it is cooled is very important.

 

[Finlandbrews]

I dont't know of any specific numbers as far as how much O2 that the wort can absorb, how ever I do know that at end of boil is when O2 levels are the lowest. Maybe not exactly at the end I'm sure a lot of the O2 leaves very quickly at the start of the boil. If the wort is not Aerate when cooling little O2 will get in. Do remember though yeast need O2 during fermentation witch is why introducing O2 back into the wort once it is cooled is very important.

Thanks for the valuable feedback! Btw I wonder if it is better to add oxygen to wort as late as possible, in other words just before pitching and how fast dissolved O2 -which is injected into wort- can escape into the head of the fermenter?

 

[astacey1403]

No worries my friend. You don't want to add any O2 until the wort has cooled. I have not had this problem my self but I have heard that O2 in hot wort can cause flavor problems. I personally hard pour my cooled wort into a fermenter and shack it up for a bit then ill pitch my yeast. Aerating the wort after pitching the yeast is ok so long as its not several hours after pitching. O2 does not negatively affect the yeast, its the alcohol that dislikes the O2 and it take a while for the yeast to actually produce any. As far as O2 leaving the aerated wort I have some idea on how this works. Think of the wort in the fermenter as one level and the air above it as a second level. Both of these levels have a capacity (not sure how much O2 can dissolve in wort so we will assume there is a capacity/limit). once level 2 has a certain volume of O2 (at capacity) no more will fall out of level 1. This is so long as you have and air lock on your fermenter. Don't quote me on this but I believe this is how it works lol. You don't see any air lock activity right after you pitch and close up the fermenter. If there was that either means there is some temp movement, enough to either cause pressure or vacuum in the fermenter, or there is gas pressure coming from something inside the fermenter (O2 leaving the fermenter)

 

[helibrewer]

Thanks for the valuable feedback! Btw I wonder if it is better to add oxygen to wort as late as possible, in other words just before pitching and how fast dissolved O2 -which is injected into wort- can escape into the head of the fermenter?

The diffusion is all based on the partial pressure of O2 in the 2 fluids (air and wort). With just exposure to air, the wort will eventually get back up to about 8ppm O2 since that is what is in atmospheric air.

For your fermenter with wort infused with O2, the opposite happens, the O2 leaves the wort into the headspace. You could slow this by flooding the headspace with O2 also.

You should Oxygenate at time of yeast pitching or very shortly there after since the O2 is needed during the initial lag phase while the yeast are biochemically very busy. The yeast complete this activity in 8-12 hours.

 

[Yooper]

If I remember correctly, it's about 12 ppm at a max of DO (dissolved oxygen) using an o2 set up with a diffusion stone.

 

[h22lude]

If I remember correctly, it's about 12 ppm at a max of DO (dissolved oxygen) using an o2 set up with a diffusion stone.

But wouldn't that mean it is impossible to over oxygenate?

 

[helibrewer]

I thought the 12 ppm max was with AIR and a diffusion stone...

 

[55x11]

But wouldn't that mean it is impossible to over oxygenate?

You can't exceed maximum solubility value, yes. It will come out as air bubbles.

Maximum oxygen that can be dissolved in water is actually 14.6ppm at freezing point, and it's about 10ppm at room temperature.


By splashing you can only get 4ppm or so. From Chris White's "Yeast":

"The wort splashing devices employed by many homebrewers will result in approximately 4 ppm, less than half the required amount. Commercial brewers using similar methods will find they get comparable results. With plenty of headspace, a strong back, and lots of vigorous shaking, a home-brewer can get levels as high as 8 ppm into the wort. This is about the maximum using air. Using an aquarium pump with a sintered stone will not result in more than 8 ppm, even with extended times. In fact, extended aeration can be detrimental to the head formation and retention. The only way to reach the recommended 10 ppm minimum is with the addition of oxygen.

Chris White "Yeast (Kindle Locations 1468-1473)"

 

[helibrewer]

With pure O2 infusion you can drive that dO2 up...Injection O2 systems easily can get to 18ppm dO2

 

[h22lude]

You can't exceed maximum solubility value, yes. It will come out as air bubbles.

Maximum oxygen that can be dissolved in water is actually 14.6ppm at freezing point, and it's about 10ppm at room temperature.


By splashing you can only get 4ppm or so. From Chris White's "Yeast":

"The wort splashing devices employed by many homebrewers will result in approximately 4 ppm, less than half the required amount. Commercial brewers using similar methods will find they get comparable results. With plenty of headspace, a strong back, and lots of vigorous shaking, a home-brewer can get levels as high as 8 ppm into the wort. This is about the maximum using air. Using an aquarium pump with a sintered stone will not result in more than 8 ppm, even with extended times. In fact, extended aeration can be detrimental to the head formation and retention. The only way to reach the recommended 10 ppm minimum is with the addition of oxygen.

Chris White "Yeast (Kindle Locations 1468-1473)"

This chart from Wyeast is showing 0-26ppm with pure O2 and 8ppm from spashing.

https://www.wyeastlab.com/hb_oxygenation.cfm


If the max DO is 10ppm, there would be no talk about over oxygenating at all. We would all use pure O2 with a diffusion stone with the reg wide open for 60 seconds and not worry about anything.

 

[55x11]

This chart from Wyeast is showing 0-26ppm with pure O2 and 8ppm from spashing.

https://www.wyeastlab.com/hb_oxygenation.cfm


If the max DO is 10ppm, there would be no talk about over oxygenating at all. We would all use pure O2 with a diffusion stone with the reg wide open for 60 seconds and not worry about anything.

maximum oxygen you can ever get in equilibrium (also in distilled water) is 10ppm at room temp. and 14.6 ppm at 0degC.

You can always exceed the max by taking the system *out* of equilibrium but it will correct itself fairly quickly - within 10min, maybe half an hour. If you seal the container, you can go very, very high. Sky is the limit. The question doesn't make much sense if we are talking about out-of-equilibrium. Besides, OP is talking about boiling wort (where oxygen content is close to zero), leaving it in contact with air will eventually get to as high as 14.6ppm but that's the limit.

Just like opening a bottle of beer, CO2 now is out of equilibrium with its environment and the beer goes flat over time. You can force much more into the beer if it's sealed or out of equilibrium. But you can't have a drink that is open for hours that has been oversaturated with CO2.

 

[Novims]

V

 

[h22lude]

maximum oxygen you can ever get in equilibrium (also in distilled water) is 10ppm at room temp. and 14.6 ppm at 0degC.

You can always exceed the max by taking the system *out* of equilibrium but it will correct itself fairly quickly - within 10min, maybe half an hour. If you seal the container, you can go very, very high. Sky is the limit. The question doesn't make much sense if we are talking about out-of-equilibrium. Besides, OP is talking about boiling wort (where oxygen content is close to zero), leaving it in contact with air will eventually get to as high as 14.6ppm but that's the limit.

Just like opening a bottle of beer, CO2 now is out of equilibrium with its environment and the beer goes flat over time. You can force much more into the beer if it's sealed or out of equilibrium. But you can't have a drink that is open for hours that has been oversaturated with CO2.

Which brings me back to my original question, if 10ppm is the max when in equilibrium, why do we talk about over oxygenating? Would we just be able to turn the reg all the way open and let it go for a few minutes without caring about over oxygenating?

I'm not saying anyone is wrong, just trying to understand the concept.

 

[Finlandbrews]

This chart from Wyeast is showing 0-26ppm with pure O2 and 8ppm from spashing.

https://www.wyeastlab.com/hb_oxygenation.cfm


If the max DO is 10ppm, there would be no talk about over oxygenating at all. We would all use pure O2 with a diffusion stone with the reg wide open for 60 seconds and not worry about anything.

I'm very suspicious about wyeyeast saying splashing gets you to 8ppm oxygen! Reason for this includes Chris white saying you'll never get above 3-4 ppm with splashing and many people saying that one of their best technique for improving their beer was to use pure oxygenation - in order to reach 8-10 ppm- as recommended by most if not all experts to this day.

In my initial post I'm actually more interested about the speed and the process under which oxygen dissolves back into the wort (after the boil) with air contact but also how fast it can get out of the wort if for example we oxygenate the wort to 10 ppm while the wort is in contact with air. The reason for me asking this is to understand better how oxygen mixes in the wort and disappears from the wort.

There is no point for someone to inject pure oxygen for 45 seconds and leave the wort in contact with air 10 mins before pitching because if I understood most of the oxygen would have gone out already.

If I understand, the amount of oxygen in the wort is based on the amount of oxygen in the air so that if you have a similar wort at sea level or at the Himalayan level you will have much less oxygen while in the mountains...I do not know how to calculate that, could be interesting for the sake of understanding better wort oxygenation.

Also what is interesting to me is if wort composition can affect the speed and "amount" of oxygen that will dissolve into the wort?

 

[Finlandbrews]

The diffusion is all based on the partial pressure of O2 in the 2 fluids (air and wort). With just exposure to air, the wort will eventually get back up to about 8ppm O2 since that is what is in atmospheric air.

I am very confused that many professionals (Chris white from white labs for example and pro homebrewers) recommend to inject pure oxygen in order for the wort to reach 8 ppm of oxygen if the simple contact of air will make a wort with 8 ppm of oxygen. I am wondering therefore if all experts are wrong and if they should should instead say "the use of pure oxygen injection into wort can help as a tool against contamination by not letting your wort be in contact with air after boil but still giving oxygen to your wort".

Maybe pure oxygen injection is also much more important in breweries where huge conical fermenter would take much more time to get oxygen dissolved as there is much more liquid in very tall cylinders...

 

[Singletrack]

From a practical standpoint, oxygenate to 10 ppm and pitch. No worries about losing the DO. Wort can hold 10 ppm in equilibrium with air, so you are not going to lose much of it. There are a number of "Well actually..." caveats to this statement, of course, such as wort vs. distilled water, sea level vs. mountains, temperature, etc.


Also, from a practical standpoint, it takes "too long" to aerate your wort by just waiting for equilibrium with air. Depends on exposed surface area, etc, but too long. At a minimum, you need to do some splashing.


Probably doesn't answer your questions, I realize.

 

[h22lude]

I'm very suspicious about wyeyeast saying splashing gets you to 8ppm oxygen! Reason for this includes Chris white saying you'll never get above 3-4 ppm with splashing and many people saying that one of their best technique for improving their beer was to use pure oxygenation - in order to reach 8-10 ppm- as recommended by most if not all experts to this day.

In my initial post I'm actually more interested about the speed and the process under which oxygen dissolves back into the wort (after the boil) with air contact but also how fast it can get out of the wort if for example we oxygenate the wort to 10 ppm while the wort is in contact with air. The reason for me asking this is to understand better how oxygen mixes in the wort and disappears from the wort.

There is no point for someone to inject pure oxygen for 45 seconds and leave the wort in contact with air 10 mins before pitching because if I understood most of the oxygen would have gone out already.

If I understand, the amount of oxygen in the wort is based on the amount of oxygen in the air so that if you have a similar wort at sea level or at the Himalayan level you will have much less oxygen while in the mountains...I do not know how to calculate that, could be interesting for the sake of understanding better wort oxygenation.

Also what is interesting to me is if wort composition can affect the speed and "amount" of oxygen that will dissolve into the wort?

From a post above that quoted Chris white, he said home brewers can get 8ppm by shaking. Just need to shake vigorously but it is possible. Chris white and wyeast are in line with each other.

 

[Finlandbrews]

From a practical standpoint, oxygenate to 10 ppm and pitch. No worries about losing the DO. Wort can hold 10 ppm in equilibrium with air, so you are not going to lose much of it. There are a number of "Well actually..." caveats to this statement, of course, such as wort vs. distilled water, sea level vs. mountains, temperature, etc.


Also, from a practical standpoint, it takes "too long" to aerate your wort by just waiting for equilibrium with air. Depends on exposed surface area, etc, but too long. At a minimum, you need to do some splashing.


Probably doesn't answer your questions, I realize.

Thanks!!! It does answer to a good extent to my questions. Maybe injecting vs splashing is more used for practical reasons then such as if using glass carboy, stainless conical fermenters, or if too big volumes of wort, and so on... Even if I understood it is possible to use a whirlpool and aeration device to attach to a screwdriver without having to splash or shake.

 

[55x11]

Which brings me back to my original question, if 10ppm is the max when in equilibrium, why do we talk about over oxygenating? Would we just be able to turn the reg all the way open and let it go for a few minutes without caring about over oxygenating?

I'm not saying anyone is wrong, just trying to understand the concept.

Good question. I heard those fears before and I have been wondering the same thing.

Ok, so let me just say that "over-oxygenation" is a bit of a boogey man. It may happen on occasion but its very hard to achieve in my opinion and under-oxygenation is much more common.

It's a little like recent fears of "over-hydration" during marathon because that one woman who died during Boston Marathon from drinking so much water her electrolytes got diluted and now everyone is paranoid about drinking too much water, while basically almost ALL athletes are always severely under-hydrated during endurance events.

I feel that over-oxygenation is sort like of like over-dosing on vitamin C. Yes, it could happen in theory (and maybe occasionally in practice) but you must do it on industrial scale and be extremely careless about it.

My personal feeling (not substantiated by any facts) is that some people who work in breweries, may have left a tank of oxygen open into the wort and went to check email and came back an hour later to turn it off - and noticed yeast was laggy afterwards, and hence the "over-oxygenation" fears.

Even if you use pure oxygen tanks on home-brew scale, I would argue it's somewhat difficult to over-oxygenate just because you leave your tank open for 60 seconds instead of 30 seconds. Your small batch will out-gas much faster and your tank will probably run out of oxygen before over-saturating the beer to such an extent that it takes hours to get it back to equilibrium.

If you run a giant oxygen tank for an hour or two, and then have a much larger surface-to-volume ratio for outgassing your multi-barrel batch, that's a whole different story.


In summary - I think 30-60 seconds of open O2 tank pressure won't "over-oxygenate" your cooled wort to an extent that it will affect your fermentation process in any significant way, that's my belief, even though I only have anecdotal evidence to support this. I believe you need to scale to industrial size and go for order of magnitude more (longer exposure/bigger dose) in oxygen to get to the level that is noticeably detrimental to the yeast growth.

 

[Finlandbrews]

To follow on the topic why don't we advise to oxygenate the wort after pitching?

 

[h22lude]

Good question. I heard those fears before and I have been wondering the same thing.

Ok, so let me just say that "over-oxygenation" is a bit of a boogey man. It may happen on occasion but its very hard to achieve in my opinion and under-oxygenation is much more common.

It's a little like recent fears of "over-hydration" during marathon because that one woman who died during Boston Marathon from drinking so much water her electrolytes got diluted and now everyone is paranoid about drinking too much water, while basically almost ALL athletes are always severely under-hydrated during endurance events.

I feel that over-oxygenation is sort like of like over-dosing on vitamin C. Yes, it could happen in theory (and maybe occasionally in practice) but you must do it on industrial scale and be extremely careless about it.

My personal feeling (not substantiated by any facts) is that some people who work in breweries, may have left a tank of oxygen open into the wort and went to check email and came back an hour later to turn it off - and noticed yeast was laggy afterwards, and hence the "over-oxygenation" fears.

Even if you use pure oxygen tanks on home-brew scale, I would argue it's somewhat difficult to over-oxygenate just because you leave your tank open for 60 seconds instead of 30 seconds. Your small batch will out-gas much faster and your tank will probably run out of oxygen before over-saturating the beer to such an extent that it takes hours to get it back to equilibrium.

If you run a giant oxygen tank for an hour or two, and then have a much larger surface-to-volume ratio for outgassing your multi-barrel batch, that's a whole different story.


In summary - I think 30-60 seconds of open O2 tank pressure won't "over-oxygenate" your cooled wort to an extent that it will affect your fermentation process in any significant way, that's my belief, even though I only have anecdotal evidence to support this. I believe you need to scale to industrial size and go for order of magnitude more (longer exposure/bigger dose) in oxygen to get to the level that is noticeably detrimental to the yeast growth.

This would be an awesome test because I do think this is something like HSA. Some think it exists while others don't with no real hard evidence to support either way 100%.

To follow on the topic why don't we advise to oxygenate the wort after pitching?

It is a good idea to add O2 12 to 24 hours after pitching for bigger beers. I actually think I read on a yeast website (I believe it was Danstar) that they say it is ok to add O2 12 hours after pitching.