Co2 purity

[Qhrumphf]

Some breweries target certain amount of max allowable oxygen in their packaged beer, but that doesn't answer my question (which was rhetorical). There is no way to measure when a beer is oxidized. There is no agreed-upon correlation between the amount of oxygen in a packaged beer that will make it taste bad.

But that's the broader subject of oxidation.

To rewind to the original thread: Do you guys honestly believe using bottled co2 ruins your beer?

There's three levels to answer this.

Has an oxidative reaction occured that has formed trans-2-nonenal (example oxidative compound associated with paperiness)? If so, regardless of level, that is oxidation.

Then comes "can you taste it". Which is arguably what matters most. That can be split into an individual person's threshold for the given compound, which can be directly measured. It can also be viewed in terms of average threshold. Everyone is different and could have an individual threshold below or above that average threshold. It gets messy but it can be measured and is not subjective.

Then comes, if you can perceive it, is it detrimental. This is ultimately subjective. But still has its validity. The consensus/prevailing opinion may say "this compound is good or bad above xyz threshold", and you are free to see it differently.

 

[Bilsch]

Some breweries target certain amount of max allowable oxygen in their packaged beer, but that doesn't answer my question (which was rhetorical). There is no way to measure when a beer is oxidized. There is no agreed-upon correlation between the amount of oxygen in a packaged beer that will make it taste bad.

But that's the broader subject of oxidation.

To rewind to the original thread: Do you guys honestly believe using bottled co2 ruins your beer?

how about these..

https://tapintohach.wordpress.com/category/co2-in-beer-2/

https://www.themodernbrewhouse.com/carbon-dioxide-purity/

 

[moreb33rplz]

There's three levels to answer this.

Has an oxidative reaction occured that has formed trans-2-nonenal (example oxidative compound associated with paperiness)? If so, regardless of level, that is oxidation.

Then comes "can you taste it". Which is arguably what matters most. That can be split into an individual person's threshold for the given compound, which can be directly measured. It can also be viewed in terms of average threshold. Everyone is different and could have an individual threshold below or above that average threshold. It gets messy but it can be measured and is not subjective.

Then comes, if you can perceive it, is it detrimental. This is ultimately subjective. But still has its validity. The consensus/prevailing opinion may say "this compound is good or bad above xyz threshold", and you are free to see it differently.

I think we actually agree completely - at least with all the stuff you wrote there.

Would I rather have no oxygen in my co2 bottle? Yeah. Do I think myself, you, or a beer judge will reliably (or ever) tell a difference between two identical beers, one carbed or pushed with .0001% purer co2? Nope.

But, that's just my opinion.

 

[Qhrumphf]

I invite you to do a little googling on the available grades of CO2 and reading for yourself what the specs are. I have no idea how the other member got PPB levels as that’s not even mentioned on supplier sites. Maybe his stock was from ferment captured gas, maybe a mistake in measurement.. I have no idea.

Using an Anton Paar CBox QC. There's some element of doubt as its kind of off-label but common usage and there's mixed stories from manufacturer as to the efficacy of gas testing as opposed to liquid testing. It's calibrated by gas (high purity nitrogen), not liquid.

But as I've said before, I have ROUTINELY watched levels in transferred beer (which is the on-label usage) drop below normal transfer pickup levels with application of CO2 via carb stone (gas stripping) using bulk supply (which we've measured to 5-8ppb) and rise using bottled CO2. If the supply were in the ppm range instead of ppb, I'd expect it to rise (or rise further), not fall. It gives me some confidence that even if those gas readings aren't 100% accurate they're close to it.

Maybe we're getting fermentation capture? I don't know. I'm using standard procedure on both ends. Perhaps a previous poster was right and most CO2 is purer than regulation and the COA is is just a maximum level?

 

[bracconiere]

which we've measured to 5-8ppb

there it is again, now i'm really confused!

@Qhrumphf can you post a link to the meter you use, so i can figure this out? being i'm just looking, price is of no object!

 

[Qhrumphf]

https://www.anton-paar.com/us-en/products/details/combined-co2-and-o2-meter-cboxqctm-at-line/

 

[bracconiere]

so my math on incorrect molar weights, that either 2.5 grams in my 1.2oz's of co2 from the tank or some miniscule 0.00004 grams or something?

 

[Qhrumphf]

According to the specs even at levels up to 4ppm its accuracy is +/- 20ppb with 0.1ppb resolution.

 

[Qhrumphf]

@Qhrumphf i appreciate you posting the link for that thing, if nothing else...looking at cool stuff, you know you can't afford. because you have to formally ask how much it costs is fun! lol

(and my other idea of an inluine co2 scrubber i think is still good! people like @day_trippr with his EVA barrier would love it! )

Yeah I could never dream of affording one on my own and am lucky to have one at the job. Even a lot of breweries can't afford it. Costs more than my damned car. I've got a laundry list of things I want to check with it. Example: a friend tries to use positive pressure to the headspace to keep O2 out of a keg while adding gelatin. Given how large a cornie keg is compared to the surface area and headspace I'm not convinced it's effective. I was gonna experiment. I just never have the time.

 

[Vale71]

edit #2: vale, if you meant the it's supposed to be ppm the whole time, then that changes the whole thread!

Yep, it's ppm. Ppb is the unit you'll (hopefully) use to measure TPO or DO in your beer. Ppb kept being used where ppm should have been used and it became a persistent typo.
Qhrumphf's instrument is not meant for measurements in the gas phase and much like an immersion DO meter will give much lower measured values if you try to measure O2 in a gas mixture. On the other hand the measurements in the beer that's being carbonated do make sense as it would be very hard to get 100% of the O2 to dissolve in the beer with its solubility being orders of magnitude lower than CO2, which means that we would expect measurement in the 50-100 ppb range in the beer. If carbing in a closed vessel the remaining O2 will however end up in the headspace and still contribute to TPO.

 

[bracconiere]

Yep, it's ppm.

well i'm still confused....but on a serious note, would a O2 absorber like my link help inline on a co2 line? if people are that worried?


edit: and if it's made for testing liquid co2, i'm going to guess we're talking about a BIG tank of co2!

 

[Vale71]

Apologies if I contributed further to your confusion. The instrument is meant to measure dissolved O2. It's basically a very accurate optical DO meter. Even though it does not require immersion in the liquid because of its optical sensor that does not mean it will give meaningful readings if trying to measure O2 in a gas mixture.

 

[Vale71]

To accurately measure residual O2 in CO2 you'd need something like this. I'm pretty sure it will be horrendously expensive. And it does not even detect below 5 ppm!

https://www.mt.com/be/en/home/produ...sensor/oxygen-sensor-inpro-6950iG-12-120.html

 

[bracconiere]

It's basically a very accurate optical DO meter.

so like even if i could afford it, i'd have to turn my co2 tank upside down, and run the liquid co2 through some sorta clear tube that handle 750-1000 psi? lol

i'm glad this was the first post on a new page....i forgot this was "Brew Scienece" and not drunken rambling!


but i actually am trying to wrap my head around this though....so in an avg welding shop swap, out of the 1.2oz's i burst carb with how many grams are O2 on the norm?

 

[Vale71]

so like even if i could afford it, i'd have to turn my co2 tank upside down, and run the liquid co2 through some sorta clear tube that handle 750-1000 psi? lol

i'm glad this was the first post on a new page....i forgot this was "Brew Scienece" and not drunken rambling!


but i actually am trying to wrap my head around this though....so in an avg welding shop swap, out of the 1.2oz's i burst carb with how many grams are O2 on the norm?

Besides ruining your sensor it still wouldn't work. The instrument's response is calibrated for O2 in a water solution, not liquid O2. Dissolved oxygen is still a gas, liquid oxygen is actually a liquid. BTW residual oxygen in your CO2 canister is also still a gas as pressure and temperature would not allow it to actually change phase to liquid. Crazy stuff, huh?

 

[bracconiere]

BTW residual oxygen in your CO2 canister is also still a gas as pressure and temperature would not allow it to actually change phase to liquid.

so all a person would need is a tank with some sorta dip tube in the tank?


honestly, now i'm worried i'm wasting your time....so what @Qhrumphf showed me just measures, BOTH co2, AND O2 in water?

 

[eric19312]

Yeah I could never dream of affording one on my own and am lucky to have one at the job. Even a lot of breweries can't afford it. Costs more than my damned car. I've got a laundry list of things I want to check with it. Example: a friend tries to use positive pressure to the headspace to keep O2 out of a keg while adding gelatin. Given how large a cornie keg is compared to the surface area and headspace I'm not convinced it's effective. I was gonna experiment. I just never have the time.

Please do share the results of whatever experiments you manage to do! I'd love to see some of the various keg purging and dry hopping methods compared.

 

[Vale71]

If only it were that simple we would all be able to purchase 100.00000% pure CO2 at affordable prices. Unfortunately gases have a nasty tendency to diffuse and they will do so even in liquid CO2 so with the liquid you'd still pick up a significant O2 contamination.

 

[bracconiere]

i just re-read the product description on that thing, so it's for testing finish beer, to make sure it's properly carbed, and not oxidized.....or if carbing by wiehgt like i do, a very scientific way to figure how much more co2 you need to pump into it.


and yeah i hear super critical co2 is a GREAT solvent!

 

[Bilsch]

well i'm still confused....but on a serious note, would a O2 absorber like my link help inline on a co2 line? if people are that worried?

Not very well outside of a lab setting. These things don’t have much capacity so if you make a small mistake during installation and expose it to air...

Conversely a 50lb bottle of instrument or laser grade CO2 costs less then one of these absorbers you posted about. Also note that absorber needs to be supplied with gas with less than 10ppm O2.

 

[Qhrumphf]

Finished beer to monitor O2 pickup and potential for future oxidation. But yes.

Purge verification process and thresholds I use (and way I measured the tank) are pretty standard in the industry. And like I said, mixed stories from Anton Paar. Especially since zeroing out the O2 (calibration) value is done with super high purity nitrogen gas and not liquid (though daily verifications done pushing distilled water with less high grade nitrogen). I've never done it myself but I know we have to use a higher purity than the standard nitro tanks we have. But seems odd it could be calibrated with gas phase but not measured with it. I'm not an engineer, so what do I know.

Perhaps what I should take away is that the numbers it spits out for gas values are useful and repeatable ones, but not face value ones. Similar to fermentation refractometer readings being useful for telling if fermentation is over but can't be taken at face value for gravity. That seems reasonable enough.

Where I'm confused now is the discrepancy between my bulk supply and bottle supply then. To my knowledge they are same grade and definitely same supplier. Does that discrepancy both in measured value and behavior with dissolved oxygen levels in the beer tell me that there is indeed a purity difference? Or is something else going on? Process stays the same, just a little smaller scale.

 

[Ogilthorpe2]

So the moral of the story is to carb my kegs naturally and then only dispense with bottled CO2?

 

[day_trippr]

That's pretty much what they're trying to hammer into us plebs. The math makes it hard to argue with.
I just wish I had some of those 6.5 gallon kegs for that, because I hate ending up with less than a full five gallons x2 kegs after all the effort to brew a batch.
I can't drink empty space in a keg

Cheers!

 

[Qhrumphf]

I love the brewing science section. I almost always learn something. Usually that my observations are valid but my shop-floor-science explanation for them is sh!te.

 

[balrog]

I just like fermentation keg purge to save on how often i have to refill the 20# CO2 tank

That's the pecuniary science of thrift.

 

[day_trippr]

Indeed.



Cheers! (If I could just carbonate beer with that gas! )

 

[Bilsch]

Speaking of CO2.. I wonder if it will become hard to come by in the next few months due to vaccine shipping? If so, great time to learn about spunding.

 

[day_trippr]

In 2020 there has already been an ongoing CO2 supply chain issue due to C19 depressing the ethanol markets and the production thereof.
I presume the production of dry ice uses CO2 as feedstock, and clearly there are priorities in life...

Cheers?

 

[Vale71]

But seems odd it could be calibrated with gas phase but not measured with it. I'm not an engineer, so what do I know.

That tells us that the sensor's zero point is the same but the gradient is different for dissolved O2 and free O2. Same thing happens with polarimetric DO sensors. If you try to measure O2 in the headspace with them you get very low readings but the reality is very different.

 

[Vale71]

In 2020 there has already been an ongoing CO2 supply chain issue due to C19 depressing the ethanol markets and the production thereof.
I presume the production of dry ice uses CO2 as feedstock, and clearly there are priorities in life...

Cheers?

Hopefully they can use much more "dirty" (and cheap) CO2 sources for dry ice production.