[Big Monk]

Do commercial breweries typically force carbonate their beer with non-fermentation produced CO2 (excluding bottle conditioned beers and RHGB compliant breweries)?

Almost every one I'm aware of does.

True, but keep in mind that professional breweries specify a grade of CO2 (minimum of 99.99%) that is just not available to the average or even above average homebrewer. At that purity, you are talking about < 5-10 ppm O2 impurity.

[denny]

True, but keep in mind that professional breweries specify a grade of CO2 (minimum of 99.99%) that is just not available to the average or even above average homebrewer. At that purity, you are talking about < 5-10 ppm O2 impurity.

That's a good point.  I think I'll check with some breweries to see if that's what they really use.

[BrewBama]

Does the entire  .01%, .1%, or .5% in 99.99%, 99.9%, and 99.5% pure CO2 contain pure O2?  Couldn’t it contain other gases besides O2?  If so, couldn’t the uptake of O2 be less?


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[Big Monk]

Does the entire  .01%, .1%, or .5% in 99.99%, 99.9%, and 99.5% pure CO2 contain pure O2?  Couldn’t it contain other gases besides O2?  If so, couldn’t the uptake of O2 be less?


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We didn’t use percentages. O2 impurity is listed explicitly as ppm so we didn’t have to do any guesswork. You are right though, there are other impurities that make up that percentage, but we aren’t concerned with those. We only care about the O2 in ppm for these calculations.

[Wilbur]

Does the entire  .01%, .1%, or .5% in 99.99%, 99.9%, and 99.5% pure CO2 contain pure O2?  Couldn’t it contain other gases besides O2?  If so, couldn’t the uptake of O2 be less?


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That's an interesting point, air is 78% nitrogen and 21% oxygen. How of commercial CO2 produced?

[Big Monk]

Does the entire  .01%, .1%, or .5% in 99.99%, 99.9%, and 99.5% pure CO2 contain pure O2?  Couldn’t it contain other gases besides O2?  If so, couldn’t the uptake of O2 be less?


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That's an interesting point, air is 78% nitrogen and 21% oxygen. How of commercial CO2 produced?

It’s an interesting but moot point, as all grades of CO2 99.5% or purer list O2 impurity in ppm.

[narcout]

That's a good point.  I think I'll check with some breweries to see if that's what they really use.

I'd be interested to hear about that.

[Andy Farke]

I want to kind of take what you’ve said and parse it so we can hit everything you asked/commented on.

<snip -- edited out text for brevity>

As far as the serving pressure add to the sum total, you are correct. It’s not all added up front, but again, we made some assumptions here:

1.) You are sufficiently purging your kegs. That means liquid purging the ENTIRE keg, including the entirely of the headspace (liquid coming out of the PRV). If you aren’t doing that, you are adding to the DO in the finished beer.

2.) We assumed 2.5 volumes of carbonation. Obviously anything higher increases the DO in the finished beer.

3.) Again, we assume a grade of CO2 that is of a much higher purity than most are probably using.

Ultimately we just wanted to bring to light something that may not have been on people’s radar.

Cool, thanks for the detailed response!

So at least on the cold side, it seems like homebrewers have (more or less) two options to minimize cold side aeration effectively:

1) Complete keg purging+careful closed transfer+spunding+food-grade CO2+cold storage -- slow, but the Cadillac option in terms of minimizing oxygen content at start

2) Complete keg purging+careful closed transfer+food-grade CO2+cold storage -- faster, some potential for near-term oxidation, but likely minimal if you follow this protocol precisely with high-quality CO2 and careful keg purging.

And adequate purging and good quality CO2 really are the key steps.

[Big Monk]

I want to kind of take what you’ve said and parse it so we can hit everything you asked/commented on.

<snip -- edited out text for brevity>

As far as the serving pressure add to the sum total, you are correct. It’s not all added up front, but again, we made some assumptions here:

1.) You are sufficiently purging your kegs. That means liquid purging the ENTIRE keg, including the entirely of the headspace (liquid coming out of the PRV). If you aren’t doing that, you are adding to the DO in the finished beer.

2.) We assumed 2.5 volumes of carbonation. Obviously anything higher increases the DO in the finished beer.

3.) Again, we assume a grade of CO2 that is of a much higher purity than most are probably using.

Ultimately we just wanted to bring to light something that may not have been on people’s radar.

Cool, thanks for the detailed response!

So at least on the cold side, it seems like homebrewers have (more or less) two options to minimize cold side aeration effectively:

1) Complete keg purging+careful closed transfer+spunding+food-grade CO2+cold storage -- slow, but the Cadillac option in terms of minimizing oxygen content at start

2) Complete keg purging+careful closed transfer+food-grade CO2+cold storage -- faster, some potential for near-term oxidation, but likely minimal if you follow this protocol precisely with high-quality CO2 and careful keg purging.

And adequate purging and good quality CO2 really are the key steps.

Yup. Spunding eliminates the real damaging amounts of oxygen by eliminating the need to force carbonate. Serving using bottle gas is a required evil for anyone.

The reason we found this topic in particular so important is that it affects all of us.

[majorvices]

We have been getting questions about why people should be interested in CO2 purity and what damaging effects the O2 impurities within bottled CO2 can have on the finished beers of ALL brewers.

We have been working on a blog post for some time and we finally finalized and posted a write-up on it today:

http://www.lowoxygenbrewing.com/brewing-methods/carbon-dioxide-purity/

Let's discuss it!

It's great to have a DO meter so that you can test the purity of your Co2. Unfortunately a decent one costs about $8K.... I would gladly test anyone's Co2 for them for a small fee.

[The Beerery]

We have been getting questions about why people should be interested in CO2 purity and what damaging effects the O2 impurities within bottled CO2 can have on the finished beers of ALL brewers.

We have been working on a blog post for some time and we finally finalized and posted a write-up on it today:

http://www.lowoxygenbrewing.com/brewing-methods/carbon-dioxide-purity/

Let's discuss it!

It's great to have a DO meter so that you can test the purity of your Co2. Unfortunately a decent one costs about $8K.... I would gladly test anyone's Co2 for them for a small fee.

Orbisphere?


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[Robert]

It's great to have a DO meter so that you can test the purity of your Co2. Unfortunately a decent one costs about $8K.... I would gladly test anyone's Co2 for them for a small fee.

While it is no doubt good to be AWARE of this issue, as I see it, there's simply nothing I can do about it; I have to take my CO2 as I find it.

 Am I a total outlier here in thinking that this is a bit of a non issue because, as a homebrewer, I have the luxury of drinking my beer quite fresh (kegs are nearly always gone in 2 weeks), so I can relax about what is _primarily_ a shelf life concern (as long as I'm not doing full on LO?)

[klickitat jim]

It's great to have a DO meter so that you can test the purity of your Co2. Unfortunately a decent one costs about $8K.... I would gladly test anyone's Co2 for them for a small fee.

While it is no doubt good to be AWARE of this issue, as I see it, there's simply nothing I can do about it; I have to take my CO2 as I find it.

 Am I a total outlier here in thinking that this is a bit of a non issue because, as a homebrewer, I have the luxury of drinking my beer quite fresh (kegs are nearly always gone in 2 weeks), so I can relax about what is _primarily_ a shelf life concern (as long as I'm not doing full on LO?)

I find it interesting, in that it's brewing related so therefore interesting by default. I have no doubt that it's a major issue for someone. For me it's trivial and unfixable, so in effect I would almost be better off not even knowing about it. Interesting, but...

[Big Monk]

It's great to have a DO meter so that you can test the purity of your Co2. Unfortunately a decent one costs about $8K.... I would gladly test anyone's Co2 for them for a small fee.

While it is no doubt good to be AWARE of this issue, as I see it, there's simply nothing I can do about it; I have to take my CO2 as I find it.

 Am I a total outlier here in thinking that this is a bit of a non issue because, as a homebrewer, I have the luxury of drinking my beer quite fresh (kegs are nearly always gone in 2 weeks), so I can relax about what is _primarily_ a shelf life concern (as long as I'm not doing full on LO?)

I find it interesting, in that it's brewing related so therefore interesting by default. I have no doubt that it's a major issue for someone. For me it's trivial and unfixable, so in effect I would almost be better off not even knowing about it. Interesting, but...

It’s not a matter of IF you can do something about, Spunding solves the force carbonation issue, but rather a matter of if you WANT to. That’s a choice you would have to make.

[klickitat jim]

But what about serving?