Author Topic: Equation for Bottle CO2 Volumes  (Read 1199 times)

Derek

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Equation for Bottle CO2 Volumes
« on: May 06, 2015, 04:58:26 PM »
Looking for an equation to input in excel and determine maximum CO2 limits for various bottles styles.

Ive read and been told that standard longnecks are actually rated for much higher pressure than people seem to think and being an engineer in nuclear with a working knowledge of how important conservatism and margin is, I cant help but think that standard longnecks may be a cheaper alternative for my belgian brews.

A request to Northern Brewer customer service yielded an equation similar to the Ideal Gas equation but I cant make the ends meet as their response wasnt formatted well.

Any thoughts/input?

Offline Phil_M

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Re: Equation for Bottle CO2 Volumes
« Reply #1 on: May 06, 2015, 06:05:26 PM »
I don't have much to add, but I've been wondering about the same thing. I didn't do a lot of research, but I didn't find any "real" data on bottle pressure limits. (As in tested/manufacturers spec, etc. But I didn't do a lot of looking.)

Also, I wonder at what point caps/caged corks will fail.

I don't see how an equation helps, at least not till the limits of the bottles are found.
« Last Edit: May 06, 2015, 06:32:06 PM by Phil_M »
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Offline kramerog

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Re: Equation for Bottle CO2 Volumes
« Reply #2 on: May 06, 2015, 06:51:27 PM »
When I carbonated to 3 v/v, some of the long neck bottles cracked. 

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Re: Equation for Bottle CO2 Volumes
« Reply #3 on: May 06, 2015, 06:52:35 PM »
I find it difficult to believe that this could actually be done. Or rather, that the amount of effort would ever justify it. You'd have to account for surface-to-volume ratio, glass thickness, radius of the corners, etc… And that would just be for a cylinder. No two bottles are the same shape.

I don't think there's any problem with counter-pressure filling a standard longneck to any practical pressure. They're rated to 3-4 atm and at cellar temperatures that will do >4 vol CO2. It's when you need to carbonate at room temperature that you might have issues. Even then, 45 psig is ~3.5 vol, though as you said you'd probably want to retain some safety margin.
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Derek

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Re: Equation for Bottle CO2 Volumes
« Reply #4 on: May 06, 2015, 07:09:02 PM »
The limits are known. Take for instance the Euro 16 oz. It is nominally rated for 5 Bar/70 psi (These being the generic 16 oz. bottles sold by Northern Brewer, More Beer, etc.).

The equation given to me by the agent at NB was, to the best of my knowledge, is as follows:

((Vbottle (in liters)*PkPa (rated bottle pressure))/8.314)/TKelvin*44.01*.506

This is obviously a form of the ideal gas equation PV=nRT. R= 8.314 (gas constant). 44.01 represents the molar mass of CO2.

Derek

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Re: Equation for Bottle CO2 Volumes
« Reply #5 on: May 06, 2015, 07:13:14 PM »
I find it difficult to believe that this could actually be done. Or rather, that the amount of effort would ever justify it. You'd have to account for surface-to-volume ratio, glass thickness, radius of the corners, etc… And that would just be for a cylinder. No two bottles are the same shape.

I don't think there's any problem with counter-pressure filling a standard longneck to any practical pressure. They're rated to 3-4 atm and at cellar temperatures that will do >4 vol CO2. It's when you need to carbonate at room temperature that you might have issues. Even then, 45 psig is ~3.5 vol, though as you said you'd probably want to retain some safety margin.

To your point, I would only want to get an approximation. I plan on bottling Belgians at cellar temperature for extended aging. Being that i'm curious and love equations I just want to gain some insight into the methodology.

It's really a "one and done" calculation so I could have a number I felt comfortable with for using 12 oz. bottles. I feel that they may be stronger than most people think.

Offline erockrph

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Re: Equation for Bottle CO2 Volumes
« Reply #6 on: May 06, 2015, 07:29:14 PM »
I find it difficult to believe that this could actually be done. Or rather, that the amount of effort would ever justify it. You'd have to account for surface-to-volume ratio, glass thickness, radius of the corners, etc… And that would just be for a cylinder. No two bottles are the same shape.

I don't think there's any problem with counter-pressure filling a standard longneck to any practical pressure. They're rated to 3-4 atm and at cellar temperatures that will do >4 vol CO2. It's when you need to carbonate at room temperature that you might have issues. Even then, 45 psig is ~3.5 vol, though as you said you'd probably want to retain some safety margin.

To your point, I would only want to get an approximation. I plan on bottling Belgians at cellar temperature for extended aging. Being that i'm curious and love equations I just want to gain some insight into the methodology.

It's really a "one and done" calculation so I could have a number I felt comfortable with for using 12 oz. bottles. I feel that they may be stronger than most people think.
Under ideal conditions for the initial use, you are probably right. But there will be some variations within a particular batch of bottles, plus microscopic weaknesses that will weaken over time. Feel free to take your chances, but I prefer to keep it to a max of 3 volumes for most 12oz bottles. You may get lucky for a while, but it only takes one outlier to cause some serious damage. A poorly mixed batch of priming solution or batch of beer that wasn't quite fully attenuated (or gets contaminated) now has no "wiggle room" for error if you try to push things to the limit.
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Derek

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Re: Equation for Bottle CO2 Volumes
« Reply #7 on: May 06, 2015, 07:32:53 PM »
I find it difficult to believe that this could actually be done. Or rather, that the amount of effort would ever justify it. You'd have to account for surface-to-volume ratio, glass thickness, radius of the corners, etc… And that would just be for a cylinder. No two bottles are the same shape.

I don't think there's any problem with counter-pressure filling a standard longneck to any practical pressure. They're rated to 3-4 atm and at cellar temperatures that will do >4 vol CO2. It's when you need to carbonate at room temperature that you might have issues. Even then, 45 psig is ~3.5 vol, though as you said you'd probably want to retain some safety margin.

To your point, I would only want to get an approximation. I plan on bottling Belgians at cellar temperature for extended aging. Being that i'm curious and love equations I just want to gain some insight into the methodology.

It's really a "one and done" calculation so I could have a number I felt comfortable with for using 12 oz. bottles. I feel that they may be stronger than most people think.
Under ideal conditions for the initial use, you are probably right. But there will be some variations within a particular batch of bottles, plus microscopic weaknesses that will weaken over time. Feel free to take your chances, but I prefer to keep it to a max of 3 volumes for most 12oz bottles. You may get lucky for a while, but it only takes one outlier to cause some serious damage. A poorly mixed batch of priming solution or batch of beer that wasn't quite fully attenuated (or gets contaminated) now has no "wiggle room" for error if you try to push things to the limit.

Good point. I have about 24 saved belgian bottles so i'm not worried. I can always use those for my clones and longnecks and stubbies at lower pressures for my original belgian recipes.

Ultimately, what is the purpose of carbing to volumes > 3?

Offline HoosierBrew

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Re: Equation for Bottle CO2 Volumes
« Reply #8 on: May 06, 2015, 07:35:46 PM »
I find it difficult to believe that this could actually be done. Or rather, that the amount of effort would ever justify it. You'd have to account for surface-to-volume ratio, glass thickness, radius of the corners, etc… And that would just be for a cylinder. No two bottles are the same shape.

I don't think there's any problem with counter-pressure filling a standard longneck to any practical pressure. They're rated to 3-4 atm and at cellar temperatures that will do >4 vol CO2. It's when you need to carbonate at room temperature that you might have issues. Even then, 45 psig is ~3.5 vol, though as you said you'd probably want to retain some safety margin.

To your point, I would only want to get an approximation. I plan on bottling Belgians at cellar temperature for extended aging. Being that i'm curious and love equations I just want to gain some insight into the methodology.

It's really a "one and done" calculation so I could have a number I felt comfortable with for using 12 oz. bottles. I feel that they may be stronger than most people think.
Under ideal conditions for the initial use, you are probably right. But there will be some variations within a particular batch of bottles, plus microscopic weaknesses that will weaken over time. Feel free to take your chances, but I prefer to keep it to a max of 3 volumes for most 12oz bottles. You may get lucky for a while, but it only takes one outlier to cause some serious damage. A poorly mixed batch of priming solution or batch of beer that wasn't quite fully attenuated (or gets contaminated) now has no "wiggle room" for error if you try to push things to the limit.

Good point. I have about 24 saved belgian bottles so i'm not worried. I can always use those for my clones and longnecks and stubbies at lower pressures for my original belgian recipes.

Ultimately, what is the purpose of carbing to volumes > 3?

Belgian stuff. Some of it is carbed up pretty high.
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Offline Phil_M

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Re: Equation for Bottle CO2 Volumes
« Reply #9 on: May 06, 2015, 07:36:47 PM »
The limits are known. Take for instance the Euro 16 oz. It is nominally rated for 5 Bar/70 psi (These being the generic 16 oz. bottles sold by Northern Brewer, More Beer, etc.).

The equation given to me by the agent at NB was, to the best of my knowledge, is as follows:

((Vbottle (in liters)*PkPa (rated bottle pressure))/8.314)/TKelvin*44.01*.506

This is obviously a form of the ideal gas equation PV=nRT. R= 8.314 (gas constant). 44.01 represents the molar mass of CO2.

Ah ok. Did you get that bottle info from NB? I may contact them to find the limits of the Belgian cork-finish style bottles I've got.
Corn is a fine adjunct in beer.

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Derek

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Re: Equation for Bottle CO2 Volumes
« Reply #10 on: May 06, 2015, 11:51:20 PM »
The limits are known. Take for instance the Euro 16 oz. It is nominally rated for 5 Bar/70 psi (These being the generic 16 oz. bottles sold by Northern Brewer, More Beer, etc.).

The equation given to me by the agent at NB was, to the best of my knowledge, is as follows:

((Vbottle (in liters)*PkPa (rated bottle pressure))/8.314)/TKelvin*44.01*.506

This is obviously a form of the ideal gas equation PV=nRT. R= 8.314 (gas constant). 44.01 represents the molar mass of CO2.

Ah ok. Did you get that bottle info from NB? I may contact them to find the limits of the Belgian cork-finish style bottles I've got.

Yes. That's from either my email response from NB or my LHBS website. Those Belgian bottles should be rated about the same if I'm not mistaken.

Personally I'll just end up using my saved 33 cl Belgian bottles from my Chimays, Westmalles, and Rocheforts for styles that absolutely need the higher volumes and stubbies and longnecks carbed < 3 for all others. As long as the beer carbs I don't see the point in anything higher than that unless specifically called for by style or specific clone recipe.

Offline reverseapachemaster

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Re: Equation for Bottle CO2 Volumes
« Reply #11 on: May 07, 2015, 02:27:08 PM »
Ultimately, what is the purpose of carbing to volumes > 3?

In BLAM and other texts on Belgian beer you'll see a lot of references about how high carbonation improves drinkability by giving the impression of a lighter body. I can take or leave that explanation. The real benefit, IMO, of the higher carbonation is that it enhances the presence and flavors of the esters in the beer. If you've ever been served a Belgian style beer on gravity or off a beer engine you quickly find the esters are muted and it tastes very different.
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Derek

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Re: Equation for Bottle CO2 Volumes
« Reply #12 on: May 07, 2015, 05:25:48 PM »
So by that rationale, would carbing at lower volume de-emphasize the more pronounced esters of an immature beer?

Offline Chino Brews

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Re: Equation for Bottle CO2 Volumes
« Reply #13 on: May 11, 2015, 08:40:59 PM »
One thing I'll note is that there really even such as thing as a "standard" 12-oz. amber longneck.

A couple months ago I weighed 5-6 clean, de-labeled, "standard" longnecks I had in my kitchen to answer a question on another forum, and the weight difference between the heaviest to the lightest was almost 15%. You could feel the difference in weight and glass thickness. I have to believe that their failure limits vary by at least as much, and probably more.

I don't think I'd ever shoot for more than 3.2 volumes in a longneck, because I feel that gives me an adequate safety margin in case of an in-bottle contamination.
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