# Volumes of CO2

### Help Support Homebrew Talk:

#### farmbrewernw

##### Well-Known Member
Can someone explain to me what volumes of CO2 means? I know how to carbonate a beer right I just want to know what the volume means, is it part's per million or a percentage of the liquid, or ????

OP

#### farmbrewernw

##### Well-Known Member
I did listen to that podcast I may have been slightly drunk when I did so I don't think I got that part.

#### Got Trub?

##### Well-Known Member
1 volume is 1 liter of CO2 at 1 atmosphere in 1 liter of fluid (beer). You can substitute gal for liter.

GT

#### ArcaneXor

##### Well-Known Member
Listen to this brew strong episode. It's all about carbonation, and they explain it very well.
The same one where they claim CO2 makes up 10% of the atmosphere? Beachfront villa in the shadow of the Transantarctic Mountains (erm, Islands), here I come!

(Sorry, I had to. Not one of JZs and JPs finer moments, though they do a great job when it comes to brewing!)

OP

#### farmbrewernw

##### Well-Known Member
1 volume is 1 liter of CO2 at 1 atmosphere in 1 liter of fluid (beer). You can substitute gal for liter.

GT
That's what I was looking for, thanks.

#### RushN24

##### Well-Known Member
So I know there are tools out there to calculate volumes of CO2 in beer but does anybody have the manual calculation? I like to know how these things work myself.

Also I've seen suggested volumes for different styles of beer go pretty high, over 5 volumes, does anybody know what volume it would take to get a bottle bomb? How much pressure can a typical brown long neck hold before breaking?

#### Sedge

##### Well-Known Member
Carbonation calculations and tables are based on Henry's Law

http://en.wikipedia.org/wiki/Henry's_law

You could also use the ideal gas law equations if you're concerned about volumes in a specific vessel size.

#### netjunk1e

##### Well-Known Member
Adding on to ideal gas law:

there are 22.4 liters in one mole of gas, so a beer carbonated to 2 volumes of co2, will have about 0.0892 moles of gas per liter, that makes 1.688 moles of gas in 5 gallons at 2 volumes. That is equal to about 0.163 pounds of CO2.

#### shortyjacobs

##### Well-Known Member
1 volume is 1 liter of CO2 at 1 atmosphere in 1 liter of fluid (beer). You can substitute gal for liter.

GT
Close.

1 volume is 1 liter of CO2 at 20°C at 1 atmosphere in 1 liter of beer.

(OP, this also means 1 volume is 5 gallons of CO2 at 20°C at 1 atm in 5 gallons of beer)

#### ArtVandelay

##### Well-Known Member
When referring to volumes of CO2 per style like 2.5, is this referring to volumes of CO2 that would dissolve at serving temperature or volumes at 20C? I've been assuming serving temp but I've never been quite sure.

#### mosquitocontrol

##### Well-Known Member
Volumes of co2 is the carbonation level how much is actually dissolved at equilibrium. To find the serving pressure you need to use the desired volume and the serving temperature inconjunction with the carbonation chart.

#### netjunk1e

##### Well-Known Member
when you have 2.5 volumes of co2 in beer, it is not temp dependent. 20 deg C refers to a standard condition at which everything is calculated, because the volume of a gas changes with temperature.

The different pressures to obtain the volume of co2 is based of Henry's law, as Henry's constant is dependent on temperature.

#### shortyjacobs

##### Well-Known Member
When referring to volumes of CO2 per style like 2.5, is this referring to volumes of CO2 that would dissolve at serving temperature or volumes at 20C? I've been assuming serving temp but I've never been quite sure.
2.4 volumes of C02 in a 5 gallon keg means:

Take 2.4*5=12 gallons of CO2, at 1 atm and 20 deg C. Compress it, and force it into your beer. You now have 2.4 volumes of CO2 in your beer, regardless of beer temp.

#### ArtVandelay

##### Well-Known Member
Thanks guys. And sorry for hijacking the thread, I feel a little slow tonight. Although volumes of CO2 is not temperature dependent, carbonation level is. If you have a beer served at 30 or a beer served at 50 F and both are 2.5 L of CO2, carbonation level will be different (more carbonation being in the 30F beer). Therefore priming sugar should be calculated to hit the desired carbonation at serving temp. Is this correct?

Ok edit: Regardless of what I'm saying, in beersmith, should I calculate priming sugar for a given volume of CO2 based on serving temp or equilibrium?

#### jsweet

##### Well-Known Member
Also I've seen suggested volumes for different styles of beer go pretty high, over 5 volumes, does anybody know what volume it would take to get a bottle bomb? How much pressure can a typical brown long neck hold before breaking?
Sorry to resurrect an incredibly old thread, but I had the same question and I'm having trouble finding info on this.

What I would find to be an incredibly useful resources would be a table of carbonation volumes and possible things that could go wrong. e.g. something like this (and I am just making these numbers up, I have no frikkin' idea):

Volumes......Possible Consequences
<2.0...........Flat/under-carbed beer
3.5.............Gushing when opened at room temperature
4.5.............Gushing when opened at fridge temperature
>5.5...........Significant bottle bomb risk

To reiterate, I am NOT claiming those numbers, I just pulled that straight out of my ass, with no personal experience whatsoever with undercarbed or gushing beer, or bottle bombs myself. This is just an example of the kind of chart I'd like to see if that sort of information is available.

I just bottled an IPA a few days ago and what with the dry hopping and my stupid auto-siphon being broken, I got significantly less beer out than I had anticipated when I added the corn sugar to the bottling bucket, and even though I was shooting for around 2.5-ish volumes, I'm going to have more like 3.2 volumes. Looks like that is no big deal, since many styles call for that much carbonation, but I was looking for a nice easy reference and couldn't find one.

Any thoughts?

#### Heavyfoot

##### Well-Known Member
shortyjacobs said:
Close.

1 volume is 1 liter of CO2 at 20°C at 1 atmosphere in 1 liter of beer.

(OP, this also means 1 volume is 5 gallons of CO2 at 20°C at 1 atm in 5 gallons of beer)
Does anyone know how many volumes of co2 would exist in water under no pressure? Would it be 1 volume at 20 C?

#### Heavyfoot

##### Well-Known Member
Sorry, technically I meant under atmospheric pressure, not no pressure.

#### Heavyfoot

##### Well-Known Member
Heavyfoot said:
Does anyone know how many volumes of co2 would exist in water under no pressure? Would it be 1 volume at 20 C?
Anyone?

#### zachattack

##### Well-Known Member
Henry's law states that the concentration of a gas dissolved in a liquid is directly proportional to the pressure of gas above the liquid.

If you have water exposed to an atmosphere, once everything equilibrates, the CO2 concentration in the water is Henry's constant (which is different for each gas/liquid combo and highly dependent on temperature) multiplied by the pressure of CO2 in the atmosphere.

If you're talking about Earth's atmosphere, that would be something like 0.04% CO2. So the amount that would dissolve in water is 0.0004 atm * .035 mol CO2/kg*atm (henry's law constant at 20 degrees C, I got this from here) = .000014 mol CO2/kg water. At 20 deg C ideal volume is 24.5 L/mol, so that's 0.000343 liters CO2 per liter of water (or volumes of CO2)

So not a lot.

If you have an atmosphere of pure CO2 (the case in a well-sealed carboy under ambient pressure after primary fermentation), and use this same formula, you'd have 0.8575 volumes. This is the CO2 present in the beer before you even add priming sugar, and that's why the fermentation temperature is important when calculating how much priming sugar to add.

I love this stuff, but then again I'm a chemical engineer :rockin:

#### Heavyfoot

##### Well-Known Member
That's exactly the info I was hoping for. Thanks!!

#### shortyjacobs

##### Well-Known Member
zachattack said:
Henry's law states that the concentration of a gas dissolved in a liquid is directly proportional to the pressure of gas above the liquid.

If you have water exposed to an atmosphere, once everything equilibrates, the CO2 concentration in the water is Henry's constant (which is different for each gas/liquid combo and highly dependent on temperature) multiplied by the pressure of CO2 in the atmosphere.

If you're talking about Earth's atmosphere, that would be something like 0.04% CO2. So the amount that would dissolve in water is 0.0004 atm * .035 mol CO2/kg*atm (henry's law constant at 20 degrees C, I got this from here) = .000014 mol CO2/kg water. At 20 deg C ideal volume is 24.5 L/mol, so that's 0.000343 liters CO2 per liter of water (or volumes of CO2)

So not a lot.

If you have an atmosphere of pure CO2 (the case in a well-sealed carboy under ambient pressure after primary fermentation), and use this same formula, you'd have 0.8575 volumes. This is the CO2 present in the beer before you even add priming sugar, and that's why the fermentation temperature is important when calculating how much priming sugar to add.

I love this stuff, but then again I'm a chemical engineer :rockin:
Well put :mug;

#### texaslou

##### Member
Old Thread I know, but it comes up on Google and helped me figure some stuff out. I did the math and turned into a pretty simple formula for force carbonation. The first premise is that your beer is already carbonated to .857 volumes because it was fermented in a sealed container with an air lock at 1 atm at 20 C. If your fermentation was done at a different temp, then you will have a different number of volumes with colder temps having more CO2 dissolved.

So, to increase your carbonation to a higher number (like 2.4 volumes) and you want to know how much CO2 to add, first take your goal volumes and subtract .857. Now I calculated the weight of CO2 per gallon at 20C and 1 atm to be 7 grams.

(goal volumes - .857 volumes) x (7 grams CO2/gallon) x (gallons of beer) = grams of CO2 to add to beer.

So, first transfer your beer to your keg and purge the room air using CO2. Then pressurize to desired force carbonation psi (higher psi gets you there faster), then weigh your CO2 bottle. When the CO2 bottle weight drops by the desired amount, your beer will be at the carbonation you want. Then lower your CO2 pressure in the keg to the value needed to maintain it at the desired volumes based on the temp/volumes tables available.