# Effects of Altitude on Carbonation

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#### BeerPirate

##### Active Member
Does anyone out there know if there is an effect of altitude on the carbonation of beer in bottles during conditioning. I ask because I live in Laramie, WY at 7200'. My beer is carbonating fine, I'm just curious about the logistics of this. My guess is that since the air is thinner the higher you go and yeast produces CO2 in relation to the sugars in the wort, once the bottle is sealed the yeast would produce CO2 at the same rate in similar worts regardless of altitude. So if the atmosphere is more dense at sea level then the addition of CO2 would increase pressure faster than the same volume of CO2 added to a less dense airspace in a bottle bottled at a higher elevation. Anyway, I'm just trying to play scientist. I'm happy with my carbonation results, I'm just curious what you all think about this theory.

#### tnlandsailor

##### Well-Known Member
I really thought someone would pick up this thread and run with it. Guess not. Here is my 2 cents:

If you bottle at 7200 feet and at sea level, the two bottles have correspodingly different pressures in the head space when you cap them. Namely:

11.3 PSIA at 7200 ft
14.7 PSIA at sea level

Now, 3.5 PSI difference between the two sounds like a lot, but that's not the only parameter here. The beer at altitude will have to produce a bit more CO2 to carbonate to the same level as the sea level beer, but this is a function of the volume of beer in the bottle and the volume of head space. A typical head space volume is maybe 0.5 cubic inches (in3). In contrast, for a 12 oz beer to carbonate to 2.3 volumes of C02 (typical), it must produce about 50 in3 of CO2 (trust me on the math here). That means, the head space volume is really negligible. For larger bottles, it's even more so. Even if you bottled in a complete vacuum, the amount of CO2 produced by the beer in the bottle is so much larger than the head space, it's really a non issue.

The other issue is when you drink the beer. Since you are at altitude when you open and drink the beer, it will tend to lose its carbonation faster because of the lower atmospheric pressure, so you may perceive more carbonation.

What does it all mean? It means, if you bottle and drink at the same elevation, the same amount of priming sugar will produce the same amount of CO2 and the same perceived carbonation level. Now: what happens when you bottle at elevation and take it down to sea level and vice versa? Lower levels of perceived carbonation for the bottled high and drunk low beer, and higher levels of perceived carbonation for the bottled low and drunk high beer.

Does hot water really freeze faster than cold water?

Prosit!

OP
B

#### BeerPirate

##### Active Member
Thanks, I thought more people would reply to this thread too. Good information, I knew that any differences would be negligible because my beer has been turning out fine, I just wanted to know a little of the science behind it.

#### Sasquatch

##### Well-Known Member
Local HBS gives 1 and 1/4 cups of sugar per batch, saying that at higher altitudes (I think I'm 3000 ft) you need more carbonation... I dunno how that figures, as I would have thought that with less pressure, the relative effect of the CO2 would be higher, as speculated above...

##### Well-Known Member
this is an old thread, but I have a question.

Do you think the elevation change is noticeable?

I've moved (close by to the university I attend) to Jerusalem, ~700m above see level.
I still brew at my parents' house, at ~200m .
I took beers with me here, of three different batches, and they all feel more carbonated.
My Saison was effervescent to begin with, but now its overcarbonated, and nearly gushes out of the bottle.
I might be imagining it about the other two beers, I'm not sure.

do you think this change in altitude could cause this?

could "bleeding" the bottles help here? how do I quantify this gas release?

thanks!

#### Parker36

##### Well-Known Member
Yes, the change in altitude could change the perceived carbonation level. At higher elevations, the CO2 will tend to come out of the solution at a faster rate due to lower atmospheric pressure - this is why things go flat faster at higher elevations, and also why things boil at a lower temp.

I do not, however, think that the problem with the saison is due to the change in altitude. You have only increased by 500m, which really isn't that huge of a difference. For example, I live at a little over 1600m and have drunk my homebrew as high as 3000+m and although carbonation has. Further more, I have had Coca Cola which is bottled in Dallas, TX (elevation 130m) at elevations approaching 4000m and even then they didn't explode - although they do seem overly carbonated and go flat very quickly.

#### AlchemyBrewing

##### Well-Known Member

I guess my question pertains to keg carbonation at altitude. I am at about 5600' just south of Denver. Do I need to adjust my CO2 psi or just use the same level recommended in the charts?

#### yogensha

##### Well-Known Member
I've come across this thread before and now that it's back from the dead, I decided to give it some more thought.

My conclusion: I don't think you need to make any adjustments. The regulator gauges are relative to the local atmospheric pressure (psig). So are the charts.

When you pressurize the keg to 10 psig, the beer absorbs CO2 to some point and stops and the system is equalized. When you pull a pint out of the keg, the beer is exposed to an environment with 10 psi less than where it was, so CO2 comes out of solution until the system equalizes again. That 10 psi differential is the same while absorbing or releasing CO2 regardless of the absolute atmospheric pressure, assuming of course that you didn't carbonate at one elevation and pour at another.

I think this agrees with what tnlandsailor said (nearly 5 years ago).

#### AlchemyBrewing

##### Well-Known Member
Thanks for the help. When I read his post it doesn't talk about force carbing and only the differences in priming sugar. Either way this makes sense and I will proceed.

#### Aa760

##### Well-Known Member
Just took my bottle conditioned and (well) carbonated pumpkin ale (I live and brew at sea level) up to 2700 feet today for some mountain fun. It is at about 2.7 volumes of CO2 here at sea level. It did seem more foam-y at the mild elevation at which we were. I went looking up info on this phenomenon today and found this thread. I was wondering if it was just me, but it seems that there is some science behind the effect we noticed. Just thought I would put forth some experiential evidence for those that may be looking for the same information. Bottle low, drank high = more carbonation- perceived or otherwise!