Kegs - from sea level to 7,000 ft

Has anyone ever carbonated a keg at sea level and then brought it up in elevation and had foaming issues? We have a keg that was filled and carbed in Texas, then brought it up to 7,400 ft in Colorado.

There may be other issues with my kegerator but I'm wondering if that is part I the issue.

Which would make me wonder about these balanced tap lines programs not accounting for elevation in their computation. Perhaps it only comes into play if the keg is moved?

VegasBrew1 is on the right track with regards to moving the keg.

From http://www.engineeringtoolbox.com/air-altitude-pressure-d_462.html, atmospheric pressure at sea level is 14.7 psi, at 7000 ft elevation it is 11.3 psi.

If you carbonate to 10 psig (psi gauge) at sea level, the absolute pressure is 24.7 psia. At 7000 ft, the gauge pressure would be 24.7 - 11.3, or 13.4 psig. That's quite a change in the relative pressure, even though it hasn't changed the volumes of CO2 in the beer.

Yep! That was my theory. Now to de-carbonate this beer...

Shouldn't be any issue for the beer. The volumes of CO2 in the beer and the partial Co2 pressure in the headspace will be unchanged.

No need to decarb the beer. The serving pressure and line length will be affected but the closed system that is a fully carbed beer in a keg does not.

For the same reason, bottles of beer can be shipped anywhere without having to have a special batch for Colorado or other lofty climes.

A keg is just like a 5 gallon bottle of beer.

Once opened a beer bottle at altitude will foam more if left undisturbed but it is not much as I have experienced. No doubt you have seen that too.

In short. If your beer is correctly carbonated at altitude A. It is correctly carbonated at altitude B.

I had a similar issue. Brewed a bunch of beer for a friend's wedding up in the mountains. I just dialed the serving pressure back to get a better pour. No need to decarbonate it as you want the same volumes of CO2. Ideally you would run longer lines and use the same serving pressure as you are trying to balance to a lower final atmospheric pressure.

I just brought two kegs filled in NYC at sea-level to Utah 7,000 ft and they were flat.

I was able to decarb a little and turn the serving pressure down and it worked well.

DevilNuts said:

I just brought two kegs filled in NYC at sea-level to Utah 7,000 ft and they were flat.

Click to expand...

If it was flat at 7000 ft, it was flat at sea-level. Changing the altitude won't change the carb level, or CO2 pressure inside the keg (if it is disconnected from the gas system.) What will change is the gauge pressure, since that is the difference between the CO2 pressure and atmospheric pressure.

Brew on

VegasBrew1 said:

Which would make me wonder about these balanced tap lines programs not accounting for elevation in their computation. Perhaps it only comes into play if the keg is moved?

Click to expand...

Line vs. carb level balancing is all about the gauge pressure of the CO2 in equilibrium at the carb level and temperature. The equilibrium CO2 partial pressure is constant for a particular carb level and temperature, regardless of atmospheric pressure. The gauge pressure is the difference between the CO2 partial pressure (assuming pure CO2 in the keg headspace) and atmospheric pressure. So, to get the same level of carbonation at higher altitude (lower atmospheric pressure), the gauge pressure must be increased. The line length calculators work on gauge pressure, so they don't need to be adjusted for altitude. What does need to be adjusted for altitude are the carbonation pressure calculators. The net is that you do need longer lines for the same carb level at higher elevations, but the line length calculator will tell you that if you put in the correct gauge pressure.

Brew on

doug293cz said:

If it was flat at 7000 ft, it was flat at sea-level. Changing the altitude won't change the carb level, or CO2 pressure inside the keg (if it is disconnected from the gas system.) What will change is the gauge pressure, since that is the difference between the CO2 pressure and atmospheric pressure.

Brew on

Click to expand...

After investigating, I've concluded that I had slow leaks on the gas posts, and over four thousand miles of driving the carbonation just leaked out until it was gone.