Keezer question - CO2 tank inside or out?

Is there any advantage (other than more space for kegs) in keeping the CO2 tank outside of the freezer as opposed to inside? I am planning on doing a batch soon before building a collar for the chest freezer. I plan on just keeping the keg and CO2 tank inside the chest freezer and using a picnap tap for the time being. Opinions welcome.

 

The high-pressure gauge (if your regulator has one) will read accurately if the tank is at room temperature, and obviously it's easier to make pressure adjustments if the tank is outside.

FWIW, I keep my tanks inside both my kegerator and my cold-conditioning fridge.

 

Actually, the high pressure gauge will still read accurately at fridge temps. It will just read lower due to the pressure/temperature relationship of CO2 in a liquid/vapor state.

CO2 in a liquid/vapor state has a direct pressure/temperature relationship, as can be seen in the chart below. The pressure will stay the same, at a given temperature, until all the liquid has been vaporized. Once only vapor exists, the pressure in the tank will drop rapidly. As the others have stated, the only way to know for sure how much liquid CO2 is left in the tank is to weigh the tank, and subtract the tare weight that's stamped on the side of the tank.

 

I understand the science involved...the point is that when the tank is chilled, the high pressure reading is no longer meaningful or useful. My gauge goes almost to zero once a full tank is chilled, and stays there.

 

I'm not trying to be argumentative, but the high pressure gauge reading is virtually meaningless regardless of where the CO2 tank is. It will read EXACTLY the same, AT A GIVEN TEMP, until all of the liquid CO2 has been vaporized.

If your gauge is reading close to zero when the tank is in the fridge then your gauge is faulty. At 40˚F, the high pressure gauge should read 567 psi. That P/T chart that I posed is extremely accurate.

 

+1
I'll never spend the money for a dual gauge regulator again. put that money toward another 5# tank so you can have a spare, and quit worrying about the tank pressure...it doesn't mean much of anything anyway.

 

When I say that the high pressure gauge is virtually meaningless, I don't mean that it's completely meaningless. When I see the high side pressure drop below 500 psi at my fridge temp of 40˚F I know that I've only got vapor remaining in the tank and it's time for a refill.

As I don't have my tanks sitting on a scale, if I had a regulator without a high side gauge then I wouldn't know they were almost out of gas until I saw my serving pressure gauge start to drop under ~12psi.

 

I have an "outy".

I like the convenience of seeing and adjusting the dial outside the keezer, plus...that (20 pounder) is a bitch to lift in and out over that collar.

 

Another consideration, which is only minor, in keeping the CO2 tank, and therefore the regulator in the fridge is that the elastomer that is used for the regulator's diaphragm will be slower to respond to changes in output pressure when it's cold.

For example. If you have the regulator in the fridge and set to 10 psi and then you change the output pressure to 12psi, you may find that when you come back in a couple of hours that the new output pressure may be 15 psi. This "creeping" effect is due to the cold temps effecting the diaphragm. I've learned to compensate for the "creeping" effect by setting the new output pressure just slightly lower than my intended pressure. It will then creep up to my new setting after some time. Usually not very long.

 

My practical advice to the OP remains the same...the high pressure gauge has some usefulness when the tank is at room temperature, and virtually none when it's chilled. Outside, I can tell at a glance if the tank has run dry. Inside, it's not obvious, as there is only the slightest needle movement between freshly filled and empty.

All three of my Co2 rigs respond to temperature in exactly the same way, I guess they haven't seen your chart.

 

I like keeping my tank outside of the fridge. It's more of a personal preference than anything else and it lets me get an extra keg in the fridge.

 

I keep mine outside because there is not enough room inside.

 

I keep mine inside with the keg(s). It will read 800 psi at room temperature and a little under 600 inside the fridge.

 

Sorry for reviving the old thread but. My tank 20# is inside the keezer (7 C) so approximately 45 F. The gauge indicated 1500 psi at room temp or something along this number. Now in the keezer either I have a leak or something is wrong because It shows 400ish psi now.