PSI problem, Is this Normal?

What should the PSI be on a full 5# CO2 tank? Does it vary? Also, will the guage show a pressure drop if the tank is placed in the refrigerator with the keg. I haven't tested for leaks but I may have one. It doesnt sound like it is leaking. I am force carbing my beer at 30 psi. I have it in the fridge because I read that it will work better on cold beer. However, it hasn't even been 24 hours yet and my guage has already showed an almopst 200psi drop. Is that normal? Does it really take that much to force carb beer?

It varies based on temperature. The pressure will lower as the temp. does. The only way to really know how much is in the tank is to weigh it - there's a tare weight stamped on the side of the tank. Weigh the tank then subtract the tare weight and that's how much CO2 you have. From what I've read, you should be able to carb and serve around 5 5 gallon cornies with a full 5# tank.

Also, if there is a slow leak, you might not hear it. A good way to check is to spray all the connections with Star San and check for bubbles.

PSI will vary based on temp

35degrees is somewhere in the ballpark of 500psi
100degrees is in the ballpark of 900psi

the high pressure guage will only really tell you when the tank is almost empty. If temp is constant, the tank can go from 100% full to 5% full, without the needle moving.

Ok. I set my guage to 30 psi to force carbonate. Now that it has been in the cold refrigerator for almost 24hrs, I notice the guage now says about 20psi. I had adjusted it back so it is at 30psi. Since it sounds like the the temp affects the gas, should I have just left it alone and not adjusted back to 30?

You were right to ajust it. With several regulators, if your imput pressure goes down, so does your output pressure. The system just needed some itme to equilize at the new temp.

I've also seen regulators that just need to break in a little bit when they are brand spankin new.

After that break in, they hold consistent psi's even if the temp changes a bit.

Thanks for the help. My guage is still holding at 30 after the adjustment. I will weigh the tank after I am done carbing this beer. Also, in regards to serving the beer, when I am done force carbing, do I bleed off the pressure in the keg or leave it and what is a good serving psi? Should it very with beer styles?

As the others have stated, 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.



Also, with regard to keeping the CO2 tank in the fridge, 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

Festmaster said:

Thanks for the help. My guage is still holding at 30 after the adjustment. I will weigh the tank after I am done carbing this beer. Also, in regards to serving the beer, when I am done force carbing, do I bleed off the pressure in the keg or leave it and what is a good serving psi? Should it very with beer styles?

Click to expand...

Once you've finished carbing at 30 PSI, you'll want to shut off the CO2 to that keg (either by removing the quick disconnect or closing the valve between the regulator and the keg), bleed off the pressure, set the regulator to your serving pressure, and turn the gas back on.

Serving pressure depends on the actual carb level you want to maintain which will depend on beer style and your preference. To me, this is one of the problems with carbing at high pressure - you won't really have your desired level of carbonization until the keg has had time to equalize at the serving pressure.

Anyway, the first chart on this page has some examples of volumes of CO2 by style. Then you can look in the second chart to find the correct PSI for your serving temperature. Ideally, that will be your serving pressure.

yermej said:

Once you've finished carbing at 30 PSI, you'll want to shut off the CO2 to that keg (either by removing the quick disconnect or closing the valve between the regulator and the keg), bleed off the pressure, set the regulator to your serving pressure, and turn the gas back on.

Serving pressure depends on the actual carb level you want to maintain which will depend on beer style and your preference. To me, this is one of the problems with carbing at high pressure - you won't really have your desired level of carbonization until the keg has had time to equalize at the serving pressure.

Anyway, the first chart on this page has some examples of volumes of CO2 by style. Then you can look in the second chart to find the correct PSI for your serving temperature. Ideally, that will be your serving pressure.

Click to expand...

cool, I think that page will help out a lot. However, I still have questions since I've never done this before. What if I just want to store my keg for later. I've forced it at 30 psi so should I leave it how it is or should I bleed of the pressure first?

Also, I was just reading on a different thread that it takes more pressure to carb at higher temp. I guess this makes sense after reading the previous replies and info. For my current keg, I set the psi to 30, which was at room temp, and then put it in the fridge. Should I chill the keg first and then carb at 30. Would that be more effecient in terms of saving C02?