Could a keg manometer measure carbonation level?

[javert]

Been getting flat beer on kegs despite apparently having enough pressure and low enough temperature, so I'm researching how to measure carbonation.

Turns out the Zahm is quite expensive and the Gehaltemeters are even higher priced. Looking at the Taprite tester, turns out that it is merely a vessel that is filled and pressurized from the keg and which measures pressure and temperature to calculate the carbonation level.

If measuring pressure and temperature on a closed vessel is all what is needed, what prevents us from just attaching a manometer to the keg through the ball / pin lock and calculate the carbonation provided the temperature of the keg is the one from the freezer? I guess headspace is the key difference here since the testers are filled up completely to displace air. Is the headspace relevant in here to nullify the manometer results?

 

[Vale71]

If measuring pressure and temperature on a closed vessel is all what is needed, what prevents us from just attaching a manometer to the keg through the ball / pin lock and calculate the carbonation provided the temperature of the keg is the one from the freezer?

Absolutely nothing. As a matter of fact I believe that's how literally everybody who kegs measures their carbonation level as professional CO2 meters are horrendously expensive for a homebrewer. To prevent inaccurate measurement you need however to purge the headspace of air (which is a must in itself beacuse of oxydation concerns) and if force carbonating let the beer rest for a while after disconnecting the CO2 tank to make sure you're actually measuring the CO2 concentration of the beer.

 

[day_trippr]

If I have a question about the carbonation level on a keg I snap my spunding assembly on the gas post with the valve fully tightened and read the head space pressure (having popped the prv prior then allowing the keg to equalize)...

Cheers!

 

[postalbunny]

If you want to know the vols of co2 then what Day_trippr suggested is about the only cheap way todo it... buy a spunding valve or the parts to make one. You can pop it on and leave it for 24hrs, come back the next day and note the pressure and temp. You can look this up on a chart and see where you're at. Sounds like that's all the tapright model is doing.

I'd suspect you're having other issues if you're really having flat beer come out of the kegs.