How Much Co2 Do I Have Left?

[bevdawg]

Hi all. So my regulator says my 2.6kg bottle of c02 is empty. It's been below the red mark for ages but beer keeps coming out so I've put off getting a refill. It's keeping the kpa at the mark I'm after. Anyway thought I'd swap it over tomorrow, and wondered how to tell how much is left. Wacked it on the dodgy bathroom scales and it says 7kg total weight. So am I correct in thinking the bottle is 2.6kg and theres about 4kg of co2 left?

Oh, and I keep the bottle in my keg fridge at around 4c... I just noted on the keg king site that this will affect the regulator reading and should not be taken as accurate... so maybe there's still plenty of co2 left? I'd be happy to avoid swapping it over due to time constraints more than anything. It's only poured about 1.5 kegs since new, but I think I might have had a leak at some stage...

 

[Bribie G]

Tomorrow is Friday. Therefore the bottle will be empty at 5.30 when the depot closes. Murphys. B)

My buddy round the corner invested about $15 bucks on some Woolies bathroom scales and keeps his bottle permanently sitting on them. If you grab a new scales when the bottle finally gives up the ghost, sit it on the scales and 'adjust' the dial to zero then plonk the new bottle onto the scales, this will in the future give you a more accurate reading than the reg.

Problem with the reg is that CO2 under the huge pressure it is in the bottle, is mostly liquid with a gaseous headspace. Due to the laws of physics the gas in the headspace will always be at the same pressure during the life of the bottle and when the needle drops into the red it's a sign that what's left in the bottle is just compressed gas, not liquid, so the cylinder is really on its last legs.


4k? I think the scales may indeed be dodgy <_<

 

[bevdawg]

Just double checked and weighed myself on the scales, then held the bottle and did it again, and it's about 7.5kg extra... how much should a full 2.6kg bottle weight? Anyone know?

 

[BenH]

There should be some numbers stamped on the bottle - that's the tare (empty) weight.

 

[bevdawg]

No nothing on there mentioning TARE weight. It just has dates, the keg king URL (I'll call em morrow), and "4 litres 2.6kg". Maybe it's 4litres (4kg) plus 2.6 weight of the bottle = 6.6kg?

 

[mwd]

The 2.6Kg refers to the weight of the CO2 when the bottle is full. You need to know the weight of the cylinder when empty to calculate how much gas is left.