rapid pressure drop in cornie

[adm]

I'm guessing that it's just the CO2 being absorbed into the beer.

Which is kind of the problem - we're all just guessing!

Yup! Although I bet someone here knows which gas equation to use, and it sounds as if you've pretty much eliminated the option of gas leaks in the system....

If an ale is carbonated at 1 vol of CO2, but a wheat beer is carbonated at 3.5 vols, then is the pressure 3.5 times higher - and so is the gas absorbtion 3.5 times faster? I've got no idea, but there could also be a square law, or inverse square law involved here as there so often seems to be with this sort of thing.......then of course there's temperature variations to take into account too.

[lancsSteve]

No, it doesn't matter whether its soap or not, if the seals are wet and there is water adjacent to the leak it should be evident.

28 psi down to 12 psi in the matter of 10hrs, particularly if this has occured a couple of times now is excessive for absorbtion.

...if it is being cause by absorbtion, at 4 deg c and 30 psi you will have very fizzy beer (although it is dropping off from 30 as your supply isn't automatically regulated).

That's what I figured - my target for this style is high though (BrewMath gives me 3.8 vols CO2 which equals line pressure of 26psi / 179 kPa / 1.8 Bar at 4C) so going in at 30 and having it drop isn't necessarily a problem...

Absorption seems VERY high considering it's already had a week in a pressure barrel pre-corny

"There are several methods for force carbonation. The first is to chill your keg of beer down to your serving temperature, then dial up the pressure to achieve your desired carbonation level, leave the regulator set, and wait. Over time, the CO2 will dissolve into the beer until it comes to equilibrium. This can take several days to a week to occur." http://sdcollins.home.mindspring.com/Fo ... ation.html

However guess I wouldn't see this with a regulator so is it a/ midget widget or b/ leak?

As the beer becomes saturated with co2 this slows down and stops, once saturated the only way you can get more gas in is to increase the pressure or reduce the temperature. At the point of saturation, the pressure will remain stable.

The simple solution is to gas it up to 12 psi (or whatever is has stabalised at when you check it next) if it remains at 12 then absorption is probably the answer if it drops slightly top it up a couple of times but if it doesn't remain stable at this point a leak is more likely.

Ah - now there's a cunning thought / plan - and helpfully practical (and obvious) will see what it's dropping down to this eve and if it holds there. The other obvious one to look at is whether that gfigure is increasing over time e.g. was it dropping from 26psi to 2 psiu first time and now from 26 to 12 and so on - as if that going up then I guess it means that it is carbonating (and I'm being a bit dim / paranoid) exacerbated by not having kept a note of pressure it's dropping to but I think that might be creeping up...

Are you leaving the widget gas connected up now ? If so you could have a leak on there and its worth spraying water over the joins in the pipework to see if there are any leaks there.

Have been at times - there's no apparent leak there though as when disconnected it stays at the pressure overnight e.g. if keg is up to 30Psi and I disconnect the line and widget then it's still at 30 next day

The gas equation regarding carbonation is irrelevant, it's the rate at which it is absorbed at which is more relevant and that's not something that is generally considered by homebrewers. The equation and effects of co2 is summed up here in a nut shell http://brewery.org/library/CO2charts.html

Magic - yup it's the ratio f/equation for absoprtion I was after... I'm off the chart of that table though as german wheat/rye beers are 3.5-4 volumes of CO2!

[lancsSteve]

recharged it and it's dropped below 12 and continues to dro

Guess it's a leak then... Norm's been v. helpful so will get back to him on swapping it. Arrived under HIGH pressure but wonder if it's one of those ones which only shows at lower pressures...

In better news though I found a CO2 bottle supplier in lancaster with bottles at £13 and refills at £6! And a mate with a regulator - yay!