ajustable pressure release valve

[Grott]

The KK adjustable pressure release valve with gauge instructions only stated you need to turn the adjuster at the end of the unit to set the required pressure (from 0 to 15psi).

If you want to naturally carb a keg how do you set the unit at say 12psi after priming the keg? Do you wait until pressure has built up and adjust back slowly? If the pressure is over max. 15psi on the gauge when attaching to the gas disconnect does this damage the gauge?

Thanks in advance

 

[mash head]

Just a guess, but I would wait until the yeast are active and wind the pressure up to where you want it, but I spoze you would need to over carb it to get the relief valve working as not enough priming sugar and you wont reach 12 psi to get the valve opening but check a priming chart for the relative pressures vs grams per lt.

 

[Drew]

I doubt the pressure relief valve will purge the gas quickly enough to avoid the needle maxing out at 15, if the pressure exceeded 15. (My 30 psi gauge is useless, uncalibrated and no longer linear - after connecting it to a 40 psi keg by mistake).

So I think you need to make sure you've got the pressure release valve connected during the carbonation phase, even if it's set to 15 psi. Once it's reached a reading above 12, you can dial it back as required.

 

[TheWiggman]

The way those gauges work is they have either a wound tube or arc that expands/opens when pressurised. As it opens it rotates the needle. If there is a small pin limiting the movement of the needle on the face of the gauge then there is the potential that the needle will snap or will come off on the pivoting pin (in the middle). If not, it will continue to rotate then wind back to its original position as long as you don't over-pressurise the gauge.

If your case you'll need to purge the keg anyway yes? So -

1. Add sugar and scrumptious beer
2. Put lid on and connect CO2
3. Set pressure to 90kPa and purge headspace
4. Attach PRV and wind back to 80 kPa or 12 PSI in the old money

 

[Lyrebird_Cycles]

If you are keg conditioning and you have the priming addition right, what function does the pressure relief valve serve? Is it just there as a safety measure?

 

[Danscraftbeer]

If you are keg conditioning and you have the priming addition right, what function does the pressure relief valve serve? Is it just there as a safety measure?

That's what I was thinking. if you have the correct priming sugar amount you don't need a release valve.
Also, you can replace the 15psi with an 80psi guage.
Also, when I pressure ferment it finishes naturally carbonated. My experience I finish it at 22psi which seems to be around the 2.4 carbonation volume.

 

[Grott]

Thanks all. Didn't get for just natural carb on some brews ( in case don't get priming right) , also good for possible over carbonation when force carbing and keg to keg transfer.
Cheers

 

[Danscraftbeer]

Yep. Good for all that. I have the KK one. It is consistent as long as the forcing pressure is consistent. Like transferring with bottled co2.

Fermenting under pressure is a bit more tricky I find it has to be monitored regularly. Because the co2 produced varies at different stages of fermentation the release valve needs adjusting. Its tricky like that. Like when in full blow stage. Or maybe its a malt residue in the gas released that gums up the diaphragm. An example on pressure fermenting you can set it at 5psi one night on a new brew then the ferment gets into full bore overnight and its reaching 15psi in the morning and you have to back off the release nob. I don't believe these variations have any bad effect on the beer though. Big volume commercial brews are up there in pressure on the yeast cakes etc.
Its seems to point at around 23psi/ 1.5Bar as a norm. For fermentation. The sweet spot?

Experts please chime in here tell me if I'm wrong. (or my gauges are wrong)

 

[malt junkie]

40 psi and your yeast should be dead. The bit that has always intrigued me is do yeast get the bends the way this thread goes you guys are bring em up and down at a rate of knots.

 

[Danscraftbeer]

The bit that has always intrigued me is do yeast get the bends the way this thread goes you guys are bring em up and down at a rate of knots.
40 psi and your yeast should be dead.

That is the question. I max out the pressure at 22psi at the end of the ferment when you raise it for the diacetyl rest.
Do yeast swim around from top to bottom in a 20000lt fermenting vessel?

Should this yeast subjected at various pressures be good to recycle? I do. Only 2 cultures (3 recycles) I have gone to so far. That's good yeast and cash saved and convenient.
My recycled yeast used fresh is always at least as good as the original as far as I can monitor.

 

[moonhead]

Would 15 psi at fermentation temperature even be enough to force carb? Looking at the carbonation chart, you'd want around 14 degrees max to get 2 vols at 15psi...

 

[Lyrebird_Cycles]

40 psi and your yeast should be dead. The bit that has always intrigued me is do yeast get the bends the way this thread goes you guys are bring em up and down at a rate of knots.

The pressure limits of standard yeasts vary, but figures of 50 - 200 MPa are common (see for instance this paper)

In backwards units, that's 7,000 to 28,000 PSI, not 40.

Your fermenter will give out long before the yeast do. To survive 200 MPa with a standard safety factor using SS, the fermenter walls would need to be as thick as the fermenter was wide. A 30 litre fermenter would weigh half a tonne.

 

[Danscraftbeer]

Holy fuckload Lyerbird. That gives me confirming confidence in an official sense.

Moonhead: That sounds right to me.

I will start a Lager at 10c. Set it at 5psi for the main 90% of the ferment give or take a lot! (max 22psi).
Aim the end of ferment at 15c at 22psi. Over 2 weeks total. Then chill it to as low as 5c to 0c to transfer into serving kegs and it is drinkable but a little cloudy at this early stage. Another week its clearer, The longer chilled the better for lagers so they say etc.

 

[malt junkie]

The pressure limits of standard yeasts vary, but figures of 50 - 200 MPa are common (see for instance this paper)

In backwards units, that's 7,000 to 28,000 PSI, not 40.

Your fermenter will give out long before the yeast do. To survive 200 MPa with a standard safety factor using SS, the fermenter walls would need to be as thick as the fermenter was wide. A 30 litre fermenter would weigh half a tonne.

I'll have to track down the paper I read that in and post, it maybe that I mis-read, it was in among one of the specific pressure ferment threads.

Always thought it was a little strange, considering some of the reaction vessels they use in other industries.

Ed punctuation

 

[Lyrebird_Cycles]

Yep.

The reason I went looking is that I know that sparkling wine routinely hits 500-600 kPa (70 to 85 PSI) so 40 had to be too low.

 

[Lyrebird_Cycles]

A 30 litre fermenter would weigh half a tonne.

Sorry I dropped a figure from the "back of the envelope" calc for this, make that "a 30 litre fermenter would weigh about 4 tonnes"

 

[husky]

I have one of the attached relief valves to try when I get my conical sorted. The X201 model has a max setting of 29psi so hopefully wont be possible to over pressurise the fermenter. Was planning to set to 10ish psi during the main ferment and raise to 20 at the end allowing to transfer carbonated beer to the keg. From what I have read fermenting under pressure produces a cleaner taste which will be interesting to sample.