Problems with pressure fermenting.

[WeHeavy]

This is my first try at pressure fermenting. I have a ale that has dropped from 1.052 to 1.021 at which point I attached the spunding valve on my corny keg. I added 5 PSI of pressure and it quickly bled off. I messed around with it. I wound up adding 15 psi of pressure and bled it off to 10 lb of PSI. I got up this morning and it was reading 0. My keg has all new o-rings. Could the CO2 be absorbing into the beer? Or do I have a leak in my spunding valve?

 

[Vale71]

Since you obviously did not perform a pressure fermentation then yes, any CO2 you push into the headspace will start being absorbed by the beer. Assuming you left very little heaspace this won't amount to much in terms of carbonation and pressure may very well drop to 0 if fermentation at this point is sluggish or maybe has even stopped altogether. Of course a leak would only make things worse and make the keg lose pressure even faster.

 

[Jtvann]

This is my first try at pressure fermenting. I have a ale that has dropped from 1.052 to 1.021 at which point I attached the spunding valve on my corny keg. I added 5 PSI of pressure and it quickly bled off. I messed around with it. I wound up adding 15 psi of pressure and bled it off to 10 lb of PSI. I got up this morning and it was reading 0. My keg has all new o-rings. Could the CO2 be absorbing into the beer? Or do I have a leak in my spunding valve?

Leaky valve for sure. It could possibly be the keg, but if it sealed normally in the past, I'd expect it to be the valve.

Make sure its dialed in as tight as it will go and put it on. With a leak that fast, I'd expect you could hear the leak or at least find it with spray bubbles.

 

[Brooothru]

Since you obviously did not perform a pressure fermentation then yes, any CO2 you push into the headspace will start being absorbed by the beer. Assuming you left very little heaspace this won't amount to much in terms of carbonation and pressure may very well drop to 0 if fermentation at this point is sluggish or maybe has even stopped altogether. Of course a leak would only make things worse and make the keg lose pressure even faster.

It could also be that the lid seal didn't fully seat. A good slathering of CIP film followed with a quick burst of 10~15 psi CO2 would certainly help to seal up the keg. Another likely candidate would be the spunding valve itself. I had them not seal completely and stick slightly open enough from either krausen residue or cleaning itself that an undetectable leak occurs. Anymore I 'close' the spunding valve and pressurize the keg or fermenter slightly above the pressure I want to ferment and/or carbonate. Then, with the spunding valve in place I slowly 'open' the valve to a pressure slightly under my desired pressurization level. Once things equilibrate gradually reset the spunding valve to my actual desired pressure.

{ex: desired spunding pressure = 15 psig; close spunding valve, pressurize keg to 10 psig to seat the lid and check overall for leaks; open spunding valve to 5~10 psig once no leaks are confirmed and allow pressure to stabilize (actually it will slowly fall as CO2 goes into solution) checking periodically that pressure then remains relatively constant; as fermentation continues, pressure will increase and you'll hear gas escaping through the spund; at that time further close the valve in increments until you reach your final spunding pressure. Allow it to ferment out until pressure is stable and no further gas is escaping from the spund. Voila: pressure fermented, naturally carbonated beer!}

Brooo Brother

 

[WeHeavy]

Thank you. I should of checked the basics. I had a leak in the fittings.

 

[Brooothru]

Thank you. I should of checked the basics. I had a leak in the fittings.

Good to hear you found the cause. Slow leaks are a major pain to chase down and fix. Fortunately with kegs it can usually be reduced to only 4 things: lid, PRV or one of the 2 posts. Was your leak a post gasket or poppet, or just a loose post?

Brooo Brother

 

[Bluekat]

First pressure fermentation in my Fermzilla. Fermented at 8psi for 5 days and it looked like fermentation was complete. Decided to check the gravity so I degassed the fermenter, took off the lid and BAM, fermentation took off again almost immediately. Foam, bubbles, it was like it started fermenting over again. I put the lid back on right away with an airlock and it's still bubbling at 30 second intervals 3 days later. At this point I'm just going to let do it's thing and keg when it's done. Anyone had a similar experience?

 

[Dr_Jeff]

First pressure fermentation in my Fermzilla. Fermented at 8psi for 5 days and it looked like fermentation was complete. Decided to check the gravity so I degassed the fermenter, took off the lid and BAM, fermentation took off again almost immediately. Foam, bubbles, it was like it started fermenting over again. I put the lid back on right away with an airlock and it's still bubbling at 30 second intervals 3 days later. At this point I'm just going to let do it's thing and keg when it's done. Anyone had a similar experience?

Actually what happened is, the beer was carbonated at 8psi and when you opened the lid, you released all of the CO2 at once and it came out of solution. Anything that was at the bottom also had dissolved CO2 in it, all of the particulate matter was resuspended.