Spunding question

[JWeave16]

So I have a spunding valve for my SSBrew unitank and I've always had good results. On my most recent brew on day 3 I went to shut off the blowoff and switch over to spunding (.8 bar) as my lager is about 1/3 of the way fermented. This morning I check it and small bubbles just started coming out like normal. About 3 minutes later a huge burst of air came out shooting sanitizer everywhere... never had that happen so I refilled the sanitizer cup thinking maybe it was some fluke. Well again a minute later I had the same issue. Well needless to say I shut the spunding valve off and now have the blowoff tube hooked back up. I've searched for answers on what is going on but for the life of me can't find anything. Any ideas? Too high a krausen? Potential blockage in the gas ports in the spunding valve? Thanks.

 

[SanPancho]

sounds like something with the spunding valve. it shouldnt have a big blow off. once you get up to 12 or 13psi you should be getting small, relatively tame and steady release of gas. the beer would have to be fermenting like crazy to build up pressure so fast that it comes out like a crazy burp.

maybe try adjusting the spund a few times and see if that helps. lower the pressure, raise it back up, lower it, raise it back up.

if that doesnt work i'd put the blowoff back on, pull the spund and see if you can disassemble and inspect. kind of sounds like the diaphragm is sticking and not flexing smoothly.

 

[JWeave16]

sounds like something with the spunding valve. it shouldnt have a big blow off. once you get up to 12 or 13psi you should be getting small, relatively tame and steady release of gas. the beer would have to be fermenting like crazy to build up pressure so fast that it comes out like a crazy burp.

maybe try adjusting the spund a few times and see if that helps. lower the pressure, raise it back up, lower it, raise it back up.

if that doesnt work i'd put the blowoff back on, pull the spund and see if you can disassemble and inspect. kind of sounds like the diaphragm is sticking and not flexing smoothly.

Yeah definitely first time I've seen anything but small bubbles. Once I hooked back up the blowoff it did blow so Krause off so I've thinking maybe a mixture of a blockage and valve not operating quite right.

 

[SanPancho]

that's dangerous. if your spund got sticky and isnt operating smoothly then its not much of a leap to think that maybe your PRV might also have gotten some crud in it.

while its going off and putting out krauzen and co2 you're safe from oxygenating your beer. very good time to dissemble and clean your spund AND check your PRV.

one last note- everyone has their own procedures and habits, but putting the spund on at the beginning at something pretty low like 2 -3-4 psi will help keep krauzen down and help avoid the situation. if i recall chris white said in his book that generally anything under 7ish psi wont have a negative affect on yeast growth. thats why alot of folks wait to spund, but im my experience if you start low there's no noticeable effect. personally- i start with the spund on my serving keg at 2psi, run jumper from fermenter to keg to purge keg of oxygen. two birds, one stone.

 

[Zenmeister]

I've had that before. What happens is the spring inside the pressure assembly gets stuck, then when pressure builds up enough it esssentially burps. So, when cleaning the spunding valve, make sure to take it apart and clean that part of it as well.

 

[JWeave16]

I've had that before. What happens is the spring inside the pressure assembly gets stuck, then when pressure builds up enough it esssentially burps. So, when cleaning the spunding valve, make sure to take it apart and clean that part of it as well.

Good to know. Thanks for the info.