spunding for carbonation

[hoppyscotty]

Got a current brew fermenting. the plan for this one is to close off the fermenter about 3/4 the way through fermentation and spund primarily for carbonation. My question is what temp/pressure combo do I need? do I just use a normal carbonation chart for the pressure level? also I'll be cold crashing so I guess once fermentation is over and the beer carbonated I then put the tank under CO2 pressure to maintain that or actually increase pressure as the beer cold crashes?

For those who've done this before what procedure do you follow?

Thanks

 

[Sadfield]

I find the usual pressure charts work fine for this. As the charts show, you need less head pressure when carbing at lower temperatures, when applying co2 top pressure. Which also means the head pressure in the closed vessel, built through spunding, will lower as you cool, with the beer taking on more co2. If you give it a little time at the cooler temperature to reach equilibrium, you should then be able to calculate if any extra top pressure is needed to reach your desired CO2 volume.

 

[hoppyscotty]

Brill thanks...I was thinking setting pressure according to carbonation level at fermentation temp then when I set to cold crash put on CO2 at the colder and higher pressure to maintain carbonation.

Any idea if I need to increase fermentation temp as I start to spund while fermentation is finishing?

 

[Sadfield]

You could raise the fermentation temperature, it'll do a diacetyl rest at the same time.

 

[RoomWithABrew]

Hi I do this all the time.
Decide on the vols of co2 you want in finished beer.
Look at the temp and psi chart for those vols at the temp you are fermenting at. Ie the D rest temp.
Set spunding valve to that pressure, it will be high. Something like 30 psi at 28 c if using kveik and pressure ferment lager etc.
Finish D rest and ensure ferment finished.
Then cold crash you will see pressure fall and it will with time balance again to your original vols target.
As it warms to serving temp you will see pressure rise on gauge again in balance.
Getting it right means you can purge your keg, cold crash, closed transfer and fill keg with clear beer. Then put on tap balanced straight away.

 

[hoppyscotty]

Hi I do this all the time.
Decide on the vols of co2 you want in finished beer.
Look at the temp and psi chart for those vols at the temp you are fermenting at. Ie the D rest temp.
Set spunding valve to that pressure, it will be high. Something like 30 psi at 28 c if using kveik and pressure ferment lager etc.
Finish D rest and ensure ferment finished.
Then cold crash you will see pressure fall and it will with time balance again to your original vols target.
As it warms to serving temp you will see pressure rise on gauge again in balance.
Getting it right means you can purge your keg, cold crash, closed transfer and fill keg with clear beer. Then put on tap balanced straight away.

Thanks for the at perfect. I put under pressure last night with about 15 points left to go but chickened out at targeting the very high pressure off the carb chart so settled for 10 psi on the basis I get it partially carbonated at least. I also bumped up the temp by a degree. Not for any particular reason! I was worried I might stall fermentation too.

It still has 9 points to go so do you think I should ramp it up more? And what should I do with the temp?

 

[RoomWithABrew]

I would ramp the temp as pressure may suppress activity but I've actually not really found this even fermenting up to 35 psi.

I'd go for your target pressure as I discussed above and do the temp bump. All should be fine if your vessel is okay with those pressures.