Spunding Valve for lagers - When to carbonate

[jamest22]

I am going to start carbonating my lagers using a spunding valve but have a few questions. Hopefully someone with experience spunding and perhaps a little knowledge about how the process is applied in traditional German brewing can ring in.

In traditional German brewing, when carbonating lagers naturally using a spunding valve, at what stage is the vessel capped to begin carbonating? Is spunding always performed in conjunction with krausening?

It seems that unless the beer is being krausened prior to carbonating, that carbonation and diacetyl rest time would overlap.

Also, it seems to me that when spunding, the beer will always have to be fully carbonated before lagering. Otherwise it would have to be krausened after lagering to carbonate which wouldn't make much sense to me. Is this correct?

 

[Lennie]

I actually ferment under pressure so I'm spunding right out of the gate. I usually go with 7psi and ramp to 15psi after four or five days. Pressurized fermentation is supposed to make a cleaner/lower ester profile, something desireable for lagers.

If you start your diacetyl rest at around 80% of the way to FG you will have plenty of CO2 to carbonate your beer. And yes you would carbonate before lagering or you'd have to krausen and it'd be tricky to introduce the spiezen without introducing air, but it could be done. I kind of think carbonation prior to lagering helps prevent oxidation by keeping the container pressurized and seals intact.

 

[jamest22]

I actually ferment under pressure so I'm spunding right out of the gate. I usually go with 7psi and ramp to 15psi after four or five days. Pressurized fermentation is supposed to make a cleaner/lower ester profile, something desireable for lagers.

If you start your diacetyl rest at around 80% of the way to FG you will have plenty of CO2 to carbonate your beer. And yes you would carbonate before lagering or you'd have to krausen and it'd be tricky to introduce the spiezen without introducing air, but it could be done. I kind of think carbonation prior to lagering helps prevent oxidation by keeping the container pressurized and seals intact.

Thanks. It sounds like you must be fermenting in a corney or pressurizable conical though. I will be fermenting in a carboy, so in order to carbonate via spunding I will need to transfer the beer out of the carboy before or during diacetyl rest, which doesn't sound like a good practice to me.

 

[Lennie]

Yes I ferment in a 5gal corny and I also have a pressurizable conical.

Why do you think transferring would be a bad practice? As long as you transfer a decent amount of yeast cake I don't think it would hurt anything, and the beer is saturated with CO2 so oxidation will be kept to a minimum. You might be better off just krausening though. Heres an article that talks a little about both, its about halfway down.

http://www.trailmonkey.com/lounging/yeasty.htm#Spunding

 

[jamest22]

Yes I ferment in a 5gal corny and I also have a pressurizable conical.

Why do you think transferring would be a bad practice? As long as you transfer a decent amount of yeast cake I don't think it would hurt anything, and the beer is saturated with CO2 so oxidation will be kept to a minimum. You might be better off just krausening though. Heres an article that talks a little about both, its about halfway down.

http://www.trailmonkey.com/lounging/yeasty.htm#Spunding

So after primary fermentation and spunding carbonation are complete, do you transfer the carbonated beer into a serving keg for lagering?

 

[VladOfTrub]

I'm not sure if you have a grasp on what a spunding valve does. The valve limits the pressure in the tank. It's an adjustable relief valve. It is used to control carbonation pressure after the beer is racked from the fermenter into the settling tank, a keg, or within a sealed fermenter itself. When the beer is transfered, the yeast will be somewhat roused up and will start working again. The valve will keep the pressure constant in the vessel. Without a relief, the vessel can possibly rupture. That same thing just happened recently in a brewery. Get a Klinitest. Test the fermenting beer. When the glucose level is around 15-20%, do the 60-65 degree D. rest. Test the brew during the rest. When the glocose is about 5%. Rack the beer into a keg. The yeast will work on the residual fermentable sugar, carbonating the beer. If glucose level is 0-2%, krausen, prime or gas it. You can get into trouble with a spunding valve. If the brew is transfered without knowing when fermentables are low enough to safely carbonate naturally, or if krausening, and it goes wild, or if temp isn't maintained. The brew can foam out through the valve, clogging it. A commercial valve designed for brewing, is in no way shape or form built like the valves DIYers are building. However, the principles are the same and that's where it ends....You may want to develope a good Lager brewing procedure and get good equipment, before getting into what you're thinking of doing. You have the cart in front of the horse.

 

[Lennie]

So after primary fermentation and spunding carbonation are complete, do you transfer the carbonated beer into a serving keg for lagering?

I've done it both ways and didn't find a huge difference. After lagering I rack to another keg using a pressurized transfer and I'll purge the new keg to remove air.

Vlad I concur with the observation that if you get blowoff into the spunding valve it will clog. Been there done that, the reduction in krausen is apparently not dramatic. Both of my systems (conical and corny) have secondary relief valves so I don't think vessel rupture is likely. While I'm not convinced that spunding is necessary to produce good lager or ale, I don't see it being in any way detrimental. It minimizes oxidation and fits hand in glove with pressurized transfers. I don't think it would be "putting the cart in front of the horse" to employ this in conjunction with a proper ferm/lagering schedule. I look at it as just doing everything right at once. Spunding really doesn't change much as far as timing and schedules. It just puts the process under a modest positive pressure from CO2 which keeps air/O2 out quite nicely.