Closed Loop Fermentation....ISSUES??

[Morrey]

Recently attended a seminar/meeting in which a fellow home brewer (newbie I think) stated he ferments in a closed loop tank where no off gassing is allowed to escape for the duration. I didn't have a chance to ask him about this, but I do have a major question:

Aside from the excessive pressure that is bound to develop from start to finish in a closed fermentation loop, would off flavors be an issue? I know some yeast strains throw off terrible sulfur smells, so those would get trapped in the fermenter in closed fermentation.

I use Ss Uni tanks, and will usually close the BO valve when the yeast is mostly done and has off gassed undesirable odors. If I have an OG of 1.055 and a FG goal of 1.010 (as examples), I'll frequently close the valve at 1.018 ish to finish fermentation. I often achieve 10 - 12 psi in the tank at ferm temps which gives me a head start carbing when I put the keg on gas to fine tune the carb level.

But to go total closed fermentation....is this not a recipe for off flavor disaster?

 

[Vale71]

I think you either grossly misunderstood or he was spouting nonsense. Fermenting a 12°P wort without degassing would give you almost 40 volumes of CO2. At room temperature that would create a pressure of about 35 bar, any tank used either in a commercial or in a homebrew setting would either release pressure through a pressure relief valve (a safety feature) or failing that explode with a very loud bang and possibly with casualties long before such a pressure could be reached.
But, yes, on a purely theoretical level you would have issues with off-flavors as well, provided you survived the explosion...

 

[Morrey]

I think you either grossly misunderstood or he was spouting nonsense. Fermenting a 12°P wort without degassing would give you almost 40 volumes of CO2. At room temperature that would create a pressure of about 35 bar, any tank used either in a commercial or in a homebrew setting would either release pressure through a pressure relief valve (a safety feature) or failing that explode with a very loud bang and possibly with casualties long before such a pressure could be reached.
But, yes, on a purely theoretical level you would have issues with off-flavors as well, provided you survived the explosion...

I'm relatively certain he stated he was fermenting totally closed, so maybe he is fermenting in a keg that can withstand 130 psi. IF that's the case, and considering he is a newbie, I'm sure the beer is full of off flavors the yeast would produce. It's always interesting some of the off the wall comments you are likely to hear at home brew conferences.

 

[Vale71]

A keg that can withstand 525 PSI (that's 35 bar for you 'mericans ) simply does not exist. Even if it did you'd have a hard time serving it. At 35 bar the resulting spray will be so powerful that your kegerator might actually become airborne...

 

[Murphys_Law]

Maybe he is capturing the gasses in another vessel/keg and reclaiming them later for carbonation??

I’ve seen several threads where people will use the gas from the FV to purge liquid (and O2) from a SV.

 

[isomerization]

Maybe he is capturing the gasses in another vessel/keg and reclaiming them later for carbonation??

I’ve seen several threads where people will use the gas from the FV to purge liquid (and O2) from a SV.

Even if he had 20 kegs daisy-chained together, he’d still need it open on one end to avoid the massive pressure build up described above.

Edit: I’d guess the newbie brewer either meant he close transferred or misunderstands what a closed system really means.