Closed Fermentation vs. using an airlock?

[KingNeptune]

I have been running a closed fermentation with a 15-17 PSI pressure release valve on all of my fermenters for years now. All of my other brewer buddies are using an airlock with a sani bucket and such. I was taught the closed fermentation by my mentor under the argument that it helps with yeast propagation. Being a commercial brewery, consistency is number one. Can any explain to me if I am totally off the mark and/or what would be the difference if I were to switch to an airlock. Thanks in advance!!
Jon Berens
Neptune's Brewery
Livingston, MT

[jwalts]

Hi Jon,

The big difference is that if one of your relief valves fail, your fermentation tank will explode - and it will be catastrophic. I'd switch to an airlock ASAP. CO2 pressure is stressful to yeast anyway.

Joe

[TGTimm]

We spund with a Handtmann pressure-control valve (in addition to the Definox PVRV) set at 15 psi, with a hose from that to a bucket of sanitizer. Belt and suspenders-if the Handtmann somehow sticks (17 years and this has never happened (but there's always a first time)), the Definox will prevent the ferm from exploding, and if the Handtmann somehow allows the ferm to suck something into the tank, it's water and PAA with some beer foam, not brewery air.

I understand that naturally carbing your beer, even if not fully, contributes to a better bubble structure, head, and lacing, but since this is the way we've always done, I can't say for sure. Our beer is usually carbed to about 1 v/v after fermentation, then we force-carb to our desired 2.5-2.6 v/v.