Normal fermentation in a closed vessel would quickly put it up to 50+ psi, not terribly safe. Theres a lot of CO2 given off during active fermentation, at 7psi I can actually hear the faint hiss of CO2 slowly leaking off.
No the natural production of CO2 is giving me all the pressure I need, the adjustable pressure relief valve (spunding valve) bleeds off whatever extra pressure while maintaining what I have it set at. The 7psi is supposedly the kind of pressure yeast feels at the bottom of a large conical commercial tank.
Dale Penrose said they are tested to 160psi, and I’ve heard of a few people carbonating in the vessels. Some have even served from them, although its more common to counter-pressure transfer to kegs. You can actually use the CO2 produced by the fermentation to prepurge your keg, just leave it attached via a ball lock QD hose for a day or two.
Check out the wiki on pressurized fermentation, or the very long thread on that other homebrew talk site. I’m a poor person to talk about it other than I have maybe the ultimate vessel for this method. It can be done with cornies or sankes as well.
I dialed up to 10psi this morning, although I haven’t tested the spgr I have a sense that the fermentation may have peaked or is peaking. I hope to get my triclamp barb in the mail tomorrow so I can hook up a picnic tap to the racking valve and get a sample without having to spray the valve out after opening to collect a sample. If the adapter doesn’t come tomorrow I’m going to go ahead and get a spgr sample.
The temp is still around 65F, I turned off my chiller unit.
I took a gravity sample tonight. As I suspected, the beer has reached 1.016 after just five days, and thats including a 24hr lag time for dry yeast. It has excellent aroma, a rocky head and a very firm bitterness. No sign of diacetyl or other green flavors other than a yeastiness. It might not be quite as black as I wanted but its tough to judge color since the sample had yeast in it. I’m going to keep it at 10psi for another couple of days, then bleed pressure and harvest yeast then dial up the pressure. I might add some priming sugar to ensure adequate carbonation, and maybe some gelatin to speed the clearing.
1.072 to 1.016 in five days, thats fast. 78% attenuation is a perfect result as far as I’m concerned.
Fully carbonated or at least mostly carbonated to where I can just adjust carbonation with my CO2 tank rather than starting from scratch. You can even purge your keg with the gas out of the fermentor, then counter-pressure fill the keg. I’ll probably put the kegs on a bathroom scale and fill them by weight.
This is part of the beauty of a pressurizable conical.
I made up a gas transfer line today and purged a keg with pressure from the Brewhemoth. That brought the pressure doen to 5psi. I harvested yeast from the dump valve into a couple of quart jars, then cleaned up the valve with a spray bottle of starsan. I bled the remainder of the pressure off and added gelatin and an ounce of Cascade for a modest dry-hopping. Sealed back up and pressurized with my CO2 tank. I decided not to add priming sugar this time, I’ll try that next time or ramp my pressure up sooner to take advantage of the initial sugars.
I’m still waiting on my barbed triclamp, brewershardware had an item on backorder and that is holding up the works. I really can’t rack carbonated beer, I need to transfer using counterpressure and for that I have to have the barbed fitting for the racking port.
Got my barbed triclamp fitting in the mail yesterday and made up a transfer line this morning, then transferred beer to two cornies using counter-pressure. That worked slick, I used the bathroom scale to tell when it was full. I still managed to blow a little foam out the relief valve but it was simple enough to clean out. I could see a few clumps of trub come through to the first keg but overall the beer looked very clear. One keg is in the fridge now and I will get to have my first pint tonight. And maybe my second and third if it tastes like I hope.
Glad you are having fun with it. I’ll be kegging ten gallons out of my Brewhemoth tonight, 10 gallons out of my other one next week. Partigyle Scotch/Scottish ale up next if I can find some nice chunks of granite…
Look up stein beer. i haven’t tried to make it yet, but it would be fun. Not traditional in Scottish beers as far as I know, but would still be interesting.