Batch priming a pressurized fermentation

[GRJBowers]

I'm thinking about getting a pressurizable fermentation vessel. The problem is, I only have 2 kegs at the moment so when the fermentation is finished, I would probably bottle from the fermentor. As I understand it, CO2 solubility is a function of temperature and pressure. So using a kegging CO2 chart it looks like that at ale fermentation temperatures (say 68 °F for example), I would need to ferment under 30-ish PSI to hit a carbonation level of 2.5 volumes. I'd rather not ferment under that kind of pressure since I can't see it being conducive to yeast health.

I was looking at the Braukaiser website here and it looks simple enough to figure out how much priming sugar I need assuming I know the CO2 content of the starting beer.

Given my current situation I have a question: would a kegging chart be accurate enough for figuring out the CO2 content of my fermented beer? Using a fermentation of 68 °F at 15 psi as an example, would I end up with just under 1.7 volumes of CO2 in the finished beer?

Any insight would be appreciated.

 

[hopjuice_71]

Just thought I would throw this out there: have you considered fermenting in kegs? Sounds like you are already setup to handle kegs so I though it might be worth making the suggestion. After trying this I have now switched to fermenting ~80% of my batches in kegs. There is really only one downside and this is smaller batches of ~4.5 gallons. There are some huge upsides though. My processes is to cut ~1 inch off the dip tube to reduce trub pickup but it can be turned back into a serving keg just by adding a bit of silicone tubing to the bottom of the dip tube. The foot print of a keg means you can usually fit several into a typical fermentation chamber, like an adapted fridge or chest freezer, and so doesn't have the need for any fancy temperature control. I attach a QD with some tubing to the gas post for blowoff and let the fermentation ride until nearly the end. One of the big advantages then comes in - I can attach a spunding valve (a 20$ item) to the gas QD near the end of fermentation to capture the CO2 and carbonate the beer. The spunding valve allows me to tune the carbonation by just dialing the pressure based on temperature and desired CO2 volumes, just like force carbonating. However, I have also had good luck achieving the same effect just by sealing the keg towards the end of the fermentation without a spunding valve. Once this is all done I can cold crash for as long as I like with no worry of O2 ingress and the end result is finished carbonated beer. I then closed pressure transfer to a serving keg with a jumper (beverage out to beverage out) but, in your case, I could see bottling directly from the cold crashed fermentation keg using a beer gun or something. Note that everything here can be done under closed O2 free conditions and with pressure transfers - exactly what a keg was designed to do - which helps keep the beer fresh. If this hasn't at least made you think about it, maybe this will: several used stainless steel kegs will set you back far less $$ than any other fermenter that can hold pressure, even the plastic Fermentasaurus. Just a thought, hope its useful.

Cheers

 

[bfaulds6]

I'm thinking about getting a pressurizable fermentation vessel. The problem is, I only have 2 kegs at the moment so when the fermentation is finished, I would probably bottle from the fermentor. As I understand it, CO2 solubility is a function of temperature and pressure. So using a kegging CO2 chart it looks like that at ale fermentation temperatures (say 68 °F for example), I would need to ferment under 30-ish PSI to hit a carbonation level of 2.5 volumes. I'd rather not ferment under that kind of pressure since I can't see it being conducive to yeast health.

I was looking at the Braukaiser website here and it looks simple enough to figure out how much priming sugar I need assuming I know the CO2 content of the starting beer.

Given my current situation I have a question: would a kegging chart be accurate enough for figuring out the CO2 content of my fermented beer? Using a fermentation of 68 °F at 15 psi as an example, would I end up with just under 1.7 volumes of CO2 in the finished beer?

Any insight would be appreciated.

Did you ever figure this out? Just comin across this thread now and am also interested in batch priming a beer for bottling after fermenting under pressure.

 

[GRJBowers]

Did you ever figure this out? Just comin across this thread now and am also interested in batch priming a beer for bottling after fermenting under pressure.

Not really. It was a while ago so I don't remember which batch this was. The biggest problem I see is figuring out how much CO2 would be lost in the bottling. If I were to try this again, I would put the priming sugar solution into a keg and pressure transfer from the fermenter into the keg, let it carb, then chill it and bottle using a bottling gun or a counter-pressure bottle filler. That said, if you have the kegs and a CO2 bottle, you could skip the priming sugar and just force carbonate it the rest of the way. Sorry I couldn't be more of a help.