Pressure fermentation and carbonation question

[Rob2010SS]

So we just did our first pressure fermented beer. We did an American Porter. Let it run rampant for the first 3 days. After that, sealed it up to let the psi raise to 14 where I had the prv set.

Carbonation is affected by temp and psi, so It was my belief that because the beer was fermenting at 58F originally for the first few days and then started ramping up to 65F over the next few days, that the beer would carbonate a little bit, but not the full amount.

I went to go pull a sample today and it’s got a crazy amount of foam on it. It’s currently sitting at 65. I know people say that an advantage of pressure fermenting is carbonated beer but I would not think it would be fully carbonated. Am I mistaken on that?

Those of you who are well versed in pressure fermenting, what are your thoughts?

 

[Red over White]

So we just did our first pressure fermented beer. We did an American Porter. Let it run rampant for the first 3 days. After that, sealed it up to let the psi raise to 14 where I had the prv set.

Carbonation is affected by temp and psi, so It was my belief that because the beer was fermenting at 58F originally for the first few days and then started ramping up to 65F over the next few days, that the beer would carbonate a little bit, but not the full amount.

I went to go pull a sample today and it’s got a crazy amount of foam on it. It’s currently sitting at 65. I know people say that an advantage of pressure fermenting is carbonated beer but I would not think it would be fully carbonated. Am I mistaken on that?

Those of you who are well versed in pressure fermenting, what are your thoughts?

With 14 psi at 65°F you are at ~1.7 volumes of CO2. When you chill to serving temperature the pressure will drop, but still remain at 1.7 volumes of C02 assuming no further fermentation takes place (lager yeast commonly chews very, very slowly for me in the serving fridge). It's common to experience breakout and pour foam at high serving temperature, even with balanced lines.

Pressure fermenting does change the beer in positive ways for me, speed of maturity, mouthfeel and flavor. How does it taste to you?

 

[Bassman2003]

I have only done three full pressure batches. I noticed my Kegland spunding valve had some creep going on. So the pressure was inching upward which I needed to relieve. Maybe you are at a higher volume of CO2 than expected? While you are at that PSI, you might was well run it up to carbonation levels before the yeast is done. Then you will be fully carb'd with natural CO2. Crash cool it if you can then transfer away from the yeast after some settling time.

 

[Rob2010SS]

Thanks. Kind of what I thought. I just tasted it and it tastes great to me! Definitely would fall into the robust Porter class I think but exactly what we were looking for. I anticipate some of that roast to fade but we’ll see. I was going to say that mouthfeel seemed a little thin to me but I need to remember this is a Porter and not a stout. Taking that into consideration, mouthfeel I think is good.

I have only done three full pressure batches. I noticed my Kegland spunding valve had some creep going on. So the pressure was inching upward which I needed to relieve. Maybe you are at a higher volume of CO2 than expected? While you are at that PSI, you might was well run it up to carbonation levels before the yeast is done. Then you will be fully carb'd with natural CO2. Crash cool it if you can then transfer away from the yeast after some settling time.

I don’t think i’m at a higher co2 volume. I’m using a new Spike all in one prv, in addition to the standard prv that is calibrated to 15 psi so the tank can’t go over 15psi. Regarding your other suggestion about going all the way on the carbonation, the tank won’t support that kind of pressure unfortunately.

 

[Bassman2003]

Ok. I am enjoying pressure fermentation as another tool in the toolbox. Too bad you can't go higher with the PSI.

 

[Rob2010SS]

I’ll have to look at it more. I know on the ssbt tank we have, the prv goes at 18psi I think it is but the warning on the tank says not to exceed 30. So maybe we could go higher. Have to look into it