Pressurised fermentation length

[clyne]

Hey experts. So, first attempt at pressurised fermentation recently using a corny keg and a keg land sounding valve. I was expecting fermentation to take a little bit longer than traditionally but it’s been in the keg sitting around 19C for almost 6 weeks now (cranked up at 21C for the last week to try to hurry things along), but it’s still producing CO2. As it’s in a keg under pressure I don’t really want to take samples to test FG.

Anyone any thoughts on whether this is normal or not? I’ve increased the pressure on the spunding valve recently from around 30PSI to 40PSI to see if that makes any difference (my thinking being will those force more of the CO2 into solution?). Was I too high in the first place at 30PSI?

Ideas and suggestions welcome

 

[YeastFace]

It's generally quicker as you ferment at higher temperatures. There will be Co2 in solution, so I wouldn't take that as a sign it's still fermenting.

I think at 6 weeks you can be quite sure fermentation is done and you'd be wanting to get it transferred.

 

[LeeH]

Being under pressure, it’s a perfect way to take a sample.

 

[Soton]

Brewing under pressure allows you to ferment at higher temperatures that will aid the speed of fermentation, also it’s better for taking samples because you won’t introduce oxygen into the tank when you take a sample
You maybe getting signs of co2 escaping as it coming out of the beer because it was lightly carbonated during fermentation. I would take a couple of readings over the next couple of days but I would expect the fermentation to of finished by now

 

[RichardM]

Brewing under pressure allows you to ferment at higher temperatures that will aid the speed of fermentation, also it’s better for taking samples because you won’t introduce oxygen into the tank when you take a sample
You maybe getting signs of co2 escaping as it coming out of the beer because it was lightly carbonated during fermentation. I would take a couple of readings over the next couple of days but I would expect the fermentation to of finished by now

If it's been at 30 to 40 psi for weeks it will be more than lightly carbonated.

 

[Soton]

If it's been at 30 to 40 psi for weeks it will be more than lightly carbonated.

Why is so highly pressured?

 

[RichardM]

Why is so highly pressured?

You need to ask @clyne , not me

 

[LeeH]

Why is so highly pressured?

Go big or go home.

 

[MickDundee]

I usually pressure ferment at 5-10PSI.

I know you’re doing it in a corny, but 30-40psi would probably explode a Fermzilla (which has a 35PSI pressure limit)!

 

[Ossiary]

I’d highly recommend watching some of the YouTube content by DrHans. Good information about fermenting under pressure and also pushing the pressure/temp higher than normal which might be useful for you if that’s what you’d like to try. I’ve brewed a few batches under pressure in Cornys, but never as high a pressure as you have, usually about 10 - 15psi. I agree that it’s very unlikely that the fermentation is ongoing after 6 weeks at 19c. However, depending on the yeast you’ve used the higher pressure may not have been optimal for its performance. Do you have a way of taking a sample? You can SLOWLY reduce the pressure using the spunding valve to about 15psi and then use a picnic tap to take a sample. It’ll be foam, but will settle to liquid. Looking at a carbonation chart for 19c and 30 to 40psi you’ll be looking at a lively beer of about 2.7+ Vols of CO2.
Definitely look into how to transfer a carbonated beer into the serving keg. For one possibility, my process is to cool the receiving tank as low as possible, pressurise the receiving tank to same pressure as fermentation tank (probably reduce to about 15psi for transfer), move the unadjusted spunding valve onto the Gas In post of receiving tank to let you ensure they are same pressure. Connect a jump line of two disconnects joined by a short tube to both tanks Liquid Out posts. Slowly reduce the pressure in the receiving tank using the spunding valve by up to 5psi lower than fermentation tank and watch the beer flow through the connecting pipe. Should be low/no foaming in the tank if done gently enough.

 

[clyne]

Being under pressure, it’s a perfect way to take a sample.

I can’t believe I was so stupid to miss this. It’s in a serving keg!

 

[clyne]

I’d highly recommend watching some of the YouTube content by DrHans. Good information about fermenting under pressure and also pushing the pressure/temp higher than normal which might be useful for you if that’s what you’d like to try. I’ve brewed a few batches under pressure in Cornys, but never as high a pressure as you have, usually about 10 - 15psi. I agree that it’s very unlikely that the fermentation is ongoing after 6 weeks at 19c. However, depending on the yeast you’ve used the higher pressure may not have been optimal for its performance. Do you have a way of taking a sample? You can SLOWLY reduce the pressure using the spunding valve to about 15psi and then use a picnic tap to take a sample. It’ll be foam, but will settle to liquid. Looking at a carbonation chart for 19c and 30 to 40psi you’ll be looking at a lively beer of about 2.7+ Vols of CO2.
Definitely look into how to transfer a carbonated beer into the serving keg. For one possibility, my process is to cool the receiving tank as low as possible, pressurise the receiving tank to same pressure as fermentation tank (probably reduce to about 15psi for transfer), move the unadjusted spunding valve onto the Gas In post of receiving tank to let you ensure they are same pressure. Connect a jump line of two disconnects joined by a short tube to both tanks Liquid Out posts. Slowly reduce the pressure in the receiving tank using the spunding valve by up to 5psi lower than fermentation tank and watch the beer flow through the connecting pipe. Should be low/no foaming in the tank if done gently enough.

Good advice here thank you. I’m new to pressure fermenting and wanted my beer fairly well carbonated. But yeah I may have overdone it first time around. Time will tell, but I’ll keep ya all in the loop.

Thanks all for the advice and pointers

 

[RichardM]

I can’t believe I was so stupid to miss this. It’s in a serving keg!

A lot of people pressure ferment in a corny, but then close transfer to another keg for serving.

 

[LeeH]

I can’t believe I was so stupid to miss this. It’s in a serving keg!

You’ll need the filter on the floating dip tube or the poppet may block