Pressure fermentation in a Corny Keg

[rconway91]

Trying my first pressurized fermentation. I purchased a spunding valve that connects to the gas connect on my pin lock corny keg. I am making a Helles Lager at room temp using Omega Lutra at 15 psi. I have some questions about fermenting in a corny under pressure

1. How much head space do I need? My current batch was 4.7 gal and there has been no sign of blowout getting to the spunding. Is the pressure keeping the krausen down? Could I go more (4.8 - 4.9 gal)?

2. Do I need pressurize the keg right away once I pitch the yeast or can I just wait until until it self pressurizes?

3. I cut 1" off the bottom of the liquid dip tube to avoid sucking up the yeast when I transfer. I this the best way? Would some sort of floating intake be better?

 

[VikeMan]

I cut 1" off the bottom of the liquid dip tube to avoid sucking up the yeast when I transfer.

Unfortunately, the trub from a 4.7 gallon batch in the diameter of a corny keg is going to be deeper than an inch.

 

[Vale71]

1. How much head space do I need? My current batch was 4.7 gal and there has been no sign of blowout getting to the spunding. Is the pressure keeping the krausen down? Could I go more (4.8 - 4.9 gal)?

Pressure keeps the Kräusen down but I would still avoid cutting it too close.

2. Do I need pressurize the keg right away once I pitch the yeast or can I just wait until until it self pressurizes?

With corny kegs it's best to pressurize right away as this will help the lid seal properly.

3. I cut 1" off the bottom of the liquid dip tube to avoid sucking up the yeast when I transfer. I this the best way? Would some sort of floating intake be better?

No and yes, respectively.

 

[rconway91]

Unfortunately, the trub from a 4.7 gallon batch in the diameter of a corny keg is going to be deeper than an inch.

Do you think I will still be able to transfer out and discard the first bit of trub or will I likely get clogged? If clogging is likely, should I pull the dip tube and cut shorter (another inch?) after fermentation? Or maybe I could depressurize and remove the spring an valve from the liquid post and blow it out the top?

 

[VikeMan]

Do you think I will still be able to transfer out and discard the first bit of trub or will I likely get clogged?

I can't say exactly how deep the trub is going to be, but I think you will be surprised by just how deep it is.

If clogging is likely, should I pull the dip tube and cut shorter (another inch?) after fermentation?

You could. But I think you'd be flying blind somewhat.

Or maybe I could depressurize and remove the spring an valve from the liquid post and blow it out the top?

I really think there's going to be too much for that to work. Personally, I do closed xfers almost exclusively, but I think in this case I would bite the bullet and rack in a more traditional way (siphon/autosiphon). Or, you mentioned a floating dip tube. If you have one, now would be the time to install it, i.e. while you still have an active fermentation blowing.

 

[rconway91]

After some reading elsewhere on the forum, I went the floating dip tube route. It seems there are a fair number of people that ferment and serve out of the same corny. Seems like an awesome idea if it works out!

 

[Nathan Graen]

How did it turn out? And at what temperature did you ferment?

 

[rconway91]

How did it turn out? And at what temperature did you ferment?

I fermented at room temperature with no temp control, so mid 70s. I fermented for about a week and then put it straight in the fridge. Gave it a couple weeks then tried it.

Its pretty clean, there were some fruity flavors/esters and cloudiness for the first couple weeks, but the last few have been really clean and it keeps getting better. Definitely seems like a lager to me.

 

[VirginiaHops1]

Trying my first pressurized fermentation. I purchased a spunding valve that connects to the gas connect on my pin lock corny keg. I am making a Helles Lager at room temp using Omega Lutra at 15 psi. I have some questions about fermenting in a corny under pressure

1. How much head space do I need? My current batch was 4.7 gal and there has been no sign of blowout getting to the spunding. Is the pressure keeping the krausen down? Could I go more (4.8 - 4.9 gal)?

2. Do I need pressurize the keg right away once I pitch the yeast or can I just wait until until it self pressurizes?

3. I cut 1" off the bottom of the liquid dip tube to avoid sucking up the yeast when I transfer. I this the best way? Would some sort of floating intake be better?

I ferment in kegs. I love it. I think it's improved my beer quality because I can really button up my process and limit DO thx to spunding and closed transfers. The only downside is it is hard to do full 5 gal batches but as you're seeing you can fit a surprising amount of wort in a 5 gal corny without issues, since they really are more like 5.5 gallon vessels.

1. I haven't gone beyond putting 4.5 gal into the keg although I have kept increasing it lately with no problems. Not sure how far I could push it. You can also use fermcap to limit the krausen and possibly squeeze more in although I haven't tried that yet. I have a batch fermenting right where I had 5 gal after boil, and probably put ~4.5 into the keg after leaving behind the trub at the bottom of the kettle. Bubbling away great with kveik voss.
2. On a lot of the older kegs the lid doesn't seat that well without pressure, so I usually pressurize when I close the keg up. Obviously as soon as I attach the blow-off it depressurizes.
3. I think you'll need to either use a floating dip tube or put a filter around the liquid dip tube. I tried the floating one and just found it really finicky for some reason. What I eventually found I liked best was drilling a hole in the top of one of those mesh metal hop canisters and inserting the liquid dip tube into that. I did have to trim the dip tube a bit since it couldn't go all the way to the bottom of the keg. On my dry hop kegs I'll do the canister and also wrap it in a mesh bag, and that works well. I've found just using the canister isn't enough with heavy dry hop loads as that clogs worse than yeast.

 

[VikeMan]

The only downside is it is hard to do full 5 gal batches but as you're seeing you can fit a surprising amount of wort in a 5 gal corny without issues, since they really are more like 5.5 gallon vessels.

FWIW, I believe @doug293cz measured corny kegs to have between 5.3 and 5.35 gallons volume.

 

[doug293cz]

FWIW, I believe @doug293cz measured corny kegs to have between 5.3 and 5.35 gallons volume.

Correct. These were ball lock kegs, don't know how similar pin locks are, since they are a slightly different aspect ratio.

Brew on

 

[cmac62]

I have a few questions: How do you attach the floating dip tube? With the spunding valve, at what pressure do you set it at, or do you use a regular airlock then put the valve on when you want to naturally carb the beer?

 

[VikeMan]

How do you attach the floating dip tube?

The ones I have came with a shortened, replacement beer side dip tube. You install it, and then slip the floating tube's hose over it (inside the keg).

With the spunding valve, at what pressure do you set it at, or do you use a regular airlock then put the valve on when you want to naturally carb the beer?

I don't ferment in kegs, but I do use a spunding valve on my conical, in place of an airlock. I set it to about 2 PSI.

 

[Carolina_Matt]

I ferment in kegs. I set up a blowoff tube for the first ~3 days. I don't install the gas post during this time - I just put a silicone tube over the opening for where the gas post would be installed.

Once the bubbling dies down (about once every second), I remove the blowoff tube and install the gas post. I have my spunding valve set to about 25 PSI, which is the equivalent to about 10 psi @ 38 degrees. By the time fermentation is complete, the beer is fully carbonated.

If you're not serving out of that keg and you want to transfer to a second keg, I'd imagine you wouldn't want to fully carbonate the beer so you'd need a lower psi.

 

[DVCNick]

If you're not serving out of that keg and you want to transfer to a second keg, I'd imagine you wouldn't want to fully carbonate the beer so you'd need a lower psi.

As long as your pressure differential is only a couple psi, you should be good to transfer fully carbed beer... at least, I've never had any problems with it; transferring from one serving keg to another in my case.

I'm in process on my first pressure fermentation now actually. Also a "room temp" lager. I have a Fermentasaurus, and if you are so inclined, it is clear so you can see the internal level and activity; there is so much headspace that you'll never have to worry about a blowoff, and it comes with the floating dip tube setup as part of the pressure kit. I would definitely want this.

In my case I fermented with S-23 at 67 degrees at about 16 psi.

Right after pitching I did bottle-gas it up to 10psi and then let it free rise to the set point from there. My logic is that I was going to leave it warm the whole time, so didn't want to risk off flavors while the pressure was naturally rising from zero. Whether this is a legitimate issue or not, I don't know.

It looked pretty much done at four days; at six days I took a sample and was right at the expected FG so it doesn't appear to have hurt. I'm cold crashing now and will throw some gelatin in the fermenter probably tomorrow morning. Then will keg it this weekend. So far so good.

 

[renstyle]

I ferment in kegs. I set up a blowoff tube for the first ~3 days. I don't install the gas post during this time - I just put a silicone tube over the opening for where the gas post would be installed.

Once the bubbling dies down (about once every second), I remove the blowoff tube and install the gas post.

Have you tried keeping the gas post on and using a QD+tubing? I was considering going this way rather than fully remove the post.

Ease of cleaning in the event of a blow off?

 

[VirginiaHops1]

I have a few questions: How do you attach the floating dip tube? With the spunding valve, at what pressure do you set it at, or do you use a regular airlock then put the valve on when you want to naturally carb the beer?

With spunding I always wait to attach it until day 2-3, and let it ferment normally with a blow-off until then. I use a QD & tubing for my blow-off. Once I attach the spunding valve I'll let it rise to 25-30 psi. I haven't done a pressure ferment start to finish.

 

[Carolina_Matt]

Have you tried keeping the gas post on and using a QD+tubing? I was considering going this way rather than fully remove the post.

Ease of cleaning in the event of a blow off?

I tried that during my first batch or two, but it got messy when the blowoff went through it. I had to take the gas post and QD off to clean them. So after that, I decided to just put the silicon blowoff tube directly onto the keg opening for a few days. Then after bubbling gets slower, I wipe down around the opening and then install the post/QD/Spunding Valve.

I vaguely recall hooking up the spunding valve right from the start, and blowoff went through there. I had to take it all apart and clean out each part of it.

 

[Bottoms_Up]

With spunding I always wait to attach it until day 2-3, and let it ferment normally with a blow-off until then. I use a QD & tubing for my blow-off. Once I attach the spunding valve I'll let it rise to 25-30 psi. I haven't done a pressure ferment start to finish.

This might work well for ales, but my understanding is that lagers require pressure during the early part of fermentation in order to reduce the most amount of esters. Waiting 2-3 days passes the most active part of fermentation.