Pressurized Closed Loop Corny Keg Fermenting

[degivens]

Floating dip tube. Fermented under pressure. 8oz dryhop for 3.5gal. Serving out of the fermentation keg without issue and it’s awesome and so much easier. Beer is noticeably more aromatic than identical recipe done in SS brew bucket / co2 transfer to serving keg method I did previously.

 

[schematix]

I’m getting the feeling from a lot of places that floating dip tubes are a really good solution to many problems....

 

[duelerx]

I'm using the fermentasaurus floating dip tubes in my kegs (and 2 CB with filters) and they work great. As for filters, I think the main purpose of the filter for the CB is for whole hops as they float...pellets will drop so I free hop in the keg for both floating dip tubes.

I also bought a fermentasaurus fd to use in my keg, but the silicon tube is thinner than the gas dip tube i would like to use on the out post. Did you use the same silicon tube?

 

[leesmith]

I’m getting the feeling from a lot of places that floating dip tubes are a really good solution to many problems....

I get the feeling though that it’s about process. My guess would be if someone dry hops with pellets in primary and plans to transfer with a few gravity points left that the dry hop would still be in suspension potentially causing a clog. Yet to see reports of a floating dip tube clogged but most seem to be used in the SV....which allows time and temp to drop everything out.

 

[cheesebach]

I used the screen over the dip tube described here in my last NEIPA:

http://scottjanish.com/my-favorite-way-to-dry-hop-loose-in-primary-and-kegs/

I spunded to naturally carbonate at the end of fermentation and used the closed gravity transfer method from this thread. Transfer went smoothly without removing poppets and it was definitely the cleanest looking 1st pour from the serving keg of any dry hopped beer I've done. I'd say it worked pretty well:

 

[leesmith]

I used the screen over the dip tube described here in my last NEIPA:

http://scottjanish.com/my-favorite-way-to-dry-hop-loose-in-primary-and-kegs/

I spunded to naturally carbonate at the end of fermentation and used the closed gravity transfer method from this thread. Transfer went smoothly without removing poppets and it was definitely the cleanest looking 1st pour from the serving keg of any dry hopped beer I've done. I'd say it worked pretty well:

So did you carbonate, chill, and then transfer to SV?

 

[hezagenius]

Floating dip tube. Fermented under pressure. 8oz dryhop for 3.5gal. Serving out of the fermentation keg without issue and it’s awesome and so much easier. Beer is noticeably more aromatic than identical recipe done in SS brew bucket / co2 transfer to serving keg method I did previously.

This has been my plan on my next brew. Serve directly from the FV (pony keg). I figure I will open the FV once around day 2 to dry hop. I'll purge the heck out of it, set the spunding valve to 15-20psi, and not open it again until the keg has kicked. I've always noticed the sample when I rack to my serving keg is usually off the charts insane but when I tap my keg after carbonating, it has lost something. I want to see if this will make a difference. I will be using 2 SS mesh screens around the diptube and have the diptube rest about 1" above the bottom of the keg. The opening is too small to get a floating diptube in there I think. Now I just need to find the time to brew!

 

[vtipsy]

I get the feeling though that it’s about process. My guess would be if someone dry hops with pellets in primary and plans to transfer with a few gravity points left that the dry hop would still be in suspension potentially causing a clog. Yet to see reports of a floating dip tube clogged but most seem to be used in the SV....which allows time and temp to drop everything out.

I do exactly this now. Ferment in FV with a clear beer floating tip tube (with the filter), dry hop with loose pellets and transfer to SV with a few points remaining to spund. I've had one clog out of maybe 5 hoppy batches, on the second go, where I think (maybe) the tubing dislodged from the float. That was a royal PITA.

The filter is essential because some lighter hop material will definitely still be floating.

 

[cheesebach]

So did you carbonate by spunding, chill, and then transfer to SV?

My typical process is to use a blow-off tube until the 1st dry hop, then switch to spunding at low pressure (2-3psi) for the next 1-2 days. Then, I'll allow the pressure to rise up to ~23psi while it finishes out. A day or two before kegging, I'll remove the spunding valve and drop the temp of the fermentation freezer down to 40F to help crash out some of the hops and yeast before transfer. I'm sure I could probably skip that with this setup without clogs if I were in a rush, but I feel like the short cold crash helps the yeast settle a bit so worth it to me if I have the time.

 

[stickyfinger]

I assume that when people serve these beers from the keezer, you use a CO2 cylinder to provide the head pressure and that the oxygen in the cylinder is not enough to severely damage the beer over the few months it is being served? Or, are you pushing CO2 into the head space from a fermenting beer somehow to insure there is no oxygen getting into the keg when serving?

 

[thekraken]

I assume that when people serve these beers from the keezer, you use a CO2 cylinder to provide the head pressure and that the oxygen in the cylinder is not enough to severely damage the beer over the few months it is being served? Or, are you pushing CO2 into the head space from a fermenting beer somehow to insure there is no oxygen getting into the keg when serving?

I think it takes about 1.5x more gas to carbonate a corny than it does to serve it. Or in other words if you're naturally carbonating your theoretically exposing your brew to 60% less (trace) oxygen than if you were force carbing... I think

http://www.homebrewfinds.com/2014/09/kegging-co2-use-estimations-and-calculations.html

 

[vtipsy]

I assume that when people serve these beers from the keezer, you use a CO2 cylinder to provide the head pressure and that the oxygen in the cylinder is not enough to severely damage the beer over the few months it is being served? Or, are you pushing CO2 into the head space from a fermenting beer somehow to insure there is no oxygen getting into the keg when serving?

Yeah basically, you take the hit. However, the floating dip tube comes to the rescue as beer that is exposed to oxygen in the headspace will be the first to be dispensed.

 

[stickyfinger]

What pressure would you need to start with in a fermentation-purged corney keg to serve an entire 5G corney of beer such that the ending pressure is around 12psi in each vessel?

 

[stickyfinger]

What pressure would you need to start with in a fermentation-purged corney keg to serve an entire 5G corney of beer such that the ending pressure is around 12psi in each vessel?

I tried using the ideal gas law, but I probably made a mistake. I think you'd need a minimum of 26 PSI at 75F in a 5G corny in order to serve 5G of beer at 12PSI at 38F. Could you pressurize a corny to around 30 PSI using fermentation gas from another fermentation and use that to serve the batch you really want to protect from oxygen, like an NEIPA?

EDIT: Indeed, I did make a mistake, plugging in psig in place of psi to the calcuation. I think it should be closer to 41 PSI required to serve an entire keg.

 

[Hannabrew]

I tried using the ideal gas law, but I probably made a mistake. I think you'd need a minimum of 26 PSI at 75F in a 5G corny in order to serve 5G of beer at 12PSI at 38F. Could you pressurize a corny to around 30 PSI using fermentation gas from another fermentation and use that to serve the batch you really want to protect from oxygen, like an NEIPA?

You probably could but I think you'd be fine pushing with co2 for the month or so the keg would last as long as you're keeping o2 everywhere else.

 

[TimmyWit]

I’m getting the feeling from a lot of places that floating dip tubes are a really good solution to many problems....

I just started using them recently and I'm a fan. I ordered 2 and after pouring a relatively clear gravity sample 48 hours into fermentation, I ordered 8 more. These 2 pictures show what remained after a couple counter-pressure transfers. I was able to move nearly every drop and all that was left is a nice little cake on the bottom for me to pitch on.

 

[chieftain]

I do exactly this now. Ferment in FV with a clear beer floating tip tube (with the filter), dry hop with loose pellets and transfer to SV with a few points remaining to spund. I've had one clog out of maybe 5 hoppy batches, on the second go, where I think (maybe) the tubing dislodged from the float. That was a royal PITA.

The filter is essential because some lighter hop material will definitely still be floating.

Do you purge the serving keg before the transfer, or nah? I figure the remaining yeast will generate enough C02 to push out the oxygen in an unpurged keg but wanted to confirm.

 

[stickyfinger]

Do you purge the serving keg before the transfer, or nah? I figure the remaining yeast will generate enough C02 to push out the oxygen in an unpurged keg but wanted to confirm.

ha ha ha. do these guys purge? you have some reading to do my friend!

 

[chieftain]

ha ha ha. do these guys purge? you have some reading to do my friend!

I know, total brainfart on my part. Forgot which thread I was responding to. I shall purge with vengeance.

 

[Hannabrew]

For those purging I highly recommend fermentation purging...much easier than water purging and you could do more than one keg with a single mid-gravity fermentation

 

[vtipsy]

Do you purge the serving keg before the transfer, or nah? I figure the remaining yeast will generate enough C02 to push out the oxygen in an unpurged keg but wanted to confirm.

It's not a silly question.

There is a fantastic post by doug293cz that wowed us with some maths, if you haven't seen it its here https://www.homebrewtalk.com/forum/threads/keg-purging-with-active-fermentation.628658/

Taking the same initial assumptions he did and adding further that
- You spund with 1 Plato of extract remaining.
- Head space after filling the spunding keg is 1 L of air (210000 ppm oxygen)

1 Plato is 1% sugar by weight. Thats 0.2016 kg of sugar, 0.1037 kg of C02 after its fermented. Thats 51.850 L or 518,500 little bubbles.

Plugging that into his final formula gives:
Final O2 Conc = 210000 ppm * ((1 L - 0.0001 L) / 1 L)^518500 = 6.352e-18 ppm

That's nothing.

You'll dissolve some oxygen as you transfer into the spunding keg and as Hannabrew just said it's really easy to purge with fermentation so that's what I do.

* I've had a few beers tonight so apologies if I made a mistake (do your own calculations - don't trust weirdos on the internet).

 

[stickyfinger]

How do people filter the end of the fermentasaurus floating dip tube? Do you have part numbers and suppliers for the filter you used? I am interested in trying serving an IPA from the primary after having spunded it and will need a to filter out any residual hops and trub after the cold crash if using one of these floating dip tubes.

 

[Hannabrew]

I do not filter and haven't really had an issue

 

[stickyfinger]

I do not filter and haven't really had an issue

Well, I had assumed that I would want to take some samples out of the primary to check gravity or carbonation and such and would need a filter since there will likely be hops floating on top of the beer right? I guess if I just don't take any samples after dry hopping I might be ok without one.

 

[Hannabrew]

Sorry I didn't realize you were talking about using them in primary. I only use them for serving kegs

 

[stickyfinger]

Sorry I didn't realize you were talking about using them in primary. I only use them for serving kegs

well, if i try serving from the primary, the primary will be the serving keg, so i figured I'd need to put the floating dip tube on right from the getgo.

 

[stickyfinger]

I have one of these autosiphon screens. It's a little over 21" long and would fit around my dip tube in a keg:

http://arborfab.com/Auto-Siphon-Filter_p_57.html

Do you think I could just ferment in a 5G corny keg with one of these around the dip tube and then carefully dry hop so that no hops get inside of the screen and serve out of the keg? Do you think it would clog? I think it might work well.

 

[cheesebach]

I have one of these autosiphon screens. It's a little over 21" long and would fit around my dip tube in a keg:

http://arborfab.com/Auto-Siphon-Filter_p_57.html

Do you think I could just ferment in a 5G corny keg with one of these around the dip tube and then carefully dry hop so that no hops get inside of the screen and serve out of the keg? Do you think it would clog? I think it might work well.

I can't imagine how it would clog - if you look at the picture I posted in post #245 there's very little hop material on the screen above the hop/trub line after a brief cold crash and transferring out of the fermentation keg. All the beer that's above the mass of hops at the bottom is just going to flow inside the screen and get sucked up through the dip tube. I do have the bottom of my dip tube sitting 1" above the bottom of the keg to avoid picking up any yeast that may settle inside during fermentation.

 

[chieftain]

It's not a silly question.

There is a fantastic post by doug293cz that wowed us with some maths, if you haven't seen it its here https://www.homebrewtalk.com/forum/threads/keg-purging-with-active-fermentation.628658/

Taking the same initial assumptions he did and adding further that
- You spund with 1 Plato of extract remaining.
- Head space after filling the spunding keg is 1 L of air (210000 ppm oxygen)

1 Plato is 1% sugar by weight. Thats 0.2016 kg of sugar, 0.1037 kg of C02 after its fermented. Thats 51.850 L or 518,500 little bubbles.

Plugging that into his final formula gives:
Final O2 Conc = 210000 ppm * ((1 L - 0.0001 L) / 1 L)^518500 = 6.352e-18 ppm

That's nothing.

You'll dissolve some oxygen as you transfer into the spunding keg and as Hannabrew just said it's really easy to purge with fermentation so that's what I do.

* I've had a few beers tonight so apologies if I made a mistake (do your own calculations - don't trust weirdos on the internet).

I had trouble following your math this morning, sober, so I think you did a pretty great job laying it out. Thanks for the links and tips. Will report back on how it goes.

 

[Veets]

What do you guys think about this idea for dryhopping:
Use a floating dip tube in the fermenting keg, and suspend a mesh bag containing a few oz. of hop pellets up in the corny lid, as high as possible. Use a release mechanism, maybe something magnetic, or rigged for a quick tug on the PRV, to drop the bag full of hops into the almost-finished beer, prior to transfer, and without opening the keg. Think it would work? Would it make a difference?
I suppose the same idea could be applied to the serving keg - rig them up in there and let them get flushed with CO2 from the fermenting vessel, keep things closed up, and then drop them in after transfer, without opening the keg.