Closed transfer stuck with a gallon left in FV

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ILMSTMF

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Fermzilla All Rounder. A gallon remains in it and foam has filled the transfer hose. Up until that point, a combination of spunding valve and pulling keg PRV were used to keep the transfer moving.

• I tried combinations of depressurizing FV and keg. Nothing got it moving.
• Using the pressure transfer kit with the filter attachment. The filter appears to be sitting under the surface of the beer.
• 5 psi from the CO2 tank.

Assumption - the beer is over carbonated. During dry hop contact, airlock was not connected. ~20psi built into the tank. I do this to get some "free gas" for the cold crash that follows. That way, the FV doesn't implode.

Currently, the FV is sitting with the PRV open. My hope being that will allow CO2 to come out of the beer. I won't be surprised if I'm wrong.

I'd like to get that last gallon into the keg...ANY advice is welcome, thank you!

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Gnomebrewer

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Also, when you transfer, you really need to keep the receiving keg at or around the same pressure the fermzilla was at during the ferment. This will prevent foaming in the keg, and is made easier with a spunding valve. Of course, to keep the flow, the fermzilla has to be at a higher pressure (preferably at least a few PSI higher). If I have a beer in fermenter at 26PSI, I pressurise the receiving keg to 26PSI then push the beer out at 30PSI.
 

IslandLizard

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Perhaps the filter has clogged up? I get that with my homemade racking filter at times, and it stalls the transfer.

Or the floating racking filter/tube has lost its "prime," not being underneath the beer level anymore. So it's blowing bubbles (foam).
Is the inside racking hose still slack or is it lifted up the filter/tube?
 
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ILMSTMF

ILMSTMF

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Impatience prevailed, yet again. I got most of what I could out of the FV before getting intermittent blasts of gas in the tube / foam exploding out of the spunding valve. The method was to add ~7psi to FV then attach the jumper hose to FV and keg. Before, the pressure was set to ~5psi. Gave up with "who knows how much" beer left in FV. Here's why...

When I returned to the FV after leaving its PRV open, a very prominent krauszen bubbled up. I've seen that happen before... when releasing pressure from FV before opening the lid for a dry hop charge.

Anyway. Keg weighs 45.5# which is about 5# shy of what I'd normally be filled to. Not stressing it.

It could be that the liquid tube on the fermzilla or receiving keg is blocked. Try blowing some CO2 through both to clear them.
Yup! I tried that before starting this thread. Using a jumper to connect the gas QD to one of the liquid QD on the jumper hose. Blew some out of the hose and reattached FV to keg, no luck.

Perhaps the filter has clogged up? I get that with my homemade racking filter at times, and it stalls the transfer.

Or the floating racking filter/tube has lost its "prime," not being underneath the beer level anymore. So it's blowing bubbles (foam).
Is the inside racking hose still slack or is it lifted up the filter/tube?
I couldn't say. Wish I had an answer for both. The krauszen got thick so who the knows where the filter / floating dip tube wound up. But! I wound up getting the transfer going again so that's all that matters, I suppose.

Thanks!
 

micraftbeer

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It looks like you're trying to gravity transfer a pressurized beer. I've never tried that, perhaps it would work on a combination of principles.

1. As said above, do not de pressurize your FV.

2. Fill your keg with pressure to slightly below your FV.

3. As you gravity transfer, your head pressure in FV will gradually get lower, so you'll need to with decrease sounding pressure on your keg to keep flow going, it maybe you can manage this with short bursts of PRV release.
 

jerrylotto

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Yes I'm gravity transferring but do you not see the pressure equalization line going back up to the conical fermenter? Any CO2 displaced from the keg, travels up that line and equalizes pressure in the fermenter headspace. Pressure is irrelevant because it's normalized.

In fact, in this photo I still have the air bubbler attached to the top of the fermenter which allowed me to confirm that I wasn't pulling a vacuum there. I usually replace that with a plug.
 

IslandLizard

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IIRC, there's a similar thread from around a year ago with a similar issue. The brewer was doing a closed transfer from a conical (?) in his ferm chamber to a keg on the floor, about 6-12 inches lower. That transfer also stalled prematurely, for "unexplained" reasons.

I'm quite convinced it all has something to do with pressure differences.

That said, I've successfully transferred ("jumped") beer from one keg to another, under pressure, standing side by side. All without a spunding valve, just releasing excess pressure periodically when flow was slowing.
 

micraftbeer

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I got the picture confused with the OP's problem. Now I see that @jerrylotto transfers unpressurized beer to the keg via gravity transfer, wheras @ILMSTMF was trying to transfer his pressurized beer into a keg.

In which case I'm back to echoing the above comments: 1) Don't vent the FV, keep it under pressure, 2) Set your keg to the pressure your FV was at the end of fermentation, 3) Apply a higher pressure to your FV via CO2 tank, then connect FV to keg, and modulate keg pressure with spunding.

It sounds like your problem probably occurred when you vented your beer under pressure, and that caused some krausen/foam in your FV. When you got down to 1 gallon left, the foam messed with your floating dip tube and you started sucking foam/headspace CO2.

You may have gotten it restarted when you provided that 7 psi of head pressure and it was able to calm down the krausen.
 
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ILMSTMF

ILMSTMF

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Stylizing the important notes, responding to red text.

You simply cannot vent the FV at all once the pressure and carbonation stabilizes. If you get to 15psi, you have to keep feeding the fermenter about 15-18psi as you transfer out. You also need a spunding on the receiving keg set at 15 exactly.
I'm quite convinced it all has something to do with pressure differences.

That said, I've successfully transferred ("jumped") beer from one keg to another, under pressure, standing side by side. All without a spunding valve, just releasing excess pressure periodically when flow was slowing.
1) Don't vent the FV, keep it under pressure, 2) Set your keg to the pressure your FV was at the end of fermentation, 3) Apply a higher pressure to your FV via CO2 tank, then connect FV to keg, and modulate keg pressure with spunding.

It sounds like your problem probably occurred when you vented your beer under pressure, and that caused some krausen/foam in your FV. When you got down to 1 gallon left, the foam messed with your floating dip tube and you started sucking foam/headspace CO2.

You may have gotten it restarted when you provided that 7 psi of head pressure and it was able to calm down the krausen.
This could have been a combination* of factors. Up until the point of stalled transfer, only the keg was being vented. I would see bubbles sitting still in the transfer hose. I'd spund to let some pressure out of keg. The bubbles would move (with beer [duh]) into keg.
*Anyway, what combination am I referring to? After transferring what I could, I let the FV crash overnight. Looked into the FV through the trub-laden wall and it appeared that the dip tube / filter were above the beer line.
It was a dumb idea to release FV pressure. It was a dumber idea to continue transfer after doing that. Even though "stuff" was covering the filter allowing for a transfer to continue, you all probably know that I was pulling in yeast. Negating the cold crash efforts. In glass, it's a bit cloudy. The first few pours had sediment but perhaps it's clearing up with a little time.
TMI alert lol - usually consuming beer with a lot of noticeable yeast hanging out does a number on my insides. Glad to report that I have not succumbed to illness! So, who the FK knows?

Thanks all!
 
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ILMSTMF

ILMSTMF

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But, of course, I don't want to repeat failure.

If you get to 15psi, you have to keep feeding the fermenter about 15-18psi as you transfer out.
Set your keg to the pressure your FV was at the end of fermentation,
My friends, how do I know what that pressure value is (or is it was) in the FV? Buckle up for another one of my wordy rides filled with overthinking at every turn!

During dry hop contact, airlock was not connected. ~20psi built into the tank. I do this to get some "free gas" for the cold crash that follows. That way, the FV doesn't implode.
That pressure built up pretty early. Like, 2 days after adding those hops. Vented the FV down to 0. 2 days later, ~20 psi was built up in there again. I only know that based on the spunding valve I left attached to FV, sealed up. *** Worth mentioning that I don't trust the gauge on the spunding valve. ***
So, should I have pressurized the receiving keg to ~18psi in order to transfer? Your advice suggests that! However, with ~5psi of CO2 tank pressure applied to FV... and a spunding valve attached to keg showing 5 and the transfer stopping... (not the end stall with the foaming, described below:)

I would see bubbles sitting still in the transfer hose. I'd spund to let some pressure out of keg. The bubbles would move (with beer [duh]) into keg.
Anyway. how to determine the right pressure to set each vessel to? Put CO2 supply on it and crank it until I hear the tank hum, read value on gauge?

Thanks!
 

micraftbeer

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OK, so here's how I'd do a pressure transfer if I had a spunding valve with a broken gauge (or a gauge you don't trust is accurate).

1. Cap your FV with spunding valve set to X psi. Do not vent this down to 0 psi.
2. When ready to transfer, fill your keg with pressurized CO2 from your tank. Keep dialing up the pressure on your CO2 tank regulator until you think you're at "some pressure higher than X".
3. Move your spunding valve from FV to keg. If you are indeed at a higher pressure, you should hear air hiss out of your spunding valve until it bleeds your keg down to the same X psi.
4. Hook up your liquid transfer line from FV to keg, with spunding valve still on your keg.
5. Adjust the pressure down on your spunding valve until you start to hear air hiss out of your keg through the spunding valve. Your rate of beer flow from FV to keg will be related to how much you lower your spunding valve. Since you have a broken gauge, there's no useful info to give you like "2-5 psi below your FV pressure". So you'll just have to wing it. Since you're fermenting in an All Rounder, you'll be able to see the rate of beer flow. If it's going too slow, adjust the spunding on the keg to lower its pressure. If it's going to fast, dial it back some (but make sure you still hear the hiss of pressure bleeding off as liquid is filling up in your keg).
 
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ILMSTMF

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Now we're talking!!

So you'll just have to wing it. Since you're fermenting in an All Rounder, you'll be able to see the rate of beer flow. If it's going too slow, adjust the spunding on the keg to lower its pressure. If it's going to fast, dial it back some (but make sure you still hear the hiss of pressure bleeding off as liquid is filling up in your keg).
This reminds me of @IslandLizard's method. Every so often, pull PRV of the keg to let the transfer resume.

But that's it yo. I've sort of been following this method all along. However, I like the tip to have the spunding valve do the work. That's the whole damn point of it.
Great advice there. I'm going to do that next time I have to transfer, thanks!!

PS - drinking the beer now. That's pretty damn nice! I'm not seeing any sediment either. Sweet.
PPS - did I already mention I changed the location of the floating ball relative to the dip tube filter? During this problematic transfer, I had the dip tube intake closer to beer surface. I changed the position so the next transfer will have the dip tube deeper in the beer well. We'll see how that goes.
 

jerrylotto

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The ideal gas law is PV=nRT. R is a constant and assuming that T is too, if you don't add gas to the FV, so is n so we can approximate that P is proportional to V. If the FV is a closed system with an overall volume of 8 gal containing 5 gal of liquid and you start at 20 psi in the 3 gal of headspace IF you could remove all of the liquid, the pressure in the FV would be 3/8 of 20 psi or roughly 7.5 psi. Since atmospheric pressure is about 14 psi, the transfer would actually stall about 1/2 way as the FV head pressure drops to atmospheric pressure (assuming no gravity assist). You will have to introduce more CO2 to the FV if you want to push all of the liquid out to a pressurized keg.

Note - gauges actually read "overpressure" so my math is off a bit. 20 psi is really 34 psi so terminal would 12 psi, still below atmospheric but you wouldn't stall until you got down to about a gallon of liquid left :)
 
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IslandLizard

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IF you could remove all of the liquid, the pressure in the FV would be 3/8 of 20 psi or roughly 7.5 psi. Since atmospheric pressure is about 14 psi, the transfer would actually stall about 1/2 way as the FV head pressure drops to atmospheric pressure (assuming no gravity assist).
Please, mind, all our vessel pressures are measured above atmospheric. So even halfway during the transfer, the remaining 7.5 psi is above atmospheric. So that's not causing the problem of the stalled transfer here.
 

jerrylotto

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Please, mind, all our vessel pressures are measured above atmospheric. So even halfway during the transfer, the remaining 7.5 psi is above atmospheric. So that's not causing the problem of the stalled transfer here.
I realized that error and corrected my math by editing the original post. Still drops below atmospheric.
 

jerrylotto

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Did another little back of the envelope calculation using the ideal gas law to figure out how much CO2 is needed to prevent a vacuum condition for cold crashing in a keg. Turns out that a drop from 75F to 32F in a constant volume is less than a 10% contraction of gas (pressure drop) so less than 2 psi (hint - you need to express temperature in degrees Kelvin). If you can pressurize a keg to at least 5 psi over atmospheric you would be good to go.

However, for that temp range, solubility of CO2 goes up from 7 cc/g to 30 cc/g. Of course, then you have to know the volume of headspace to account for dissolution too.
 
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jfowler1

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Timely thread. I had questions about a closed transfer a few weeks back, got some good advice, and stopped in by Bobby’s shop yesterday to pick up the last fittings I needed. I ran two water tests tonight, and it was an awesome success.

I am using a Speidel that is elevated enough to gravity feed into a keg. I have NorCal adapters attached - a liquid ball lock fitting where the spout used to be, and a gas ball lock/prv fitting where the air lock used to be.

I ran a short liquid/liquid tube from the bottom of the Speidel to the liquid out on the keg, and a 3’ gas/gas tube from the top of the Speidel to the gas in on the keg.

Here is how it worked… order of operations for the connections is important.

I put about 6 gallons of water into the Speidel. I pressurized the keg. I then connected the two gas posts. The pressurized keg sent CO2 into the Speidel, and the PRV on top of the Speidel would relief pressure as soon as the fermentor exceeded 5 psi. After about 10 seconds, the PRV stopped blowing off. Regardless of where the PRV was set (NorCal lists it at 5 psi) the pressure between the two vessels was exactly balanced. Then I connected liquid/liquid line. Nothing seemed to happen. I gave a 1/2 second pull to the relief valve on the keg, and liquid started to flow.

That was it… the fermentor drained to keg in about 12 minutes. It seemed to stop when the water going into in the keg hit the gas post inside. I disconnected everything, and tapped both relief valves, and both vessels were still pressurized.

I know this wasn’t a beer transfer, but it was as close as I could get for a test. No spunding valve, no CO2 tank, no baby sitting or constant purging. Outside of that initial tiny pressure release from the keg, this loop was completely closed.

A couple pics:
 

DuncB

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Gravity does help the pressure transfer ie the fermenter higher than the keg.

Short circuit brewers have a good video of how to do it.

Keep the pressure in keg a couple of psi below the ferment pressure and you won't get foam .

After you finish you can always reconnect gas to gas and get a few free psi out of the fermenter or even use that gas for your first pint or two.

Finally I'd say it's a much slower process than I anticipated, takes me at least half an hour to fill the keg. Set a timer, use some scales to check the filling and also watch the condensation line or use a flir camera.
flir_20210509T103302.jpgflir_20210504T203044.jpg
 

jerrylotto

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All you need to speed it up is a greater height difference. Throw a platform jack under the fermenter so once the transfer has started you can raise it up a bit.
 
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