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Attaching a ball lock post to a fermenter at tap level - good/bad idea?

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Toastkid

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I want to try to rig up a closed transfer for my next brew, to avoid pouring it into the keg (which will always add the dreaded O2 into the beer).

I thought that a really simple approach would be to fit a ball lock post at tap level, on the fermenter (which is plastic). Then, I would do the following, when it's ready to be kegged:

1) pump some co2 into the keg (it's a corny keg) at low pressure, and flush it a few times to try to drive out o2 from the keg.
2) connect a line to the post on the keg which sits on the long dip tube (ie the one the beer normally comes out of)
3) connect the other end of that line to the post that's next to the tap on the fermenter

At this point the beer should flow through into the keg. The pressure will build up inside so i will need to keep venting the keg with the release valve.

One potential problem is that as the liquid drains out of the fermenter it will pull in air through the airlock, and although in theory there should be a "blanket" of co2 on top of the liquid, protecting it from the o2, there's bound to be some mixing and some o2 will end up coming into contact with the upper surface of the beer. (However, there might still be some foam on top of the liquid which would act as a barrier too.) To try to prevent that, I thought of fitting a second ball lock post into the lid of the fermenter, and then I can pump some co2 into the fermenter, take the airlock bung off and put in a solid bung instead, and just add co2 into the fermenter to push out the liquid (it will only require atmospheric pressure co2 for this). But, that might be really expensive in terms of co2.

Has anyone here tried something like this? Any general advice? thanks
 

Ben034

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What type of beer are you usually making? I'm sure there a various opinions on when a closed transfer is required. In my mind, it's more important when brewing very highly hopped beers like a NEIPA. If you use a tap or a syphon to transfer from fermenter to keg, there is no need to pour the beer. A tap would be useful if you don't want to syphon, although can be a pain if you get leaks and to ensure it is cleaned each time. Have a search of the forum for "closed transfers" if you really want to limit oxygen exposure. Sorry, not something I have experience with. This article may be a helpful starting point:

 

The-Engineer-That-Brews

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Myself I put a 1/4” push fit bulkhead connector through the lid of the FV. When I’m fermenting I connect a bubbler to it, and when it comes to transfer time I just connect it to the gas line with the regulator set very low. As the output from my regulator is 3/8” pushfit it only takes a minute to swap it over from the ball-lock to a bit of tubing to the FV (and 1/4” tubing fits sufficiently snugly inside 3/8” at such low pressures).
Up to you of course, but I’d say a pushfit connector is a lot cheaper than a ball-lock and personally I’m happier with it fitted above the ‘waterline’
 

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The-Engineer-That-Brews

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Alternately when it comes to doing the closed transfer you can just flood your keg with CO2, then link the gas and liquid ports of the keg and FV and let gravity do the job for you. Beer entering the keg displaces gas from the cylinder which goes back into the headspace of the FV - et voila: closed transfer...

210EEA5C-12F2-49EB-83EA-BAC06DCAEC29.jpeg
 

The-Engineer-That-Brews

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Just re-read your post, and I think you are describing in fact describing a similar setup to the above 👍🏻 but I would suggest it’s still better to connect into the headspace rather than at tap level, otherwise the gas coming back into your FV will be bubbling up through the beer and disturbing the sediment.

The pressure will build up inside so i will need to keep venting the keg with the release valve.
No, there is no pressure build up. It‘s a closed system so the volume of beer leaving the FV and entering the keg is exactly the same as the volume of gas displaced from the keg back into the headspace of the FV. There is no need to pressurise the Corny either - just flush it with CO2... if there’s a little bit of air in there it really doesn’t matter - the main thing is, as you say, not to introduce vast amounts by pouring it in.
 

Toastkid

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Myself I put a 1/4” push fit bulkhead connector through the lid of the FV. When I’m fermenting I connect a bubbler to it, and when it comes to transfer time I just connect it to the gas line with the regulator set very low. As the output from my regulator is 3/8” pushfit it only takes a minute to swap it over from the ball-lock to a bit of tubing to the FV (and 1/4” tubing fits sufficiently snugly inside 3/8” at such low pressures).
Up to you of course, but I’d say a pushfit connector is a lot cheaper than a ball-lock and personally I’m happier with it fitted above the ‘waterline’
After watching a couple of videos I think you're right, this is the way to go. In the closed transfers I watched, they do the following:
- fill the keg with water, to the brim
- pump in co2 to "dispense" out all the water, same as you would do with the beer
- attach the short dip tube connector to the top of the fermenter, like you say
- put a beer line onto the fermenter tap and attach it to the long dip tube connector on the keg

Then as the beer flows into the keg, the excess co2 is pumped back into the keg, and it's a totally closed system, which is basically swapping gas in the keg for liquid in the fermenter.

That is loads easier than what I was thinking of, and doesn't involve adding anything below the waterline, which was making me a bit nervous as well.
 

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This what I’m exbeerimenting with now!


I have taps fitted to the bottom (not side) of my FVs and a float arrangement (from a top tap King Keg) so the beer is drawn from the top and gravity takes it out the bottom, no siphon necessary.

38668FD8-8CFB-4FEF-A5FC-160A808FF21D.jpeg


Hoping to use CO2 from fermentation to push water out of a previously sanitised King Keg which when full of gas can be sealed off until “racking” time. Then GAS IN connection on the King Keg is connected to the FV lid and the FV tap is connected to the BEER OUT connection on the King Keg lid that has a tube and float connected to it on the inside. FV tap is turned on and beer (should) flow out of the FV into the KK and CO2 (should) be displaced from the KK back into the FV through the lid connection. All theory at the moment although I have tested it with water and air. Going to give it a proper test next brew day, hopefully the end of the week, weather permitting :laugh8:.
 

Toastkid

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This what I’m exbeerimenting with now!


I have taps fitted to the bottom (not side) of my FVs and a float arrangement (from a top tap King Keg) so the beer is drawn from the top and gravity takes it out the bottom, no siphon necessary.

View attachment 34334

Hoping to use CO2 from fermentation to push water out of a previously sanitised King Keg which when full of gas can be sealed off until “racking” time. Then GAS IN connection on the King Keg is connected to the FV lid and the FV tap is connected to the BEER OUT connection on the King Keg lid that has a tube and float connected to it on the inside. FV tap is turned on and beer (should) flow out of the FV into the KK and CO2 (should) be displaced from the KK back into the FV through the lid connection. All theory at the moment although I have tested it with water and air. Going to give it a proper test next brew day, hopefully the end of the week, weather permitting :laugh8:.
Interesting. Please let me know how it went!
 

JockyBrewer

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First of all, I think adding posts to the fermenter isn't a great idea. I'd just figure out a way to attach a hose straight to your fermenter tap for the outlet, and you can easily enough attach a balloon with CO2 in it to the airlock.

Having said that, from my experiences with very hoppy beers and kegging so far, I don't think there is much danger from the little bit of air that comes in while transferring from fermenter to keg. The real damage is done when trapping your beer in a keg with air, so that's what you want to avoid, so I highly recommend purging your kegs as you've described.


As for the actual transfer process, the whole circular method you've described where you feed back CO2 from the purged keg into the fermenter should be the ultimate answer, but I've not got it to work in a couple of attempts. The beer just stops flowing. I think the main issue was that for the beers in question (heavily hopped IPAs) you end up with quite a lot of line resistance, and it becomes very very easy to block tubing/disconnect/post with a little bit of hop debris. I suspect with pressure going into the fermenter it would force the debris through, but my fermenter will not hold more than about 1psi.

Last time I did a NEIPA I ended up taking the lid off the (purged) corny keg and just running the beer straight in from the fermenter using a long silicone hose, with the corny lid covering as much of the opening as possible. I ran CO2 in at low pressure through the gas post while doing so. I also cracked open the lid of the fermenter. The result was perfect - not a hint of oxidation over the 6 weeks I drank the beer.
 

Toastkid

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Closed trainsfer - purge kegs with co2 from fermentation.
That's a nice idea from a waste-not-want-not pov but I don't think I could pull it off without buying a load more stuff (eg spunding valve for a start).
 

Toastkid

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First of all, I think adding posts to the fermenter isn't a great idea. I'd just figure out a way to attach a hose straight to your fermenter tap for the outlet, and you can easily enough attach a balloon with CO2 in it to the airlock.

Having said that, from my experiences with very hoppy beers and kegging so far, I don't think there is much danger from the little bit of air that comes in while transferring from fermenter to keg. The real damage is done when trapping your beer in a keg with air, so that's what you want to avoid, so I highly recommend purging your kegs as you've described.


As for the actual transfer process, the whole circular method you've described where you feed back CO2 from the purged keg into the fermenter should be the ultimate answer, but I've not got it to work in a couple of attempts. The beer just stops flowing. I think the main issue was that for the beers in question (heavily hopped IPAs) you end up with quite a lot of line resistance, and it becomes very very easy to block tubing/disconnect/post with a little bit of hop debris. I suspect with pressure going into the fermenter it would force the debris through, but my fermenter will not hold more than about 1psi.

Last time I did a NEIPA I ended up taking the lid off the (purged) corny keg and just running the beer straight in from the fermenter using a long silicone hose, with the corny lid covering as much of the opening as possible. I ran CO2 in at low pressure through the gas post while doing so. I also cracked open the lid of the fermenter. The result was perfect - not a hint of oxidation over the 6 weeks I drank the beer.
That's good to know about the stoppage. I was trying to think of some way I could filter the crap out before it reaches the tap but didn't come up with anything.

I'd wondered if putting the keg up to a relatively high pressure beforehand would help speed up the process. Then the gas in the top of the fermenter would be higher pressure which should force the liquid out more quickly which *might* make any particles more likely to get pushed through into the keg rather than jam up in the ball lock.
 

Toastkid

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First of all, I think adding posts to the fermenter isn't a great idea. I'd just figure out a way to attach a hose straight to your fermenter tap for the outlet, and you can easily enough attach a balloon with CO2 in it to the airlock.

Having said that, from my experiences with very hoppy beers and kegging so far, I don't think there is much danger from the little bit of air that comes in while transferring from fermenter to keg. The real damage is done when trapping your beer in a keg with air, so that's what you want to avoid, so I highly recommend purging your kegs as you've described.


As for the actual transfer process, the whole circular method you've described where you feed back CO2 from the purged keg into the fermenter should be the ultimate answer, but I've not got it to work in a couple of attempts. The beer just stops flowing. I think the main issue was that for the beers in question (heavily hopped IPAs) you end up with quite a lot of line resistance, and it becomes very very easy to block tubing/disconnect/post with a little bit of hop debris. I suspect with pressure going into the fermenter it would force the debris through, but my fermenter will not hold more than about 1psi.

Last time I did a NEIPA I ended up taking the lid off the (purged) corny keg and just running the beer straight in from the fermenter using a long silicone hose, with the corny lid covering as much of the opening as possible. I ran CO2 in at low pressure through the gas post while doing so. I also cracked open the lid of the fermenter. The result was perfect - not a hint of oxidation over the 6 weeks I drank the beer.
That idea about not trying to send the beer in through the ball lock, and just using a hose, with extra co2 flushing, is good, i'll definitely fall back to that if it jams up. Another option could be to unscrew and remove the dip tube ball lock, then remove the dip tube, and put the hose in instead: not much air is going to get round the side of that.
 

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I don't think I could pull it off without buying a load more stuff
Just shove a 3/8" hose into the airlock (they even fit in rubber bungs) with a keg connector on the other end, then have another disconnect keeping the other post open or have the lid a little loose.
 

Toastkid

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Just shove a 3/8" hose into the airlock (they even fit in rubber bungs) with a keg connector on the other end, then have another disconnect keeping the other post open or have the lid a little loose.
Actually the main problem is that I only have one keg, and it's usually got beer in it :) Currently I need to time the end of my fermentation for when my current keg runs out, which isn't always easy, though I will bottle it if there's some left over.
 

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That idea about not trying to send the beer in through the ball lock, and just using a hose, with extra co2 flushing, is good, i'll definitely fall back to that if it jams up. Another option could be to unscrew and remove the dip tube ball lock, then remove the dip tube, and put the hose in instead: not much air is going to get round the side of that.
1/2" silicone tube fits over a keg post nicely, but you need to take the post off and remove the poppet first.

I suspect 3/8" silicone tube would fit over the threads the post are on, but it might pop off easily.
 

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fit a ball lock post at tap level, on the fermenter (which is plastic).
second ball lock post into the lid of the fermenter,
My (limited) experience of using ball lock posts is they take a bit of oomph to connect. Will a plastic FV and lid be robust enough? I use camlock fittings on my FB tap and push fit connector in the lid
 

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My (limited) experience of using ball lock posts is they take a bit of oomph to connect. Will a plastic FV and lid be robust enough? I use camlock fittings on my FB tap and push fit connector in the lid
I'm actually swinging towards just drilling a hole in a fresh bung and putting the hose through that, maybe with a bit of silicone. I think you're right that tightening the ball lock post down onto the screw could easily just shear a hole in the plastic lid. What sort of push fit do you use? One that the 10mm (3/8") beer lines go into? Something like this i guess? JG Speedfit Plastic Push-Fit Equal Couplers 10mm 10 Pack
 

The-Engineer-That-Brews

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I'm actually swinging towards just drilling a hole in a fresh bung and putting the hose through that, maybe with a bit of silicone. I think you're right that tightening the ball lock post down onto the screw could easily just shear a hole in the plastic lid. What sort of push fit do you use? One that the 10mm (3/8") beer lines go into? Something like this i guess? JG Speedfit Plastic Push-Fit Equal Couplers 10mm 10 Pack
I use bulkhead fittings; you can get them in 1/4" or 3/8" (also the metric sizes work fine e.g. 6mm works for 1/4")

Last lot I bought were these ones: 1/4" Push Fit Pipe Fittings for American Fridge and RO Unit Elbow, Tee Piece etc | eBay

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