Closed pressure transfer from a plastic fermentation bucket

[mac.cartier]

Hey all, I am just getting into kegging and I’m brainstorming ways to perform a closed transfer from my plastic fermentation bucket to a keg. I don’t have a ton of space so using one of my kegs to ferment will limit my batch size and how many beers I can have on tap at a time.

I purchased some gamma seal lids which claim to be airtight so that I can watch the bubbler bubble. I am hoping to be able to use the airlock fitting/hole to apply a few PSI of CO2 and push the beer out another access port in the lid.

I think this is feasible, the beer would need to travel at most 15” up a tube/cane.
Using the hydrostatic pressure formula P = ρ*g*h, with ρ = 1050 kg*m^-3, g = 9.31 m*s^-2, and h = 0.381 m, we get a pressure of 3850 Pa or 0.56 psi. I’m reasonably confident that the lid will be able to hold 1 psi for a few minutes.

For fittings, I am thinking that the CO2 inlet could be a ball-lock post, a MFL connector, or just a hole with a grommet that will accommodate some tubing. The liquid outlet could be any of these three but there is the question of whether I want to use a fixed dip tube or if I want to stick a racking cane in there to accommodate different levels of trub. I’m an apartment brewer so I do relatively small batches (1 - 2.5 gal). Because of this I want to waste as little beer as possible when transferring. I thought about just adding a spout on the side of the bucket but that seems pretty inflexible in terms of trub level and I would really like the buckets to be stackable.

Any thoughts? Have any of you tried this?

 

[Broken Crow]

Here's probably the simplest solution:
https://www.brewhardware.com/product_p/balllockbulk_floatingdiptube.htm
Welcome to HBT!

 

[mac_1103]

Any thoughts? Have any of you tried this?

An HDPE bucket fermenter certainly can handle a coupe of PSI, but be aware that many cheap regulators might not be accurate at 1 or 2 PSI. If you're going to go to all the trouble of adding two ports to the lid, you might as well attach a floating dip tube to one of them. There's a long thread on modifying a Fermonster to do low pressure closed transfers. The basic principle is the same.

Because of this I want to waste as little beer as possible when transferring. I thought about just adding a spout on the side of the bucket but that seems pretty inflexible in terms of trub level and I would really like the buckets to be stackable.

IMO, a gravity closed loop transfer through a spigot is by far the simplest way to minimize oxygen exposure when moving beer from a bucket to a keg. The keg needs to be purged first of course, either with fermentation gas or by pushing water or sanitizer out with bottled CO2. Prop up the bucket under the spigot during fermentation so the trub collects on the other side. I usually put 5.5 gallons of wort into the fermenter and have no trouble filling a keg without trub. If you don't want to waste the little bit that's left you can carbonate it in a used PET soda bottle. The buckets will still be stackable if you remove the spigots, which you should do for cleaning between brews anyway.

 

[Brewer Mike]

You could add a spigot. Have a tube with a liquid ball lock go from the spigot to the liquid post (have the bucket higher than the keg). Have a gas ball lock go from the gas post to the hole for the air lock, and let gravity allow the flow, with the CO2 from the (presumably) purged keg going into the bucket.

 

[Closet Fermenter]

Gravity is your friend, especially since you are doing small batches and not having to deal with heavy lifting. I use stainless fermenters (without spigots) and still use gravity. They are not pressure vessels, so even they don’t hold much pressure, but fortunately, just enough to get a siphon going.

I like the weldless post and floating dip tube option suggested above; hopefully the gamma lid can handle enough to initiate a siphon. I had considered adding spigots to my fermenters, but fear of leaks, accidental opening, and possible infection caused me to decide against it.

Also, remember, the gravity is free; you have to buy the co2 to push the beer with pressure.

 

[redrocker652002]

I am going with what was already said. I use a plastic bucket with a spigot at the bottom. I got it from Northern Brewer along with all the other stuff from the starter kit. I fill the keg with starsan and water and push the liquid thru my tap to sanitize it. When done, I move the sterilized keg full of CO2 to the garage and put the bucket on the washer. Put the keg on the floor, add a line from the spigot to the out post of the keg, where I have a floating dip tube. Open the PRV on the keg (if I don't, the pressure from the keg causes the beer to shoot out from the pressure relieve on the spigot), open the spigot and let gravity do it's thing. I cannot say it is perfect, but it seems to be working for me. I have a bit of trub at the bottom, but usually it does not add up to much. I transfer as much as I can into the keg and let whatever gets in there settle to the bottom.

 

[mac.cartier]

Awesome, thanks all for your suggestions, I’m going to start playing around with the gamma lids and a dip tube to see if I can get a healthy siphon going. Do you know of any good ball-lock airlocks? I suppose I can just use a bit of tubing and a glass of sanitizer…

 

[Tony B]

I sterilized the air hose and just pushed it into the hole in the lid of the bucket. Was a tight enough fit that when I pulled it out midway though the transfer, I heard a little whoosh of co2 coming out.
I may eventually buy a bulkhead type gas post and install it in the lid, but for now, this works.

 

[Broken Crow]

Awesome, thanks all for your suggestions, I’m going to start playing around with the gamma lids and a dip tube to see if I can get a healthy siphon going. Do you know of any good ball-lock airlocks? I suppose I can just use a bit of tubing and a glass of sanitizer…

I'm not entirely clear on what you mean.... If you mean you're going to buy and install the floating diptube/closed transfer kit I linked to ( https://www.brewhardware.com/product_p/balllockbulk_floatingdiptube.htm ) Then yes; Just plug a gas disconnect in with a hose into a jar of sanitzer. I haven't used bucket myself, but from what I've read on here of Gamma lids, they provide a good seal that'll allow a few psi of pressure adequate for fermenting and transfering. If you are going that route, then there is essentially no difference in using a bucket rather than a Fermonster and @Dgallo 's excellent thread; https://www.homebrewtalk.com/thread...lete-closed-transfer-system-for-cheap.680992/ which @mac_1103 linked to can answer many questions you may have and I highly recommend giving it a read.
Keep us updated on how you decide to proceed.

 

[mac.cartier]

In the spirit of experimentation I got some bulkhead ball-lock posts and installed them in the lid along with a floating dip tube.

I transferred a few gallons of water with gas without any serious issues. I went up to ~2 psi and found CO2 leaking out of these divots which I presume are there to vent excess pressure in a semi-controlled manner, but it didn’t stop liquid from transferring.

The biggest problem was that the bottom of the bucket started bulging as soon as any meaningful pressure was applied. It’s probably not great for the bucket but I don’t think it’ll bust or tip over like one of these guys.

I was also able to start a siphon with the gas so extended time with a bulging bottom won’t be a big concern. I’m excited to start using these for my IPAs!