Slim 1/4BB Keg fermenter conversion

[zman_]

Hey all,

I just wanted to lay down the basics of a project I am undertaking and hopefully solicit some help/advice. After seeing some of the cool fermenters/etc that are out there, I got it into my head that I wanted a pair of stainless fermenters for 5 gallon batches. Rather than buying something premade like the brewbuckets or Chapmann fermenters (Although if their pretty great deal was going on when I started this project, I probably would've got two), I decided to make my own.

The base vessels are slim 1/4bbl sanke kegs, ordered brand new from Gopher Kegs (tried to source some from Craigslist with no luck). The plan is to weld a 4" TC ferrule (sourced from brewershardware) onto the bottom of the keg, in order to allow a custom TC blank to be fitted on it and allow easier manual access for inspection/cleaning. A 2" TC clamp/blank/gasket will be used to block off the already-installed stem on the top (now bottom) of the keg.

Currently the kegs are at a local welding shop to have the 4" holes cut and the ferrules welded on. I am working on the plans and ordering parts of the customized lids. I am planning to drill/tap a series of NPT holes to allow for easy installation/cleaning/flexbility in the fittings. Here is a list of what I am planning for the lids:

• 1/4" or 1/2" MNTP Thermowell (Likely 10")
• 1/4" MNTP to ball lock keg post (Gas) +/- gas dip tube (Not sure if I need it)
• 1/4" MNTP to ball lock keg post (liquid) + liquid dip tube
• 1/4" MNTP 40PSI pressure release valve

This will give me the flexibility to ferment as normal, under pressure, naturally carbonate beer off the last few gravity points during fermentation, perform closed transfers between the fermenter & serving kegs, or even serve up to ~7.75 gallons of beer from this keg.

I have a few questions/things I was hoping you guys might be able to help me with:

• Any suggestions for sources for stainless fittings? I have been looking at brewhardware, brewershardware, and bargainfittings mainly, just wanted to know if there are any other places I should be checking.
• Does anybody have experience with the NPT threaded keg posts? I am wondering what size liquid dip tube I would be able to put in there (aka: can I use a standard corny dip tube or do I have to fabricate one out of stainless to fit).
• Any suggestions for fittings that I may not have thought of?

 

[Bluesfastduce]

I use something similar for fermenting. I don't serve out of it. Here is what I added to the top of my 4 inch tc. I got all my fittings from a local pluming supply house here. Maybe you have something like that in your area.

 

[zman_]

Serving is pretty low on the list of things I want to do with it, so I might knock that off the list if it makes getting everything hooked up easier. Thanks for the picture, it is really helpful. From what I can see it looks like you have:

• Pressure release valve. Is it 1/4" NPT or 1/2"?
• Stainless racking cane with NPT compression fittings on both ends connecting to ball valve/keg? What diameter racking cane did you use? and length?
• Mini ball valve + 1/4" flare fitting to connect blowoff/spunding/etc?

Any additional info about what sized fittings you used would be greatly appreciated!

EDIT: Also, are those O-ringed compression fittings? or ferruled? I've seen both on various brew websites and just wondering what works for you.

 

[Bluesfastduce]

Serving is pretty low on the list of things I want to do with it, so I might knock that off the list if it makes getting everything hooked up easier. Thanks for the picture, it is really helpful. From what I can see it looks like you have:

• Pressure release valve. Is it 1/4" NPT or 1/2"?1/4 npt and 50 psi.
• Stainless racking cane with NPT compression fittings on both ends connecting to ball valve/keg? What diameter racking cane did you use? and length? it's 3/8 tube it's a bulkhead fitting the dip tube is about an inch from the bottom I think was around 17 inch. The ball valve and comp fitting are 3/8 also. I use a 3/8 hose barb fitting to transfer to other kegs.
• Mini ball valve + 1/4" flare fitting to connect blowoff/spunding/etc? Yep and to pressure transfer.

Any additional info about what sized fittings you used would be greatly appreciated!

They also have a 1.5 tc on the side that I added a 3/8 thermal well to

 

[justhookittomyveins]

Beautiful build. I've got a few questions as I'm looking to do the same in the future:
What do you use the 2" TC opening on the (old top) bottom for?
Does the TC fit natively with the original opening?
Did you have to tap the holes in the endcaps for the fittings?
Do you find the keg much easier to clean with a 4" opening?

Many keg fermentor conversions utilize the original opening with a keg washer to clean, so what, in the case of easy cleaning, would be the major benefit of going for 4"TC?

 

[zman_]

Answers to your questions:

I currently just plug the 2" TC opening on the bottom (old top). I have some thoughts about raising the whole fermenter/adding wheels, and using that as a yeast dump/trub dump but they haven't been realized. It is very nice when cleaning the fermenter though, I put it in a sink, take off the 2" Cap on the bottom and just rinse all the trub away in a few seconds.

Sanke necks will take 2" TC caps/clamps as they are the same size (you just have to make sure to center it and keep it centered - this depends a bit on the keg brand). A standard TC gasket doesn't work with a standard sanke neck as there is no groove on the keg side for the lip in the gasket to insert into. The solution is to either 1) buy a half-gasket (some places like brewers hardware and brew hardware sell them I think or 2) Take a hobby knife and shave off the lip on one side (This is what I did, very easy - but I bought a few extra gaskets for backup just in case I destroyed one).

With the help of a friend, I drilled/tapped 4 NPT holes of various sizes in my 4" end cap. I was lucky to have access to the tools/ability to make/tap these holes. If you don't have that access, an alternative would be to get a 4" to 2" TC Cap reducer and then use either the standard 2" sanke fermenting kits or build your own "wand/etc" off a 2" TC x 1/2" NPT Tee fitting.

Having the 4" opening, I don't see how you could reliably clean a post-fermentation keg without it. I love the ability to reach my hand/arm inside the keg and use a sponge/water to make sure that every surface is clean. My normal cleaning regimen for the kegs looks like this: Put in sink, remove 2" TC bottom cap and allow trub to drain. Remove 4" cap/fittings from the top, rinse remaining trub out. Using unscented soap/sponge, clean all inside surfaces of the keg, clean 4" and 2" caps. Rinse all internal surfaces, caps, clamps, etc, and let dry.

The 4" TC isn't necessary by any means but, personally, I gives me peace of mind knowing that the keg is actually clean. Additionally, it makes dry hopping super easy. The downside is that there aren't as many pre-made fittings/etc for 4" TC openings. My next plan is to get a 1/2bbl yeast brink (as I just moved up to 10g batches) with a 1.5"/2" TC ferrule on the side (eventually going to put a rotating racking cane in there), 4" TC fitting on the top, and 4" to 2" cap reducer (eventually going to make/order a few 2" closed transfer apparatuses). $230 shipped for the 1/2bbl, TC-equipped yeast brink with the cap reducer, clamps, and fittings/caps - birthday present to myself when they get back in stock!

 

[justhookittomyveins]

Cheers zman, I talked to a brewer friend of mine, he also seconded the 4" opening, mentioning as you did that getting your hand in there is imperative, specifically for the krausen ring. I still don't know what these keg washers are doing to that hard, caked on stuff. I know when I was using carboys that it took a brush even after soaking all night. I believe I will have to get a tap set if I were to continue, installing reductions just to order premade endcaps is going to break my budget, if the TC route hasn't already.

I'll post my build here when the time comes. Currently waiting on 100L keg quotes.

Oh, and happy birthday!

 

[zman_]

Cheers zman, I talked to a brewer friend of mine, he also seconded the 4" opening, mentioning as you did that getting your hand in there is imperative, specifically for the krausen ring. I still don't know what these keg washers are doing to that hard, caked on stuff. I know when I was using carboys that it took a brush even after soaking all night. I believe I will have to get a tap set if I were to continue, installing reductions just to order premade endcaps is going to break my budget, if the TC route hasn't already.

I'll post my build here when the time comes. Currently waiting on 100L keg quotes.

Oh, and happy birthday!

Thats a pretty massive keg... It might be worth checking with the manufacturer if they can install the 4" TC fitting for you. I know a few places stateside that have the option for triclover ferrules instead of sanke necks (mainly marketed as yeast propagation/storage kegs). That is, unless you're comfortable doing the sanitary weld yourself.

 

[Brickman]

I tried having these made by a couple of local welders and the rate they wanted to charge it was cheaper to have Sabco build me one with the stuff I wanted and still be cheaper than sourcing the parts and have someone weld it for me. Welder wanted $225 for a 4" and 1.5 TC and then with keg and everything else I was well into the $300 range. And if he screwed up the weld I was out the keg. I had Sabco build me one with shipping that was about $270 and it is a German keg with gorgeous welds.

 

[zman_]

I tried having these made by a couple of local welders and the rate they wanted to charge it was cheaper to have Sabco build me one with the stuff I wanted and still be cheaper than sourcing the parts and have someone weld it for me. Welder wanted $225 for a 4" and 1.5 TC and then with keg and everything else I was well into the $300 range. And if he screwed up the weld I was out the keg. I had Sabco build me one with shipping that was about $270 and it is a German keg with gorgeous welds.

I got my kegs for ~$100 each (shipped) from Gopher Kegs (slim 1/4bbl) and then got them sanitary welded by a local person for ~$60 each. If you're looking for 1/2bbl kegs, ABS commercial has the best prices I've found for the 1/2bbl with 1.5" TC and 4" TC, $199 + shipping. SABCO was mid 200s + shipping without any fittings/etc.

 

[Brickman]

I have one of the ABS kegs. My keg is soldered though not welded. Not a huge issue as long as it is sanitary. Also look at Ambrach kegs. They are about the same as Gopher and if they have a local warehouse you save a ton in shipping. I wish I was in a bigger town. I only have one welder and he has a monopoly. I may have to travel to Denver to see if I can get a better rate. I would do $60 for welding in a heartbeat.

Mark