Buy or Build: 3.5 -4 gallon pressurized conical fermenter

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dekesdad

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I've lurked here forever, it seems like. OK, more like 3 or 4 years.

I want a pressurize-able 'unitank' conical fermenter for my project to experiment with single step fermenting & carbonating. BUT, I want to do 2.5gallon half batches.

I figure (that means I'm completely guessing) I'll need a half gallon to 1.5 gallons of headspace for this since it'll be closed and pressurized. Sound about right?

It doesn't look like anyone makes a conical fermenter smaller than 6.5 gallon..Not that I found anyway. Before I go drop $$ on welder and spend some time frigging with it to weld this up myself: anyone seen smaller pressurized conical fermenters?

Here's another question: if it don't need to be pretty, what would prevent me from brazing it up instead of welding it if I end up DIY to get it built?
 
I haven't seen any small ones for sale either. It seems like there must be something available premade that could be a good start for a welding project, like a big SS funnel welded half of a SS tank, maybe a little keg....

How much pressure do you want this to hold up to? Brazing would likely do the trick, but will never be as strong as a good weld.
 
I haven't seen any small ones for sale either. It seems like there must be something available premade that could be a good start for a welding project, like a big SS funnel welded half of a SS tank, maybe a little keg....

How much pressure do you want this to hold up to? Brazing would likely do the trick, but will never be as strong as a good weld.

Thanks for the reply on this one - barring finding anything already available I was thinking the same thing: using a SS funnel welded to a small SS pot.

To answer your question, I was thinking about 15 PSI might work. I could braze or weld the relief valve of any off-the-shelf pressure cooker right on there since most of those are preset at 15PSI blowoff..

I found a 8 qt SS stockpot in Walmart tonight for under $7. I wandered around in the store with it for a bit and discovered that it marries up pretty nice to the SS 4.5 quart mixing bowl on a Hobart kitchen mixer. The two together is 3.5 gallons right there. So, I'm going shopping around the net tonight for price on replacement Hobart mixing bowl and thinking about that combination for a bit.

Welding of course would be desireable, but to be as shoestring about it as possible, it would be obviously cheaper to go buy a torch at Home Depot and silver braze and then finish grind it than to go buy a welding setup..If it would hold up to being watertight and staying watertight under pressure my wallet would rather braze than weld :eek: I'm really interested in thoughts on this one.
 
If you are planning to do pressure fermenting you want something with more structural integrity than a cheap pot soldered to a mixing bowl. At minimum this seam should be welded and I still would hesitate to put anything over a few psi in it. Even at that, you risk creating a bomb if your pressure relief fails. Why not just use a corny? Yeast collection is more difficult but they are designed to hold 130 psi I believe, way more pressure than the yeast can create before dying off. a corny would be cheaper, easier and its a tried and true pressure fermenting vessel.
 
I think you could be alright with brazing for 15psi. But be perpared for it to start spraying beer from a pin hole in it some where. If not exploding.

I don't know about the pressure cooker blow off. There are some that may work, but not the ones I've used. Often the pressure in regulated by a weight on an orifice. This only works when there is a strong pressure build up. It does not hold existing pressure in all that well. It would work during fast fermentation, but the pressure would leak out when things slow down.
The safty values on pressure cookers are often a bit for rubber which will just blow out, the purpous being; it will blow out before the pot blows up. Not an exact pressure, just an intended weakest spot.

There are better pressure regulators available. Ones on Cornie kegs work I've heard, and I'm sure you can get them online for a reasonable price.
 
im sure you could experiment with some different (lighter) springs on a corney keg pressure relief valve. they come apart and you can swap the springs out fairly easily. the stock ones release pressure somewhere above 100 psi. although the above is true; if the spring opens all the way at, say 20psi, its going to partially creep open when it nears that pressure. meaning a slow buildup of gas might be vented completely at only half that (meaning it would only hold maybe 10psi of a slow trickle of gas).

i would think that the cheapest thing for you to experiment with, would be to get a corney keg and cut a section off the bottom, and just weld/braze on a S.S. funnel. it will certainly take some skill (or atleast luck) to get it airtight, but a good braze should be able to hold 15psi like that.
 
I am fortunate enough to have a background in sanitary stainless tig welding, grinding, and polishing. So, my brew buddies and I put together a CORNY Keg CONICAL. It can ferment, secondary ferment, dump trub, harvest yeast, condition, carbonate, AND serve. We are testing it out with a batch of porter. She's a thing of beauty....

corny_keg_conical.jpg
 
I am fortunate enough to have a background in sanitary stainless tig welding, grinding, and polishing. So, my brew buddies and I put together a CORNY Keg CONICAL. It can ferment, secondary ferment, dump trub, harvest yeast, condition, carbonate, AND serve. We are testing it out with a batch of porter. She's a thing of beauty....

That is WAY COOL! I wish my welding skills were that good. What did you use for the cone and how do you stand it up?
 
I am fortunate enough to have a background in sanitary stainless tig welding, grinding, and polishing. So, my brew buddies and I put together a CORNY Keg CONICAL. It can ferment, secondary ferment, dump trub, harvest yeast, condition, carbonate, AND serve. We are testing it out with a batch of porter. She's a thing of beauty....

She is indeed a thing of beauty. Does she have any sisters, possibly for sale?
 
Its basic geometry at best. When you are ready, you will need a pair of aviation scissors( this is to cut along the curved lines), electric power shears(this is to cut straight lines) and some 20ga stainless sheet (this is the same thickness as that of your corny).

If you see my drawing below, a fermentation vessel is basically a cylindrical body with two cones(in industry the cones are domes instead). Making the cylindrical body is easy; its a square sheet. The tricky part is making the cone; its not a convential shape. However, it can be made from one correctly cut sheet.

The best way to learn this(i did it this way too) is to use a piece of paper and pretend that is your sheetmetal. Make plans to build a 6 inch tall fermentor. Choose the angles and radius of your tank body. Refer to the drawing. Build a mini-fermentor today!

CAM00752.jpg
 
If that is the diameter that you want, then yes, you could start with that.
You would have to trim off the flange, ( ideally), to facilitate butt welding it.
 
Stealthcruiser, the hopper you are refering to could potentially be used in liu of a fabricated cone. However, the price of the hopper is considerabely more than the cost of a home made cone assuming you have a tig welder and grinding equipment. The store-bought hopper still needs to be welded to the corny keg and a tri-clover ferrule.
 
Stealthcruiser, the hopper you are refering to could potentially be used in liu of a fabricated cone. However, the price of the hopper is considerabely more than the cost of a home made cone assuming you have a tig welder and grinding equipment. The store-bought hopper still needs to be welded to the corny keg and a tri-clover ferrule.


I concur..........I was responding to "onefeather" above my post.
 
onefeather,

I did one batch so far and had a contamination issue. I am planning to remove the quick disconnects and replace with 1/2 inch tig welded tri-clover ferrules. In addition, I am going to add a chugger pump and run sanitary lines from the fermentor to the boil kettle and back to the fetmentor to create a cip loop.
 
Thanks guys. I would be glad to make another one or walk you through the process if anyone is interested. We also made a tripod stand made of aluminum. The corny slides right in.

How much would you charge for one of these? I do 3 gallon batches, so this would be perfect
 
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