Making a unitank

[ethan44]

The spike stuff would be sweet for US prices - A couple of friends here who brew wanted their own unitanks, but if I was paying market value for time, it would work out cheaper just to buy a brewtech unitank. I'm only getting it for free because my BIL wanted to make one for fun and he tried my blackrock draught I made (he only drinks waikato #Hamilton) and liked it so wants me to make him some more.

Yeah I've been researching it a little bit and can see that the cost of a quality stainless steel welder's time is quite high. My workmate and I are (teachers in Christchurch) are always thinking about different career paths and that would be an awesome one for NZ. Considering that SS Brewtech 26L unitank is $1545, I don't think I'll be getting one (let alone 2) any time soon.

 

[Nommag]

Yeah I've been researching it a little bit and can see that the cost of a quality stainless steel welder's time is quite high. My workmate and I are (teachers in Christchurch) are always thinking about different career paths and that would be an awesome one for NZ. Considering that SS Brewtech 26L unitank is $1545, I don't think I'll be getting one (let alone 2) any time soon.

I mean the $1550 isn't even that bad when you consider time to make, materials, shipping to nz, all the accessories (which as I've found out are hugely expensive) and then on top of that pressure certification. You literally can't make them cheaper if you have to pay for time (it's taken 20 hours to get this far) and even just being able to weld isn't enough. My BIL is trained specifically to weld these sorts of things. I've really hit the jackpot, he is even considering building a copy of one of those like 30k brewtech minibreweries because he can. Sky's the limit.

 

[Nommag]

Just an update, the unitank has been sitting around in my brewing room for a few weeks now since my BIL lost interest in it. I was advised that it still needs an acid wash and he can build a blow off cane. The interest in it is gone for him though and he didn't want it at his house anymore but will finish it when I get the parts to start using it. It fits perfectly into my fermentation fridge which is great. But I'm very confused still at what parts I need to buy and if it will even work. I have ordered a bunch of cheap stuff off Ali like gaskets, tri clamp covers and a couple of tri clover barbed 10mm hose tails. But who really knows if they will fit probably since I only just measured it up today. I thought before I payed around $100nzd to buy the PRV and Pressure gauge i'd check what I have in front of me is practical and functional. The whole setup was free so its hard to be fussy at what I have, but i'd like to get some use out of it if I can.

The below image is the top, there are 2 small tri clover openings that are 50mm OD and 35mm ID. The middle opening is 167mm OD and 146 ID


The midrift has three tri clover openings that are 50mm OD and 35mm ID and the upper ball lock valve is also 50mm OD and 35mm ID. The large ball lock valve opening at the very bottom is 64mm OD and 48mm ID.



The bottom has a weird shape because my BIL wanted it to meet the fridge measurements, who knows how the shape will affect the draining of yeast and trub out of the bottom.

 

[SanPancho]

top needs a blow off port which can be a hose barb You’ll want co2 port which can either be the second small tc port or you can buy a cap for the big port that also includes a small tc port in it. The PRV is usually better off at highest point to prevent fouling but as long as you don’t fill tank too full it can go on smaller side tc port. You got options. You’ll want to be able to blow in co2 while adding dry hops so maybe side small port for co2 and prv in the cap of the big port. Shouldn’t be hard to find a cap with a port in it. Pretty common.

at the bottom of the cylinder you’ll want One port for your thermometer / thermowell, one for carb stone and then the third can be for racking arm. They look kinda close together so don’t get a big old racking arm as it will hit the temp probe or carb stone and won’t rotate. They’re too close together but that’s too late to change. Just make sure you buy parts that work together, or lose te stone and naturally carb.

no idea what to do with the port way down towards bottom of cone. Maybe a 3/4” tc ball valve to collect yeast? Never seen one there before so just spitballing ideas here.

 

[Qhrumphf]

Ideally that lower port would be your racking arm but it seems like it's a little low for that unless you could find a suitable arm that both gets high enough and rotates enough.

In lieu if that, i would out a second temp probe there.

 

[Nommag]

Thanks for the responses. That is a pain in regards to the lower arm being too low. I was hoping to rack from that. Its also a bit annoying that the ball valves are welded on, not attached with tri clamps. Is it possible to get a raking arm for an existing ball valve?

The tank size I believe is around 71-76 litres and the bottom cone is about 30 litres so the bottom cone is deceptively big.

The top port I believe is 6 inches so I'd need to find a 6inch to 1.5inch lid to put the prv on it

 

[Nommag]

It may pay to add my bil doesn't homebrew, he just welds. He has welded together milk tanks and beer tanks in the past but to spec. I was able to offer no real specs because I've never used a unitank. I just sent him some pictures I found on Google and the information I gathered here and that is what he dropped off. So if there is anything unusual it's not some kind of secret, just something we got wrong

 

[Qhrumphf]

Those are butterfly valves, not ball valves. You won't be able to put anything through them without disabling the valve. If that butterfly is welded on then it's basically useless.

 

[Nommag]

Those are butterfly valves, not ball valves. You won't be able to put anything through them without disabling the valve. If that butterfly is welded on then it's basically useless.

Damn! I'll have to have a yarn with my Bil maybe he can replace it with a tri clover port.

 

[Qhrumphf]

Remove the valve, weld on a TC ferrule. TC racking arm goes through it. Butterfly then connects to racking arm.

If you religiously and repeatedly dump your cone you *may* be able to rack from that port, but that's a long steep cone and you're right at the bottom. Your upper ports would do for a racking arm but you'd need one long enough. If he's gonna custom fab for you you'll want a pretty steep one and may have just accept you can't get full rotation and have the arm be long enough (from either port, really)

Think if your average losses. If you never dumped you might have 10% of your volume be yeast/trub (more if you dry hop heavily). If you dump it properly twice, might knock that down to 3-5%. I'd fill it with those volumes of water and see where it sits in relation to that valve (ie if your normal batch size is 60L put in 3L, have a look, then another 3L. Might be able to sight out a racking arm length that way.

 

[Gruel]

Why would he need a racking arm if he has a dump valve at the very bottom?