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SS Brewtech Unitank

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Shaunus_Maximus

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Hey everyone,

Newbie to the forum here,.. and mildly new at brewing. I probably done around 20 batches since starting, and the first 15 in your basic fermenter. The last 5 have been in the 56ltr SS Brewtech Unitank.

The beer itself is fine, but I have to say I'm having quite a few issues with this thing and I'm a bit lost as to why:

1. When under pressure the blowoff valve (set to 10psi) always overflows and I end up with a fair mess on the top of the tank,.. mostly cosmetic I think but no one else seems to have this problem?

2. When kegging, I cannot tell you just how much trub ends up in the final product. I don't often dump this off, as I assumed that it all sits at the bottom of the conical? Maybe its all picked up because its carbonated when I keg? Its got to the point where I loose at least a few pints from every keg whilst I muck about trying to get the taps to pour as it keeps clogging up the posts :( Last time, I tried to keg off through a filter and all it did was make a massive mess and still ended up with, what looks like even more trub. I'm at a bit of a loss :( any tips? Am I supposed to be dumping the trub? should i release the pressure before doing so?

Thanks in advance
Shaun
 

duncan.brown

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When are you closing the tank? Typically, you want the blowoff valve open and have a hose going from the valve into a growler of starsan until you’re only a few gravity points away from FG (the exact amount depends on the level of carbonation that you want in the finished beer). Even then, you should really have a spunding valve to check the pressure to the right level, rather than relying on the pressure-relief valve. The unitank doesn’t come with a spunding valve, so you’ll need to pick one up.

Note: when I say blowoff valve, I mean the valve at the bottom of the blowoff arm with the blue handle, not the valve on the top of the tank (which is the pressure relief valve and should never open under normal operation). It shounds like you’re leaking out of the PRV?

As for dumping trub, yes, you should use the bottom dump valve to dump trub and yeast before kegging (and sometimes during fermentation, depending on the beer). I normally dump yeast before pressuring, as if you dump under pressure, the beer can punch a hole in the yeast and it just squirts out beer. Hop matter can be dumped later.

You might also want to check the position of the racking arm when you’re kegging. When you assemble the racking valve, make a pencil mark on the outside of the butterfly valve to show the level of the arm. Then when you come back a week later and forget where you positioned it, you can use the pencil mark to adjust it.
 
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Advance

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To answer your first question you should do what duncan.brown advised above about using the ball lock blowoff valve to allow any blow off to be collected into a container during high krausen. You might need to purchase a barbed fitting and some tubing to make this connection. While I do not know the specifics of your process upstream of kegging, your problem with transfering large amounts of trub is more than likely a result of allowing the pressure in the unitank to drop as you are transferring to the keg(s). The unitank must be kept under pressure greater than or equal to the head pressure reading you carbonated too. If the pressure is allowed to drop, the beer will begin to off gas. This will cause CO2 bubbles to form on the trub and lift it into your bright beer, which will then be transferred into your kegs. This thread should help you address this problem:

 

duncan.brown

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The unitank must be kept under pressure greater than or equal to the head pressure reading you carbonated too. If the pressure is allowed to drop, the beer will begin to off gas. This will cause CO2 bubbles to form on the trub and lift it into your bright beer, which will then be transferred into your kegs.
Yep, forgot to mention this. Another good reason to get a spunding valve. When I keg, I put my spending valve on the gas out of the keg and use my carbon dioxide regulator to maintain the pressure in the Unitank when transferring. If you're just releasing pressure when you keg, the carbon dioxide is going to come out of solution and stir everything up, as @Advance says.
 
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Shaunus_Maximus

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This answers both my questions, thanks so much guys. I had a feeling that was what was happening but wasnt sure how to resolve. I'm a bit unsure how to use this spunding valve, I'll just have to buy it and give it a go. Can you not just set the regulator on the Co2 to the same pressure shown on the unitank?

I definitely think not pressuring until the final days of fermentation and dumping the trub before pressuring is going to solve an awful lot of problems! Thanks so much
 

duncan.brown

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I'm a bit unsure how to use this spunding valve, I'll just have to buy it and give it a go. Can you not just set the regulator on the Co2 to the same pressure shown on the unitank?
The regulator lets gas in, the spunding valve lets gas out. Here's what a complete brew looks like for me:
  1. From the start of fermentation to desired carbonation gravity, the ball lock blowoff valve is connected to a hose that goes to a bucket of Star San. For example, the last lager I did had an SG of 1.040, starting at 48F. I ramp the temp over 100 hours to 58F. Fermentation is not pressurized during this time.
  2. I dump the years (34/70) fairly often. No dry hopping in this beer, so no hop trub, though.
  3. When I hit my desired carbonation gravity, I close the blow-off valve, replace the hose with a spunding valve set to the right pressure, and open the valve.
  4. At 1.013, I started spunding at 58F and 13 PSI. When it hit 1.010, I closed the blow off valve and lowered the temp to 41 F. The FG was 1.008 and the carbonation was about 2.6 volumes.
  5. I crash cool to 32 F.
  6. When I transfer, I hook up my regulator to the Unitank set to 20 psi. I move the spunding valve to my keg and set it at 11 psi (higher than the pressure required to main carbonation, but lower than the pressure in the tank that is pushing the beer.
  7. Then I get carbonated beer in the keg.
You need more parts than you get with the Unitank to do this. I replaced the blue ball valve with a butterfly valve that has 1.5" triclamp fittings on both sides (just a cheap one from Amazon, not the SS Brewtech ones). I then have a variety of fittings (TC to barb, TC to 1/2" NPT to spunding valve, TC to gas connect) that do the trick.
 

slidingmike

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Is there a good formula I could use to calculate the correct gravity to start spunding, given the variance of headspace vs beer volume (and of course target volumes)? I've been mostly guessing, and have both pulled the trigger a bit early and stunted my fermentation, or waited to late and then had to supplement with CO2 head pressure.

Thanks, any pointers would be great!
 
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