[mbalon]

Hey all,

I’m looking at getting a half barrel unitank a couple of months from now. The plan is to get a 20lb CO2 tank to carb it, and counter pressure fill bottles from the tank itself. Now, my question is...

Should I have any worries using a 20lb tank and carbonating a half barrel of beer (along with bottling it) in a small 10x10 or 12x12 room? What if there’s a slow or small leak or if a hose somehow slips off of a barb?

[a10t2]

Yes, CO2 in a confined space can be potentially dangerous. Take the usual precautions (use hose clamps, check for leaks, etc.) and you'll be fine; people work safely with CO2 all the time and a small leak won't harm anything other than your wallet.

[macbrews]

One of the nice features of a unitank (assuming it is by SSBrewtech) is that you can condition it in the tank and not have to force carb it. All you have to do is turn the valve on the blow off tube and it will carbonate itself. The 15 lb prv will allow you to spund and carbonate it to that level.


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[a10t2]

The 15 lb prv will allow you to spund and carbonate it to that level.

Spunding rocks. Some additional safety notes there though:

Make sure your conical is rated AND TESTED to 30+ psi. It's pretty common for cheap tanks to be rated for 15 psi.

PRVs are not spunding valves: they aren't designed with that level of precision in mind, and more importantly by using them as such you no longer have a safety valve in the system. Safe spunding requires both.

[mbalon]

Yes, CO2 in a confined space can be potentially dangerous. Take the usual precautions (use hose clamps, check for leaks, etc.) and you'll be fine; people work safely with CO2 all the time and a small leak won't harm anything other than your wallet.

Hose clamps and leak checks are a definite from me. I hose clamp everything now anyway.

One of the nice features of a unitank (assuming it is by SSBrewtech) is that you can condition it in the tank and not have to force carb it. All you have to do is turn the valve on the blow off tube and it will carbonate itself. The 15 lb prv will allow you to spund and carbonate it to that level.


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You’d be correct that it’s from SS Brewtech. So basically I could just hook the CO2 up to the stone, set the spunding valve for the PSI I want, and it’ll carbonate over time at 40 degrees while cold crashing? Or do I not even need a CO2 source at that point? Just a spunding valve and it’ll carbonate itself during fermentation?

The 15 lb prv will allow you to spund and carbonate it to that level.

Spunding rocks. Some additional safety notes there though:

Make sure your conical is rated AND TESTED to 30+ psi. It's pretty common for cheap tanks to be rated for 15 psi.

PRVs are not spunding valves: they aren't designed with that level of precision in mind, and more importantly by using them as such you no longer have a safety valve in the system. Safe spunding requires both.

It’s an SS Brewtech and I know it’s rated up to 30 PSI (might even be more, but I know it’s at least 30) and I also plan on using a spunding valve with it also, so no worries there.

[a10t2]

You’d be correct that it’s from SS Brewtech. So basically I could just hook the CO2 up to the stone, set the spunding valve for the PSI I want, and it’ll carbonate over time at 40 degrees while cold crashing?

Most likely even a lager strain won't want to stay active at 40°F. Hence the high pressure requirements for carbonation in a unitank: at 20°C/68°F it takes 28 psi to carbonate to 2.5 vol and since you're at the very end of fermentation (diacetyl rest or whatever you want to call it) temperatures for ales would typically be a little higher.

It’s an SS Brewtech and I know it’s rated up to 30 PSI (might even be more, but I know it’s at least 30) and I also plan on using a spunding valve with it also, so no worries there.

Their site says 15: https://www.ssbrewtech.com/collections/all-unitanks/products/half-bbl-unitank so it might be worth clarifying before you buy.

[mbalon]

You’d be correct that it’s from SS Brewtech. So basically I could just hook the CO2 up to the stone, set the spunding valve for the PSI I want, and it’ll carbonate over time at 40 degrees while cold crashing?

Most likely even a lager strain won't want to stay active at 40°F. Hence the high pressure requirements for carbonation in a unitank: at 20°C/68°F it takes 28 psi to carbonate to 2.5 vol and since you're at the very end of fermentation (diacetyl rest or whatever you want to call it) temperatures for ales would typically be a little higher.

It’s an SS Brewtech and I know it’s rated up to 30 PSI (might even be more, but I know it’s at least 30) and I also plan on using a spunding valve with it also, so no worries there.

Their site says 15: https://www.ssbrewtech.com/collections/all-unitanks/products/half-bbl-unitank so it might be worth clarifying before you buy.

I understand what you’re saying about the strains, I thought you were referring to carbonating it while it’s cold crashing at the end of secondary. As for the PSI ratings I just found all of the specs, recommended is 15, max operating is 30, and tested was 60. But if I plan to carbonate the half barrel in the fermenter while it’s cold crashing at 38 or 40 degrees, it should be about 12 or 13 PSI to carbonate it to 2.5 volumes, correct? And then when I plan to transfer it to a keg or bottle it from the tank I’d probably be bumping it up to 15 PSI.