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DavidLenzini

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Hi all. New member, but quite a long time home brewer.

I have just upgraded to a SS Brewtech 14 gallon Unitank and am generally really happy with the flexibility this offers. However I’m quite confused with the whole CO2 set up and how to best package oxygen free (I’ve always bottle conditioned in the past).

Can anyone point me to a 101 guide for using CO2.

Better still, If anyone can help me out with something that is puzzling me? The pressure gauge on the unitank has been stuck on zero from day one. I’ve popped the cap to equalise the pressure, but it just hasn’t moved. It’s installed at the top where all instructional videos and guides suggest it should be and is securely fastened with a TC clamp and gasket (as are all other connections). No other valve has been left open including the blow off cane.

Fermentation has finished (I left the spunding valve open initially - but saw no bubbling at all so closed a few points before terminal gravity). Today I’ve connected gas up and left it pushing CO2 through the carb stone at 10psi for 5 mins or so (and could hear the beer bubbling away). However the pressure gauge never once moved.

Am I wrong to think the pressure gauge should start to move straight away, or is there just not enough pressure in the tank to affect the gauge? Surely there would have been during fermentation?

I guess it’s possible there’s a leak, but surely I’d be able to hear the gas leaking or see the beer leaking from somewhere? And wouldn’t the tank still pressurise but slowly lose pressure?

Just trying to understand if I have a faulty pressure gauge or am I just getting this all completely wrong?
 

Jtvann

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Hey there. Only a few possibilities here. Start this on your next brew session.

Take everything apart. All the parts and pieces. Take your pressure gauge and push up on it with your finger into the round metal bottom. When you do this, the needle should move. Don’t do it hard or with any sharp objects, just your finger. It’s possible your gauge is broke, but I doubt it. If the needle moves when you push on it, doesn’t mean it’s accurate, it shows it will react to pressure off zero.

Next, install all parts with gaskets etc. tighten then down good. Hand tight is enough, but good and tight. Close off all valves. Hook your CO2 into the blow off arm. Set psi to about 15. That’s about as normal high as you’re going to operate. Make sure the tank is empty. You’ll use a good amount of CO2, but it’s worth doing once. Fill to 15 psi by your regulator gauge. Confirm the pressure with your unitank pressure gauge. Note any differences and then flip a coin as to which to trust. Make sure though to give it enough time to fully get to equilibrium. I hook everything and leave the pressure there and let it sit for a while. A few hours or over night. Confirm the pressure didn’t drop any. It shouldn’t.

Release pressure by the blow off completely. Take off your carbonation stone and hook it up to a CO2 line. Only the stone separate from the tank. Put the stone submerged in water and slowly turn up pressure. Very slowly. Note when bubbles start to come out. I’m bettering it will be between 3-5 psi. This is your wetting pressure. When carbonating you’re a certain psi, say 10 at 37 degrees, add your wetting pressure to your regulator. If wetting pressure is 4, you’d set your regulator to 14.

More to come later
 
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DavidLenzini

DavidLenzini

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Great, thanks for these first steps. I have taken the pressure gauge off to inspect but didn’t think to push lightly on the bottom so will give that a try. My pressure gauge is screwed into a 1.5” TC with ridges at the bottom, but no hole (which surprised me). Am I pressing on this or unscrewing the pressure gauge from its TC fitting first?

Also, just to be clear about blowing CO2 up the blow off cane - do I remove the ball lock valve and replace with a TC-gas ferrule or is there some other way to get a good seal using the ball lock connector and gas line?
 

Jtvann

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Don’t unscrew it. Press from the round ridged part.

Up to you on the seal. You can leave the TC ball valve there and put in a barbed connection.
 
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DavidLenzini

DavidLenzini

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How long should I blow CO2 into the vessel before expecting to see any movement on the pressure gauge?
 
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DavidLenzini

DavidLenzini

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I went into my brew area this morning to find the pressure gauge just slightly off the needle, finally! I'm guessing the disconnecting and reseating the gauge last night and checking the other top tc fittings must have sealed a very slight leak. I've now pressurised at 10psi via the carb stone, which took about 15 mins - but it's still at ambient temperature (16c / 62f).

I guess I probably need to release the pressure again to allow any oxygen out that got trapped in when disconnecting the top connectors yesterday - but at least I'm pleased to say the gauge is working - and the tank has held the 10psi pressure for the last hour, so all good.

I'm still, admittedly, not very savvy about the whole CO2 process, I do have the carbonation chart and will use this when transferring under pressure into my keg - but I'm just worried this tiny soda stream bottle will run out before the process is finished. It's only a 30 litre batch and it was a brand new gas bottle, but I just can't get my head around this tiny gas bottle (465g) pressurising the 14 gallon unitank, purging a keg, transferring the beer and purging the headspace after. Though I'm sure I'll get used to it after a while.

Thanks again Jtvann.
 

VikeMan

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I'm still, admittedly, not very savvy about the whole CO2 process, I do have the carbonation chart and will use this when transferring under pressure into my keg
Carbonation charts tell you how much pressure you need over a long time to reach your desired CO2 volumes (carbonation level) at a given temperature. They don't say anything about the pressure needed for transfer (which is usually less).
 
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DavidLenzini

DavidLenzini

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Thanks @VikeMan. I understand that transfer needs much less pressure to push through, but beyond that is where I start confusing myself.

I had 10psi added into the tank, which took around 15 minutes, I pushed this in through the carb stone and the beer therefore became carbonated (evident when pouring a sample from the sample tap). However different information I read suggest you need to carbonate over a much longer period of time and I don't really understand why. I also don't understand the difference between the volumes of CO2 in the beer and the pressure in the headspace.

Can anyone point me to a starter's guide for using/understanding CO2?
 

VikeMan

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I had 10psi added into the tank, which took around 15 minutes, I pushed this in through the carb stone and the beer therefore became carbonated (evident when pouring a sample from the sample tap). However different information I read suggest you need to carbonate over a much longer period of time and I don't really understand why.
10 PSI for 15 minutes didn't carbonate your beer appreciably. If you're seeing foam on your samples, it's mostly from residual dissolved CO2 from fermentation.

I also don't understand the difference between the volumes of CO2 in the beer and the pressure in the headspace.
Volumes of CO2 measures the actual amount of CO2 dissolved in the beer. Headspace pressure is what you need in order to force the CO2 into the beer when force carbonating. For any given temperature and CO2 volumes, there is a specific pressure (on the chart) needed, for a long time, to get those volumes into the beer. Once those volumes are finally reached, no more (net) CO2 will dissolve, i.e. you'll be at equilibrium, where the tiny amount of CO2 entering the beer will be exactly offset by CO2 leaving the beer.

This might help:
 

Jtvann

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If you need any more help, feel free to PM me.

When you go to keg or bottle, you’re going to want to figure out a way to hook your CO2 into the blow off arm and not the carb stone.

The carb stone has to bubble CO2 in which can stir up your beer. It’s also very slow compared to the blow off. I’m not sure what CO2 cylinder your using ... a soda stream?

I’ll take a picture of mine when I go outside. I like duotight connections. I’ve got mine setup so that I can run eva barrier tubing direct from my CO2 tank regulator into the unitank. You’d need something like this to go into your ball valve.
 

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DavidLenzini

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Thanks @VikeMan that definitely helps explain things a bit for me. Though I'm not sure the foam had much to do with fermentation as it's been totally flat until I injected the CO2 earlier today.

Thanks also @Jtvann - I did wonder about pushing CO2 through the carbstone as the sample was obviously full of hop matter (not due to dump hops until Friday). I do have a TC to barb ferrule, so can switch the ball lock for that and carbonate through the blow off cane, that's just for the transfer through, correct? If I wanted to cold crash in the unitank after dumping the hops - I should still carbonate the beer through the carb stone, right? Also for how long - I've read the unitank can be pressure carbonated in 24 hours (though other places say a week).

The soda stream is just a tiny 425g cylinder used in a popular drinks machine to carbonate drinks (see below) - I have a regulator on this which I can set to match the required psi of the tank.
 

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Jtvann

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Think of it this way. You ferment beer, and it’s mostly uncarbonated. There’s some CO2 in there but not much. So you need to add some to get it to the level you want.

The unitank give you 2 ways to do that, and both work fine.

To carbonate, you need to make CO2 come into contact with your beer under pressure. Different liquids will absorb different gasses at different temperatures. The colder they are the more gas they’ll absorb. What you want to do is figure out how much you want. Say 2.5 volumes. That’s on carbonation chart scale for many ales. It’s fine to pick 2.2 or 2.7. It’s your choice for your beer. You’re making it for yourself, so you get to decide what you want. I’d suggest to stick to the recommended range.

Next, decide what temp you want to drink your beer at. Do you want it cold as the rockys ... aka coors light? That’s as cold as your fridge will get it. Probably in the 33-34 temp range. Many people won’t tell you to go that low, as cold temps can mute flavors in a lot of good beers. I personally set my kegerator to 38 degrees with a 1 degree variance. So my beer is served at 37-39 degrees.

Ok, so using my example of 38 degrees and wanting near 2.5 volumes of CO2. I’d need to set my regulator pressure to 11 psi. It gets me very close.

So the 2 ways the unitank can carbonate. If you put your CO2 into the blow off arm, all the gas will go into the head space. It should show as 11 psi on your unitank pressure gauge as well. That CO2 being at pressure will force its way into your beer slowly. Maybe take it a week or more. 2 weeks for sure and it’s good.

The other, much faster way is to use the carbonation stone. Starting from the beginning, Hook your CO2 line into the carb stone. Remember that first post I wrote about wetting pressure? You need that number in the long run, but you can skip it for now. Set your regulator to about 6 psi. You’ll hear bubbling. Leave it there for about 2 hours, then come back and ever so slightly give it more pressure. Let it sit 2 hours. Then give it slightly more. Keep doing that over and over until after a while your going to see your unitank pressure gauge reading 11 psi. At that point let it sit and don’t add anymore.

The advantage of the carb stone is that it puts tiny bubbles into your beer. If they’re super tiny they float up nice and slow. So slow that they never make it to the top of your beer. They’re absorbed into solution. That’s why I say increase pressure ever so slightly. If you just jam it up too high too fast you create big bubbles. Big bubbles rise very fast and can’t get absorbed before they just blow into the head space just the same as if you did your blow off arm.

You still need to let it sit and wait a while. At first, using the carb stone, I’d give it a week at pressure. When you fine tune your process and get good at it, if you want to rush, you can carb beer in about 24-48 hours pretty easy.
 
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DavidLenzini

DavidLenzini

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That’s absolutely the response I was looking for and so clearly explained too. Thanks so much.

I’m guessing if I leave the gas hooked up, the regulator means it only adds pressure when it drops below the set psi so the gas isn’t just going to run out from leaving it on.

sorry, I really meant it when I said I know nothing about CO2 🤣
 

Jtvann

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No worries. You’ll figure it out. Again though when bottling or kegging, use the blow off arm and not the carb stone. Carb stone will kick up bubbles and stir your beer possibly making it cloudy. The blow off arm will push the beer from the top without bubbles. It’ll also do it much faster.
 
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DavidLenzini

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Hopefully the last question for now. Once the beer is carbed. Do I need to vent the tank so the gauge shows it’s on 1-2psi for the transfer and set regulator to match so the beer flows?

I assume by releasing the pressure this actually only removes the gas in the headspace and doesn’t mean the beer loses carbonation?
 

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Hopefully the last question for now. Once the beer is carbed. Do I need to vent the tank so the gauge shows it’s on 1-2psi for the transfer and set regulator to match so the beer flows?

I assume by releasing the pressure this actually only removes the gas in the headspace and doesn’t mean the beer loses carbonation?
The beer will start losing carbonation, but it is a long process (just like carbonating) so as long as you are done transferring within the next hour it won't lose much.
 

Jtvann

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I would not vent any pressure. It all depends on how you’re kegging or bottling. I always do it under pressure.

Which are you planning to do, keg or bottle?
 

bleme

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I would not vent any pressure. It all depends on how you’re kegging or bottling. I always do it under pressure.

Which are you planning to do, keg or bottle?
If the vessel he is moving it to has been properly liquid purged, then I agree - no point not moving it as fast as possible. But if there is any oxygen at all in there, then lower pressure will limit splashing and O2 exposure.
 
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DavidLenzini

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Cool, good to know thanks. Will be kegging this time, will purge first for sure.

I do have a new counter pressure bottle filling rig I need to get acquainted with too, guessing I should reduce the pressure if using that?
 

Jtvann

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No. If you’re counter pressure bottle filling, or keg filling, the neat way to fill is keeping pressure at carbonation pressure. When I get more time, I’ll reply with a detailed process. You should be able to search the forums and find it though.
 

Jtvann

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If kegging you need what’s called a spunding valve. This is one from morebeer, but you can find one in many places.


First thing you’ll do when ready to keg is to completely clean your keg. Then fill the keg to the top completely with sanitizer. Meaning 5 gallons of water and 1oz of starsan. Fill it to where it’s over flowing almost. Just take the keg lid off and pour in water and then pour in starsan. This will be the last time you take the keg lid off before cleaning and filling with a new beer.

Let the sanitizer solution sit for a while. The bottle will tell you contact time. I typically let it sit 30 minutes or so, shaking it every once in a while.

Hook your CO2 tank up on the gas in side and set the regulator to a littler higher than your carbonating pressure. Around 15 psi or so. I waste some CO2 in my process, but it’s minimal and I feel worth it. Attach a liquid out line and drain the starsan. You can save it for use later. You’re basically running all the sanitizer out and replacing it with near 100% CO2. Do not open the lid for anything or you’re wasting all your work. At the end your keg should be full of nothing but CO2 at about 15 psi.

Attach your spunding valve set to maximum high pressure. Slowly dial it back looking at the pressure gauge. Eventually the spring will give and CO2 will start to come out. Continue to dial it back until you have just BELOW the pressure in your unitank. No equal to. Definitely not above. Just below. If unitank is at 11, spunding is set to 10.

Once gas stops hissing, you have a correctly pressurized keg ready to fill.

I love eva barrier tubing and duotight fittings. Here’s a link to parts you’ll need.





Attach the 1.5 TC to 1/4 mfl flare to the racking port on the unitank. Not the bottom dump but the one above it. Attach a duotight fitting to the flare. Attach another duotight fitting to the black ball lock connector. Push in line to connect the two. A few feet is enough, probably 3-4 feet. Connect the black ball lock to keg. The spunding valve should still be connected to your gas side.

Connect your CO2 cylinder to your blow off valve and set regulator pressure equal to or higher by a bit than your current carbonation pressure. Maybe somewhere from 12-15. Make sure the blow off valve is open so that CO2 will push beer when you open the valve.

SLOWLY open the TC valve to your racking port. Since pressure is slightly lower in your keg from your unitank, beer will flow. The spunding valve will keep the correct pressure inside the keg, and as beer flows in, gas will flow out. When beer come squirting out of the spunding valve, your keg is full.

Assuming you gave your beer plenty of time to settle, cold crashed etc, you shouldn’t have clogs. Highly dry hopped beer may require extra filtration and Incan explain that later.

The above steps are the best and safest way to do everything right in my opinion. Everyone has a different opinion and process, but this is mine and it works. There are easier ways to do it and plenty of steps you can skip or do different. I have beers near a year old in some kegs that have been stored warm and they still taste good.
 

Jtvann

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To explain the easy way just in case you’re wondering ... not sure why anybody would choose this method after spending the money a unitank costs ...

1-Open the keg lid
2- Attach a line to the racking port on unitank
3- Put line in keg.
4- Open valve and fill.
5- Lid on keg and purge headspace.


You can make it as complicated or as simple as you like.
 
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