Cold crash w pressure question?

[USMChueston0311]

i applied 5 lbs of co2 to my spike CF15 conical, cold crashed down to 37, and its holding there. Being the first batch in new system, and conical, I removed the pressure and put the blow off tube back, did I screw myself?

Or do you only need that co2 pressure when your actually dropping from fern temp down to cc temp?

 

[Mer-man]

Well, you probably lost some CO2 as it equilibrated to atmospheric, and you are going to experience gradual oxidation as atmospheric O2 saunters (technical term) in.

You didn't help yourself, that's for sure.

Positive CO2 pressure when reducing temp prevents a vacuum situation that many vessels have trouble with. So you started with a good idea. You could have just set your CO2 to carbonate to the appropriate volumes at 37F, and left it there for a week or so as it, and after it, crashed.

If your conical is pressure-capable, you could try spunding next time: based on a FFT (countertop, not stirplate), cap your fermentor at 4-6 points above FG and let it go for 3-4 days. Then cold crash it and a) it will be carbonated nicely, and b) it won't have a problem with cold crashing.

Ta daa.

 

[USMChueston0311]

So I figured it all out. I needed 5 psi at start of cold crash, and keep it in place until done. It only took 12 hours as 11 psi to carbonate to 2.4 of carbonation. Removing the pressure and reinserting blow off tube caused me to suck back 2-3 cups of starsan into my 10 gallon batch. Will do it better next time ;(

 

[auburntsts]

Another option is to buy Spike's long blowoff tube with 1.5" TC fittings on both ends. That way you can attach their gas manifold right to the end of the blowoff tube when you're ready to cold crash and never have to take the blowoff tube off at any point. At the end of the crash you can then do a closed loop pressure transfer to a keg by reducing the CO2 pressure to like 2 lbs, or increase the pressure to carb in the conical like you attempted to do this time.

 

[mongoose33]

So I figured it all out. I needed 5 psi at start of cold crash, and keep it in place until done. It only took 12 hours as 11 psi to carbonate to 2.4 of carbonation. Removing the pressure and reinserting blow off tube caused me to suck back 2-3 cups of starsan into my 10 gallon batch. Will do it better next time ;(

I have the Spike CF10. I have the pressure manifold on mine, and I attach a QD to the manifold and terminate the tubing in an airlock jar.

When I want to finish by carbing naturally, I'll simply pull off that QD which seals the fermenter and now any CO2 will carbonate the beer.

I do question how you got what I presume is 2.4 volumes of CO2 in your beer. Mine tops out at 13 psi before the PRV releases pressure. Since I'm finishing fermentation at, typically, about 65 degrees, the amount of CO2 the beer can absorb is shown by this chart:

At 13psi and 65 degrees, I'm only going to be able to produce 1.58 volumes. When I crash the fermenter down to, say, 40 degrees, I won't have 13psi any longer--it'll be less.

Are you continuing to pressurize the fermenter at 12psi as it chills down? That's the only way i can see you getting 2.4 volumes, and I would question whether that's possible in 12 hours--unless you're using the carb stone. Is that how you're doing it?

 

[USMChueston0311]

I have the Spike CF10. I have the pressure manifold on mine, and I attach a QD to the manifold and terminate the tubing in an airlock jar.

When I want to finish by carbing naturally, I'll simply pull off that QD which seals the fermenter and now any CO2 will carbonate the beer.

I do question how you got what I presume is 2.4 volumes of CO2 in your beer. Mine tops out at 13 psi before the PRV releases pressure. Since I'm finishing fermentation at, typically, about 65 degrees, the amount of CO2 the beer can absorb is shown by this chart:

View attachment 594072

At 13psi and 65 degrees, I'm only going to be able to produce 1.58 volumes. When I crash the fermenter down to, say, 40 degrees, I won't have 13psi any longer--it'll be less.

Are you continuing to pressurize the fermenter at 12psi as it chills down? That's the only way i can see you getting 2.4 volumes, and I would question whether that's possible in 12 hours--unless you're using the carb stone. Is that how you're doing it?

I carbed at 37 degrees, and 11 psi is 2.48.

I cold crashed down to that with my glycol chiller. And then set 11psi at reg in fermenter to achieve 2.48 of co2.

Did you read the above posts? If so you would see that I cold crashed and then carbed. I would NEVER carb at 65 degrees.

 

[USMChueston0311]

And yes I’m using the carb stone. And that same exact chart which is hanging on my wall.

 

[USMChueston0311]

Another option is to buy Spike's long blowoff tube with 1.5" TC fittings on both ends. That way you can attach their gas manifold right to the end of the blowoff tube when you're ready to cold crash and never have to take the blowoff tube off at any point. At the end of the crash you can then do a closed loop pressure transfer to a keg by reducing the CO2 pressure to like 2 lbs, or increase the pressure to carb in the conical like you attempted to do this time.

The solution is to just leave the gas manifold on with 2-5 PSI, for the duration of cold crash, then simple install carb stone, and gas up to correct pressure.

 

[mongoose33]

I carbed at 37 degrees, and 11 psi is 2.48.

I cold crashed down to that with my glycol chiller. And then set 11psi at reg in fermenter to achieve 2.48 of co2.

Did you read the above posts? If so you would see that I cold crashed and then carbed. I would NEVER carb at 65 degrees.

And yes I’m using the carb stone. And that same exact chart which is hanging on my wall.

OK, but you didn't say the carb stone. A "set and forget" method typically takes 10 days to 2 weeks to fully carb, and you did it in a day. That's what I was asking about, as it was too fast...unless you used a carb stone.

And why would you never carb at 65? I'm allowing as much self-carbonation as possible, so as to limit the amount of CO2 I need to provide from a tank. Such CO2 isn't pure CO2, contains some oxygen, and the less of that I need to provide, the better.

 

[day_trippr]

fwiw, I cold-crash under .4 psi. Unless one is trying to get a head start on carbonation I don't see the need to go any higher...

Cheers!

 

[USMChueston0311]

I don’t do it that way anymore. I like the results with cold temps and co2, with a keg. Done it both ways. I prefer the new way with my setup. Never had a problem with supposed oxygen with forces carbonation.

There is a lot I didn’t say.

 

[auburntsts]

So I figured it all out. I needed 5 psi at start of cold crash, and keep it in place until done. It only took 12 hours as 11 psi to carbonate to 2.4 of carbonation. Removing the pressure and reinserting blow off tube caused me to suck back 2-3 cups of starsan into my 10 gallon batch. Will do it better next time ;(

Can you elaborate on what your plan was after you cold crashed and then put the blowoff tube back on (ie regular gravity transfer to a keg vs closed pressure transfer (CPT), etc) since you both crashed under pressure and then carbed? Because I'm not following our process here. Kinda seems you figured out that if you are going to carb in the conical (either through spunding or via the carb stone) then the logical thing is to CPT, otherwise what's the point.

I also don't understand how relieving the pressure to an already cold crashed vessel caused suck back . There shouldn't have been any vacuum in what you described to cause it. So what created the suck back? Am I missing something from that post?

Just to understand your setup, do you have your carb stone on the racking port and manifold with the PRV on the lid?

 

[USMChueston0311]

I have a spike CF15, with gas manifold on top next toncooling coil. Before gas valve I use a blow off port and tubing into a sanny bucket. I got confused with the instructions, and thought I only needed the pressure and manifold while crashing down in temp, and thought once it reached crash temp you had to switch back blow off tube. That was just poorly written instructions and me being a noob with a conical.

I’m guessing at cold temps, with external temps being warm, and rising up, cooling back down with temp control etc, causes a vacuum still. Physics, above my head. But sure as ****, after I replaced the blow off tube, I saw starsan all the way up the tube, and my butter cup was half way lower w starsan. I also heard a gurgling sound when taking a sample which would indicate it was sucking oxygen in, or a vacuum depressurizing.

I talked with spike and they said you leave it on with pressure for the duration of crash and carb. It only makes sense as you then use the same manifold to match carb pressure.

And yes carb stone goes on racking valve and gas manifold on the lid.

It wasn’t relieving the pressure that instantly caused the vacuum, it was removing pressure and physics taking over a period of time sucking it all in. My beer is garbage. Complete waste. Totally oxidized, and disgusting. First bad batch in 12 years of brewing I’ve ever had.

 

[auburntsts]

Thanks for the info and sorry to hear about the batch. Maybe someone smarter than both of us will come along and explain as to what caused the suck back in your case. The good news is you've got the equipment and process sorted so next time the beer will be fine!

 

[USMChueston0311]

I’m Pretty sure it’s the cold temp in conical in a warm environment. That demo differences causes pressure changes in a negative way. Spike agrees.

 

[auburntsts]

Hmmm, that doesn't seem right since you cold crashed under pressure and then released the pressure back to atmospheric unless you continued to cool once you put the blowoff tube back on.

 

[USMChueston0311]

It does make sense. You’re keeping a vessel at 38 in an ambient of 68-72. Like a beer that sweats etc. there is pressure changes related to temp offsets like that.

And the conical rising temp then cooling, rising and cooling etc. it’s just what happens.