Can we talk pressure fermentation & related processes?

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Hwk-I-St8

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I just got a fermzilla all-rounder with the intention of fermenting under pressure. Poking around, I haven't really seen much about how people are doing this. Here are some questions I have:

  1. What pressure do you use? The Fermzilla can do up to 35 psi, but I'm guessing I don't want to go that high. What's your choice and why?
  2. Do you start out w/o pressure and then ramp up as fermentation progresses? The fermzilla comes with standard ball lock connectors, I could use my CO2 tank and generate some initial pressure. I'm guessing letting it happen naturally would make more sense, just thought about it as a way to adjust my spunding vavle.
  3. I would like to use the CO2 output from the ferm to push starsan out of my keg. Will the pressure eliminate the risk of krausen blowout or will I still need a blowoff tube? I'd like to run my usual duotight connectors and tubing...going from the vent ball lock on the ferm to the gas in on the keg 1. Then liquid out on keg 1 to liquid on keg 2 (to capture the starsan pushed out), with the spunding valve on the gas port of keg 2. Is this viable or will I risk hoses and connectors getting clogged with krausen?
  4. If I open it to add dry hops, should I re-pressurize?
  5. Really have a lot of questions about transfer to the keg. Obviously the beer at that point will be more carbonated than fermenting w/o pressure.
    1. Do I need to transfer under pressure (kinda like a giant version of a counter pressure filler)? I'm concerned about foaming. I really have no clue about how this works. I figured I'd move the spunding valve to the gas port of the keg and set it to something just under the pressure in the fermenter. Say the ferm is at 10 psi, set the valve to 7 or 8.
    2. I currently transfer with siphon/gravity. I connect the output of the ferm to the liquid line of the purged keg. Then connect the gas line of the keg back to the fermenter for a closed transfer. Can I still do this if I have a pressurized transfer? If so, what's the best sequence of connections to make that work? I know I'll have to start with positive pressure (relative to the keg) to get flow going, but once I get some siphon action, I'm assuming they can reach equilibrium (pressure wise) and still work. I'd prefer not to use the CO2 from a tank to push the entire volume of beer to the keg if possible.
Anyway, those are some quick questions off the top of my head. I'm sure I'll have more.

I'd love to hear from anyone using a fermzilla (because it's a bit different than those with conicals that bottom drain), but any pressure ferm and transfer advice would be greatly appreciated.
 

Jtvann

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I’ll take a stab at a few of your questions. I bought a unitank a few years back. I thought pressure fermenting was something I wanted to do early on because with the equipment I finally could. I didn’t really understand why though. My reason for doing it was because I could and it was new and cool. My first point of advise is to all yourself why you want to do it.

1-it’s different for different beers. For IPAs I don’t pressure ferment much at all. I want the esters that are produced. I will close the valve after I dry hop so that any left over fermentation won’t blow aroma off. I’ve found that around 18-19 psi, when cold crashes will drop to about 12 psi. For me, that’s good for carbonation.

If I’m making a Lager, I can pressure ferment for the whole time. I close it right at the start and let yeast build to about the same 18 psi. You can ferment warmer doing this. It goes faster as well. Read more on the forums about different beers and the advantages and disadvantages of pressure.

2- I don’t add initial pressure from a CO2 tank. I let fermentation build all my pressure.

3- Pressure does hold krausen down some. It will still blow off of your fermenter is too full. I’ve never purged kegs from my fermenter but I could. I’d wait till about day 3 and hook it up just to be safe. Your setup sounds right.

4- Of you open to add dry hops to pressurized beer, you can get a beer volcano. Look up YouTube videos for beer volcano. If dry hopping it’s best to pressurized after adding dry hops unless you are doing an enclosed canister dry hop that can be equally pressurized. Again, IPAs ... you probably want the esters and shouldn’t pressure ferment initially.

5-1- you are correct on your setup. It’s a giant counter flow process. If you don’t have your keg pressurized it will foam.

5-2- You still want a closed system, but you will be pushing CO2 into the fermenter from your tank. Set your fermenter to maybe 10, your keg to maybe 8. Continue to push beer from your tank into your fermenter as beer flows.
 
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Hwk-I-St8

Hwk-I-St8

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@Jtvann - Thanks for your thoughts. IPA's are the initial driver and I had the same motivation: to retain hop aroma after adding dry hops. I'll google the hop volcano....sounds like something to avoid and the vids will likely be entertaining!
 

VikeMan

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IPA's are the initial driver and I had the same motivation: to retain hop aroma after adding dry hops.
If you're thinking you'll retain hop aroma due to more CO2 being retained in the fermenter, and thus less blowoff, it's a very small percentage of the CO2 produced. (Assuming typical temps, pressures, and head spaces.)
 

Gusso

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Although somewhat new at pressurized fermentations, I mostly do lagers with it. Or clean ales. I still do my hoppy ales in my Speidels.
 

dtashmore547

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I have just started with pressure fermentation, so only two brews to go by, my reason for pressure fermenting was that I am brewing in.the upper 20's to mid thirties so have tried kviek Oslo yeast and have been impressed with the results. I am using a 50 lt keg for 30 lt brew, I have welded a tap to the bottom and a pressure release valve to the top along with a pressure gauge and have run it at 30psi.
it works really well to transfer to a 30 lt keg by adding co2 to the gas in of my pressure vessels coupler and closing the beer out, the tap on the bottom of my pressure vessel delivers the ale to the beer out of the coupler on my keg whilst I have a tap fitted to my gas in to control the flow. the final result is fully gassed ale at my 10psi serving pressure, 30 psi certainly worked for me and no problem with foaming on the fill. hope this helps you
 
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