Closed-system pressurized fermentation technique!

Bumbler said:

I agree, get one that relieve pressure by itself.

Be very quiet!

Don't tell the anti-cornelius keg fermenters, but I primary in a corny keg and love it, add 2 drops per gallon and you can primary 4.5 gal. without worry.

I also fermented my last batch of AM. Amber under 12 PSI. in a corny. It's currently cold crashing, will transfer this weekend.

I got my relief valve from Grainger. Only $16 and maintained pressure very well. A few extra fittings from Menards and only took 5 Min to assemble.

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Would you mind listing the parts to your pressure set up.

Thanks

WortMonger said:

nbspindel is right about it taking about 10 minutes. I up the pressure like it was a sink valve handle. Start with both at the same pressures and when you increase the initial keg, the target keg will start filling. I eventually get to about 5 psi over target keg pressure in my initial keg after I have beer in the target keg. nbspindle is "right on" about watching the keg fill too, as it will start blowing the CO2 into the bottom of the target keg and will foam the beer up and out of your gas port once you are empty in the initial keg. Slow is the key to keeping your carbonation and not having a mess on your hands. You can also keep both kegs at the same pressure to start, and then lessen the pressure in your target keg. However, this isn't as safe a way to transfer as the first way mentioned. It is still a counter-pressure transfer, just not as easy to control as the first way. It will work though either way. I like my target kept at the pressure I want it to end up at, and raise the pressure in the first keg as control.

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Is this because you are transferring warm, carbed beer? I do the closed-transfer of carbed beer on all my lagers (which are cold) and I just lift the relief valve on the target keg and have never lost any carbonation (nothing significant anyway) or made a mess. I keep the 'send' keg at my typ serving pressure (~12-ish psi) for the first ~3/4 of the transfer and then pull the QD and let the residual pressure finish...with my hand poised on the target keg QD to prevent the gas from getting in when the send keg is empty.

I'm not sure if I should chill ales first before transferring or just transfer warm using your 'increase-send-keg-pressure' technique. I'm going to be trying to naturally carb an Oatmeal Stout in a few days using the Grainger adjustable RV lamarguy posted.

This topic came up yesterday while hanging around the LHBS. It's a technique I'd like to try on my next batch; at least on part of it.

My thinking is to equalize the pressure in the two kegs via gas inlets, then elevate the source keg and just gravity feed into the destination via the liquid outlets. It's the same concept as the counter pressure filler I've operated to fill bottles of carbonated wine.

I'm also interested in the grainger part # for the prv.

Here are two pressure relief valves from Mcmaster (my preferred vendor):

Brass Adjustable Vacuum/Pressure Relief Valve 0 - 20 PSI $8.32

Polysulfone Adjustable Pressure-Maintaining Relief Valve 0.5 - 30 PSI $30.13

I've experimented with both valves and I prefer the Polysulfone valve. It's more expensive, but is of higher quality, has a finer adjustment mechanism, and is available in a wider pressure control range.

lamarguy said:

Here are two pressure relief valves from Mcmaster (my preferred vendor):

Brass Adjustable Vacuum/Pressure Relief Valve 0 - 20 PSI $8.32

Polysulfone Adjustable Pressure-Maintaining Relief Valve 0.5 - 30 PSI $30.13

I've experimented with both valves and I prefer the Polysulfone valve. It's more expensive, but is of higher quality, has a finer adjustment mechanism, and is available in a wider pressure control range.

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Did you also compare those to the Grainger P/N you posted earlier itt? What did you not like about that one? I bought two of them and they look nice enough. I usually prefer McMaster too unless it's a motor but Grainger is close and they delivered it almost impossibly fast (as does McMaster...I dunno how they do it). I ordered it one morning and it was on my doorstep the following day (standard ground shipping).

SpanishCastleAle said:

Did you also compare those to the Grainger P/N you posted earlier itt? What did you not like about that one? I bought two of them and they look nice enough.

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I didn't mean to imply that either brass valve (Grainger or McMaster) is of poor quality, I was just stating my preference. After playing with a friend's Grainger valve setup, I feel the brass valves from Grainger and McMaster are both sufficient, just not the "best" due to the imprecise adjustment mechanism and lower pressure range (McMaster valve).

i've been thinking about bottle filling from a carbed keg (perhaps i should send this to the bottling forum?). if i loose carb next time i fill a bottle from my keg, i thought i would add some priming sugar or a coopers carb tablet. there should still be yeast from the keg, right? i might just have to let it warm up to room temp and condition for a while. I might end up overcarbing, though, i know. Good idea? Bad idea? I should just figure out the bottle filling technique

I would try to perfect the bottling technique. IME, the colder the better (bottles included but not frosted/frozen).

SpanishCastleAle said:

Is this because you are transferring warm, carbed beer?

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Nope, I do all my transfers as cold as I can get them. I just don't want the chance of losing any carbonation.

SpanishCastleAle said:

I do the closed-transfer of carbed beer on all my lagers (which are cold) and I just lift the relief valve on the target keg and have never lost any carbonation (nothing significant anyway) or made a mess. I keep the 'send' keg at my typ serving pressure (~12-ish psi) for the first ~3/4 of the transfer and then pull the QD and let the residual pressure finish...with my hand poised on the target keg QD to prevent the gas from getting in when the send keg is empty.

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As I mentioned, this way is fine. I ask you though, if your send pressure is 12 psi, then your target has to be less than that to have beer going into it. If you want 12 psi in your target, then you have to have it set at 12 psi and your send higher or beer wouldn't go into the target... or worse, back into your send from your target.

This is why I juice the send keg with the bottle and set my spunding valve to what I want my final pressure to be in my target keg. It is more of a one-way street with a known ending pressure in my target. I do have my target at a little lower than sending keg pressure to start the transfer, but with my spunding valve set to my wanted ending pressure. This insures I don't get a blast of CO2 into my sending keg before beer starts to flow into the target keg and stir up sediment (which happened while learning my system). It is fine to have nothing but a purged target keg, with no pressure, and then start your transfer from your sending keg... but you will get more sediment & foam due to the increased speed of transfer initially until your pressure starts to raise in your "filling" target keg. Once the pressure in your target hit your "set spunding valve pressure" you would be maintaining pressure. Once again though, you did lose a little carbonation all-be-it minimal with ice cold beer.

I just feel, why chance it? If my target spund is set to 12 psi at room temperature and my bottle is pushing 15 psi into my sending keg, it takes very little before I am at 15 psi in both kegs. The little bit of fast beer at the first has time to settle down so foam isn't ever a problem, and I haven't lost hardly any CO2 if any at all.

SpanishCastleAle said:

I'm not sure if I should chill ales first before transferring or just transfer warm using your 'increase-send-keg-pressure' technique. I'm going to be trying to naturally carb an Oatmeal Stout in a few days using the Grainger adjustable RV lamarguy posted.

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I just transfer after my crash cool so that I have the beer where I want it. If you don't crash a beer and you stay at a higher temperature, then I would just use a higher pressure to transfer (based on what pressure you wanted at whatever temperature). There are lots of ways to skin a cat, what works for you... works for you, so go with it.:rockin:

Vinic said:

This topic came up yesterday while hanging around the LHBS. It's a technique I'd like to try on my next batch; at least on part of it.

My thinking is to equalize the pressure in the two kegs via gas inlets, then elevate the source keg and just gravity feed into the destination via the liquid outlets. It's the same concept as the counter pressure filler I've operated to fill bottles of carbonated wine.

I'm also interested in the grainger part # for the prv.

Click to expand...

Curious as to how this would work? How would you start the gravity siphon (knowing that once it was started the gas in the filling keg would go to the growing headspace in the source keg)? Would the source keg have initial pressure like a serving keg would, and the target keg just be purged with no pressure so as to start beer up the dip tube when you connected the beer ports? Once the transfer had started, would you then hook the gas ports together? Wish you could draw it out for me, or explain in more detail. Very interesting idea.

Hugh_Jass said:

Would you mind listing the parts to your pressure set up.

Thanks

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I'll keep it short.

Mine is 3/8" because that's size of the barbed fitting and tubing I had lying around but I think 1/4" would work just as well.

Short piece of tubing.
3/8" barbed X 3/8" MPT
3/8" Female T
90 elbow 3/8" MPT X 3/8" FPT
Pressure relief valve of your choice. Listed and linked 6 posts above.
3/8" X 1/4" reducing bushing
0-30 PSI pressure gage

Sounds like you guys are wasting a lot of CO2 during the transfer process. My guess would be that it's more economical to ferment under pressure, but skip the carbonation phase at the end of the process. Then force carbonate later.

The advantage would be that you don't have to go through the hassle of counter-pressure transfer. You would apply a light pressure from the bottle ~3-5PSI on the primary keg, transfer to the target keg with little foaming, then purge the headspace in the target keg and force carbonate like usual.

When you're done, this way you only have your primary keg of wasted gas @ 3-5PSI, not 15PSI.

GNBrews said:

Sounds like you guys are wasting a lot of CO2 during the transfer process. My guess would be that it's more economical to ferment under pressure, but skip the carbonation phase at the end of the process. Then force carbonate later.

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Not sure what you're saying. Fermenting under pressure IS carbonating.

For example, I'm about to transfer a stout fermented at 10 PSI that I cold crashed this morning at 30F. The pressure dropped to ~6 PSI (due to the temperature change) this afternoon and I plan to transfer at ~8 PSI. I've retained natural carbonation, not lost it.

I think you're missing my point. What I'm saying is that fermentation under optimal pressure won't carbonate to the usual levels that most of us carb our beer to unless you close the spunding valve at the end of fermentation and let the pressure climb quite high. Fermentation at 5-7PSI at 65F isn't going to give you the 2.5vol of CO2 most of use enjoy as a final carbonation level.

If you carbonate to 2.5vol, counter pressure transfer (and the associated waste of gas) becomes necessary to maintain that carbonation level.

GNBrews said:

I think you're missing my point...Fermentation at 5-7PSI at 65F isn't going to give you the 2.5vol of CO2 most of use enjoy as a final carbonation level.

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Correct, it gives you partial carbonation (1 - 1.5 volumes).

GNBrews said:

If you carbonate to 2.5vol, counter pressure transfer (and the associated waste of gas) becomes necessary to maintain that carbonation level.

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So long as the beer is cold (< 38F) during transfer, you're not going to lose much carbonation. For example, I chill my beer to 30F and transfer under ambient pressure (no counter pressure). I get negligible foaming.

So what I have been doing is simply bumping up the spunding valve to about 30 PSI with only a little fermentation to go. This should carb it to ~2.5 volumes right?

Is there a down side to this?

The question I have always has to do with yeast harvesting? I've heard that a sharp change in pressure kills the yeast. So when I crash cool the beer it should drop the pressure to roughly serving pressure. I then pressure transfer to serving kegs. Can I still harvest the yeast or is the pressure change from 12 PSI to 0 going to kill them?

aarondrich said:

So what I have been doing is simply bumping up the spunding valve to about 30 PSI with only a little fermentation to go. This should carb it to ~2.5 volumes right?

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Yup, 30 psi is ~2.5 volumes at 67F.

aarondrich said:

Is there a down side to this?

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According to the literature, once you pass 1 bar (14.5psi) of top pressure the yeast behavior will change significantly. For example, the acetaldehyde (green apple) production increases exponentially and the sugar consumption rate will slow. So, you really need to be sure the terminal gravity is within 1 or 2 points before you pass 1 bar.

aarondrich said:

Can I still harvest the yeast or is the pressure change from 12 PSI to 0 going to kill them?

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Breweries harvest yeast under pressure on a regular basis. The key is a slow change in pressure to avoid a sudden release of CO2 from the yeast cell wall. Otherwise, the yeast will literally implode.

Slow over how long?

So if you don't carb it all the way and leave it at 5-7 PSI, the advantages are what?

Faster Fermentation?
Less Off Flavor Production?
Oxygen Free Transfer?

Am I wrong or missing anything?

aarondrich said:

Slow over how long?

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I don't have a good answer.

Anecdotally, the head brewer at Real Ale mentioned it takes about an hour to equalize their clearing/racking tank (where the yeast is harvested) to ambient pressure. Since I don't know the starting pressure, it's hard to say. With that said, many breweries store their yeast under partial pressure (e.g. 2 psi at 34F).

aarondrich said:

So if you don't carb it all the way and leave it at 5-7 PSI, the advantages are what?

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I listed the primary advantages (according to the literature) earlier in this thread.

Here's an action shot from last Saturday when I coarse filtered (5 micron nominal) my London Porter straight from the fermenter.

I cold crashed to ~30F to promote yeast flocculation and prevent foaming, purged and pressured the destination keg to 6 psi (via the spunding valve "dongle"), and maintained 9 psi in the fermenter (via the small CO2 tank). With a 3 psi pressure differential, it took about 15 minutes to rack and filter 5 gallons of carbonated beer (2.5 volumes). No foaming whatsoever.

In the future, I plan to experiment with dry hopping in the same filter housing using a coarse filter. Sparkling beers will get an absolute 1 micron filtration experience. The filters are reusable numerous times, so I'll likely start filtering on a regular basis.

Lamarguy, so did you jack up your spunding valve at the end of fermentation like we discussed earlier in the thread to get to 2.5 volumes? If so at what point?

aarondrich said:

so did you jack up your spunding valve at the end of fermentation?

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Pressure steps (by day):

1. 1 psi @ 66F
2. 2 psi @ 66F
3. 4 psi @ 66F
4. 6 psi @ 66F
5. 12 psi @ 69F

After I cold crashed to 30F, that left me with ~2 volumes of CO2 (pressure gauge read 3 psi). I then applied 7 psi of top pressure for 48 hours @ 30F to reach 2.5 volumes of CO2 in the fermenter.

lamarguy, how do you store your filters after use? Do you clean and then store? What's your technique?

WortMonger said:

lamarguy, how do you store your filters after use? Do you clean and then store? What's your technique?

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1. Disassemble the housing and rinse off the excess beer.
2. Soak everything in a ~120F PBW solution (oxyclean is fine) for 30 minutes.
3. Reassemble everything and back-flush the filter using tap water pressure.
4. (Optional) Sanitize the filter using a non-staining/non-acidic sanitizer and allow to air dry. I use a commercial quat, same thing I use for sanitizing kegs.

Before each use, I give the dry filter a quick dunk is a no-rinse quat solution.

1 micron filter
5 micron filter

I've been reading the WIKI on lagering and there are charts that reference pressurized fermentation for lagering too? The wiki assumes that this isn't an option for home brewers, but obviously for this crowd that may be wrong. I was just curious if people have played around with this, and was curious as to what their schedule/process looked like?

I would love to try a lager since I have controlled fermentation temperature as of yesterday.

Thanks in advance!

aarondrich said:

I've been reading the WIKI on lagering...I was just curious if people have played around with this, and was curious as to what their schedule/process looked like?

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Sacc posted earlier in this thread about his successful pressurized lager experiment. I tasted this beer and it was pretty clean, other than an green apple (acetaldehyde) note.

The key is to not raise the pressure higher than ~1 psi for the first 24 - 36 hours (36 hours for a 48F lager) and not got above 1 bar (14.5 psi) after that. Otherwise, yeast growth will likely be retarded to the point the beer may not fully attenuate.

you guys are my hero, I need to get this going. I was wondering if you guys dry hop in your serving keg then. I see lamarguy wants to do so during the filter.

Also, how are you not picking up any trub or is that another benefit of using a filter?

I am new to this whole thing, but made an IPA as my first pressurized fermentation and did dry hop in the keg. Since it's carbonated already, the hop addition makes a lot of foam so be quick!!! I bought one of those large herb balls and put 1 oz of hops in it and it just sank to the bottom. I've read mixed replies as to whether or not this gives a grassy flavor, but I didn't have any available method to pull it out that day. So far so good, it's been in there a couple of months and tastes great.

Lamarguy, just to clarify, do you believe that keeping the first 36 hours at less than 1 PSI and also the total Pressure to under 14 PSI that it will eliminate the green apple taste?

aarondrich said:

Lamarguy, just to clarify, do you believe that keeping the first 36 hours at less than 1 PSI and also the total Pressure to under 14 PSI that it will eliminate the green apple taste?

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The aceteldehyde production rate is a characteristic of a particular yeast strain. So, two different yeast strains will produce differing amounts of green apple ester (regardless of top pressure). However, increased top pressure does increase aceteldehyde production in all yeast strains.

Sorry, I don't have a good answer for you because I haven't experimented with lager yeast under pressure (yet). I posted some of the pros/cons for pressurized fermentation earlier that may be of some help.

Thanks for the info, I'm just trying to learn. I would love to do some lagers and it seems like this may be the way to go. I only have 1 fermentation chamber, and while it will get down to lagering temps, some schedules take like 2 months? This seems like a way to have things done in roughly 2 weeks if I'm reading things correctly.

humann_brewing said:

You guys are my hero, I need to get this going.

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Ha, Wortmonger is Captain Nemo...He's the hero 'round here.

humann_brewing said:

Also, how are you not picking up any trub or is that another benefit of using a filter?

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I use a combination of cold crashing (30F) and a racking cane tip (on the adjustable racking arm) to avoid trub pickup. On the last couple of batches, I only lost ~1/4 gallon to trub loss.

At or below 32F, 99% of the biomass load drops out of suspension forming a compact "cement" that contains the cold break quite well. The minuscule percentage that slips by will be caught by the 5 micron filter.

My next experiment is with "ice stabilization". Fix writes that 3 - 5 micron filtration produces a very flavor stable beer. However, ice stabilization at 28F produces the best known flavor stability and only results in a 2% loss of water (due to ice crystal formation). According to Fix, the order of flavor stabilization techniques is (least effective to most effective):

1. finings (PVPP, gelatin, etc.)
2. 1/3/5 micron filtration
3. finings + filtration
4. ice stabilization + filtration

Interesting... Ice Stabilization??? My interest has been peaked

aarondrich said:

This seems like a way to have things done in roughly 2 weeks if I'm reading things correctly.

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Using this technique, my ales (< 1.070) are on a 14 day schedule but I can see a lager (< 1.060) requiring an additional 1 - 2 weeks of lagering (~45F) time before its flavor is "ideal". Notice that I halved the recommended lagering time based on the assumption the pressured fermented beer has a lower overall ester profile.

Realistically, 21 - 28 days for a lager but still much shorter than 2 months.

Out of curiosity, what does "Lagering" at 45 do that just conditioning the beer at 65 does not? The beer at this point is fully attenuated correct?

aarondrich said:

Out of curiosity, what does "Lagering" at 45 do that just conditioning the beer at 65 does not?

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I recommend you start a new thread if you have questions about general lagering techniques. I'm not trying to ignore/bump you, but it's really not relevant to pressurized fermentation.

From the link I posted earlier:

A common question is, "If the beer will lager faster at higher temperatures, why would anyone lager at the low temperature?" Two reasons: first, in the days before refrigeration when lager beers were developed, icehouses were the common storage method - it's tradition. Second, the colder lagering temperatures seem to produce a smoother beer than warmer temperatures. This would seem to be due to the additional precipitation and settling of extraneous proteins (like chill haze) and tannins that occur at lower temperatures.

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I agree with lamarguy about keeping this thread as clean as possible, but only because it is getting so long people aren't reading everything in it.

aarondrich, thanks for the interest . I will be reading your thread on lagering .

Now... for all you guys (lamarguy and others) with the further knowledge from papers written and actually using this process on stuff like lagers... add to my wiki article PLEASE!!!! LOL, I need to update it anyway, and a simple word file with your changes to my original would be greatly accepted. I'll do the work and cite you if you don't know how to wiki. I like this thread, but the wiki is a better way to explain it in one page for everyone. God, I never imagined I'd have a thread this massive. I don't even want to go back and read the whole thing, lol. Seriously though, thank you guys and keep it up!!! Make daddy proud, lol. I'm learning so much... and it's my thread. Cheers

hey wortmonger,
would you be able to expand on the section on reusing the yeast cake? i understand how you pour pre-boiled water onto the cake, re-tap, and then clean using the provided link. Have you ever just poured new wort directly onto the remains in your secondary keg? I'm thinking the next two brews i'll do will use the same yeast. after transferring brew 1 from the secondary to the serving keg, i would be boiling brew 2 to pour right onto what's left in the used secondary keg. What i worry about here is any junk left around the sides of the keg giving off flavors. Or does anyone think it's possible to put a second brew right onto the yeast and trub left over in the primary? I think that's a worse idea because of the trub.

thanks for your thoughts.

Warning - Always provide a route for excess pressure to escape the keg when experimenting with pressurized fermentation. A sudden, violent release of pressure can kill!

Case in point, don't forget to connect the tap. Otherwise, the keg pressure will reach 60+ psi.