Fermenting Under Pressure

[pcqypcqy]

One fermenter yes, one no. I have yet to identify a major difference.

This might be a winner. I've found even solid yeast cakes can give me issues on the transfer, but I want to keep my options open for large or small batches and try to get as much beer off the cake each time.

I've already cut 20mm off mine, which works OK for a 5 gallon batch. I was going to cut more to make easier transfers on the larger batches.

 

[pcqypcqy]

Might try this approach I have two 26 litte kegmenters and will make roughly 21 litre batches so should be able to get the hops in without it being a gusher if I keep pressure to between 10 to 15 psi. Are you letting your hops in the stocking sink to the bottom or suspending with something like floss? Great info mate

No floss - I find that they will float on their own, but like an iceberg some portion will be out of the beer which seems inefficient to me.

So I throw an unused stainless disconnect or keg part (depending on what I have around) in the stocking with the hops to submerge it some. I'd say they're still floating after I do this.

 

[Gloveski]

Haven't even used mine yet and Im alreay thinking of a mod. A conical set up to dump trub and capture yeast would be awesome . Something simular to blichmann's cornical but I wouldn't be interested in turning it into a keg .

 

[pcqypcqy]

Haven't even used mine yet and Im alreay thinking of a mod. A conical set up to dump trub and capture yeast would be awesome . Something simular to blichmann's cornical but I wouldn't be interested in turning it into a keg .

How would you attach it? If you're talking a custom welds, would you be better off hacking into some old kegs and attaching some kit pieces?

 

[rossbaker]

Is anyone doing this in 19l corny kegs? This is my plan, let me know what you think.

Brew 34litre batch, no chill in 2 x 17l cubes, ferment these in 19l corny kegs, either with a blow off or a spunding valve or both.

Questions:

Will that be enough headspace? Im planning to use fermcap s.

Can the beer just be served from the same keg once the yeast is transferred out or does it need to be transferred to a serving keg? I have tried this with a small batch wheat beer but I wasn't so fussed about that being bright.

Tring to avoid the cost of buying 2 ibrew kegmenters for a while...

 

[pirateagenda]

don't worry about the cubes. just transfer straight to sanitised corny's then purge the head space with co2. Then when they have cooled and you're ready to pitch, release the c02 and oxygenate the wort and pitch yeast.

17L should be ok with fermcap in a 19L keg. you could hook them both up to a 3rd keg from both gas posts to tee to liquid in on the 3rd keg to avoid messy overflow and only need 1 spunding valve.

 

[pcqypcqy]

I think the yeast thing is probably not an issue on small scales and quick turn arounds. If you were leaving that beer in there for months and months, it might not be so great. The yeast may also clog up the dip tube.

Apparently there's also an issue with imploding corny's when you cold crash, though if your warm pressure is positive then you should be OK. I think this is an issue when you no-chill into a corny prior to ferment - you will get a decent negative pressure from the cooling of the wort.

 

[rossbaker]

don't worry about the cubes. just transfer straight to sanitised corny's then purge the head space with co2. Then when they have cooled and you're ready to pitch, release the c02 and oxygenate the wort and pitch yeast.

17L should be ok with fermcap in a 19L keg. you could hook them both up to a 3rd keg from both gas posts to tee to liquid in on the 3rd keg to avoid messy overflow and only need 1 spunding valve.

I have thought about that and my only concern is my current lack of an O2 setup. I imagine I would need to pressurise to a fair degree with co2 to counteract the vacuum effect of cooling and avoid the imploding corny pcpypcpy mentioned. Without the ability to directly feed O2 back in would this have a bad effect on fermentation?

 

[pirateagenda]

I have thought about that and my only concern is my current lack of an O2 setup. I imagine I would need to pressurise to a fair degree with co2 to counteract the vacuum effect of cooling and avoid the imploding corny pcpypcpy mentioned. Without the ability to directly feed O2 back in would this have a bad effect on fermentation?

no just bleed off the c02, open the lid and give the wort a good shake up or aerate as you normally would.

 

[Gloveski]

How would you attach it? If you're talking a custom welds, would you be better off hacking into some old kegs and attaching some kit pieces?

Yeah not really sure I'll leave it a while yet and look more into it down the track

 

[Maximus Humulus Lupulus]

Okay, this is my first post on this esteemed forum, and being based in England this is the furthest south I’ve ever posted, so be gentle with me!

I’ve been having great fun fermenting under pressure with the Fermentasaurus, which has only been available in the UK for a few months. (I like it so much I bought two.)

I’m on my fourth brew (a Galaxy/Citra IPA), and to date have been fermenting at 10-12psi, which I find works well (especially as that’s the serving pressure I use in my kegs).

Being a newbie to fermenting under pressure, my reason for posting here concerns dry hopping under pressure.

I’m not a big fan of using the collection vessel to introduce hops, as I don’t like the idea of oxygen bubbling up through my beer, and on the Fermentasaurus the collection vessel is too small for the 150g to 500g dry hop quantities I use (the manufacturers recommend only 30g at a time).

Much better to release the pressure, spin the lid off and add dry hops the traditional way, from the top. Screw the lid back on and fully purge with CO2 a few times, repressurise, and job done. Takes mere seconds. That seems to me to be more sensible than having oxygen bubbling up through the beer via the collection vessel method, which I feel is the Achilles heel of all the current crop of conical plastic fermenters.

Where was I....? Ah, yes. Thanks to the this FV’s clear PET construction, I’ve been able to observe what happens to the dry hop (pellets) under pressure, and have noticed that when I repressurise back to 10-12psi immediately after adding the dry hops, the little buggers sink straight to the bottom like stones. If I back off the pressure to around 5 or 6psi, they float back up to the top.

I’m guessing that the greater the internal pressure, the more force is acting on the hops, which pushes them down. I could be wrong. I was crap at science at school. Or I may just have extra heavy hops!

Whatever the reason, I’m thinking that it’s much better to allow your hops to absorb beer and gradually sink to the bottom naturally, dispersing aroma and flavour compounds as they go, than to be packed densely in the bottom of a cone from minute one, where they’re having minimal exposure to the beer.

I’d be interested to hear your thoughts on this, as I know from reading through this thread that many of you ferment at 15psi and above, as indeed do some commercial breweries. That said, some breweries also have the ability to agitate hops in the FV to reduce dry hopping time and maximise aroma/flavour, so this isn’t an issue for them.

Over to you folks!

 

[Mardoo]

I think it was Vinnie Cilurzo from Russian River, but it may have been Stone, that commissioned a laboratory study about dry hopping and pellet suspension. It showed that pellets that suspend the longest have the highest transmission of hop flavour compounds. Having spent a fair bit of time packing hop pellets in a friend's business, there are major differences in pellet density between processors, from practically glassy through to almost spongy. Unfortunately, hop growers do not always have control over what sort of pellets the processors they use produce. However, I know that some of the new craft hops growers intentionally aim to produce a looser pellet. So in terms of suspension, you're on the right track. Can you bubble CO2 up through the hop and yeast mass from the bottom of the Fermentasaurus? That's the easiest way to re-suspend.

I can't speak to floatiness of pellets under pressure, because I ferment in a stainless pressure vessel. However I do re-suspend daily with a CO2 injection through the liquid out post, and a solid shake. I then re-equalise the pressure to my desired level. I usually ferment at 10psi, as I'm usually not looking for ester suppression.

Generally when I dry hop, rather than open the fermentation vessel I put the hops in another of my SS fermenters, purge, and transfer the beer through the liquid posts. I'm not always organised enough to have one of the fermenters ready, but try to be.

 

[bradsbrew]

If you crush the pellets up they will float for a little while before slowly dropping to the bottom.
I have found that if you drop a fair amount of pressure through the prv, it will stir what is sitting low and it rises to the top and helps to suspend until it settles again or it is repressurised.

 

[Lionman]

Is anyone doing this in 19l corny kegs? This is my plan, let me know what you think.

Brew 34litre batch, no chill in 2 x 17l cubes, ferment these in 19l corny kegs, either with a blow off or a spunding valve or both.

Questions:

Will that be enough headspace? Im planning to use fermcap s.

Can the beer just be served from the same keg once the yeast is transferred out or does it need to be transferred to a serving keg? I have tried this with a small batch wheat beer but I wasn't so fussed about that being bright.

Tring to avoid the cost of buying 2 ibrew kegmenters for a while...

I ferment in 19L kegs filled to the top. I connect a line from the gas post (I cut the dip tube down so it doesn't protrude into the keg) to the liquid post of a mini keg and attach the spunding valve to the gas post of the mini keg. I have done quite a few batches like this and most I lose in blow off is a few hundred mls. When I transfer to the serving keg it pretty much fills it up. Beer comes out of the pressure relief valve at the same tim the fermenter starts suckking gas. I put a tee on the blow off so i can have two kegs fermenting into one blow off.

The kegs I ferment in are not cornies though, they are chinese kegs I picked up cheapish and I think they hold a little more than a cornie.

I don't bother with adding chemicals to beer. Water+Grain+Hops+Yeast.

 

[Lionman]

I’m guessing that the greater the internal pressure, the more force is acting on the hops, which pushes them down. I could be wrong. I was crap at science at school. Or I may just have extra heavy hops!

I'm not sure pressure would have much impact on buoyancy of hops. Buoyancy has to do with the difference in volumetric mass density between the liquid and the object that is floating. The volumetric mass density of beer and hops won't change under CO2 pressure, or at least very little, and not enough to have a significant impact. The amount the hops are compressed prior to putting them in the fermenter will have a much bigger impact as while co2 can not compress hops (increase their volumetric mass density), a hop pelletising machine can.

It may even have the opposite and make hops more buoyant because as you push CO2 into solution you are actually making the beer more dense. it is taking up the same volume but you are adding the mass of the co2 to that volume making it more dense. I'm not sure the hop matter would absorb much CO2 being a solid? Maybe hop oils absorb co2 Any affect either way is likely to be negligible.

 

[bradsbrew]

Just went out and took a video of a brew i pitched yesterday.

 

[Mr B]

Perhaps the pressure compresses any air in the pellets enough to make them sink

 

[Danscraftbeer]

I think I'm glad I have a Steal fermenter. If I had one of those Fermentsauruses I'd get captured to who knows how many hours watching it.

 

[Gloveski]

I think it was Vinnie Cilurzo from Russian River, but it may have been Stone, that commissioned a laboratory study about dry hopping and pellet suspension. It showed that pellets that suspend the longest have the highest transmission of hop flavour compounds. Having spent a fair bit of time packing hop pellets in a friend's business, there are major differences in pellet density between processors, from practically glassy through to almost spongy. Unfortunately, hop growers do not always have control over what sort of pellets the processors they use produce. However, I know that some of the new craft hops growers intentionally aim to produce a looser pellet. So in terms of suspension, you're on the right track. Can you bubble CO2 up through the hop and yeast mass from the bottom of the Fermentasaurus? That's the easiest way to re-suspend.

I can't speak to floatiness of pellets under pressure, because I ferment in a stainless pressure vessel. However I do re-suspend daily with a CO2 injection through the liquid out post, and a solid shake. I then re-equalise the pressure to my desired level. I usually ferment at 10psi, as I'm usually not looking for ester suppression.

Generally when I dry hop, rather than open the fermentation vessel I put the hops in another of my SS fermenters, purge, and transfer the beer through the liquid posts. I'm not always organised enough to have one of the fermenters ready, but try to be.

When you dry hop mate and transfer are you then using this as your serving keg ? If you transfer again are you loosing any aroma from the spunding valve venting during transfer on the receiving keg

 

[Gloveski]

The keg king float balls worked a treat in my kegmenters . all that was left was a nice yeast cake