Fermenting under pressure

[PhilboBaggins]

Hi everyone.

Thought I'd make a thread to discuss pressure fermenting so that we can have a handy place for tips and "gotchas" like my hop volcano from yesterday.

This is my very first fermentation under pressure so I was unprepared for losing the precious hops up the sides on my second dry hop when they hit the foam, especially since the bio-T charge didn't result in the same thing happening. I'm not convinced I lost a significant amount, but still, I'd rather avoid it.

My pressure at the time was 7.5 PSI. I am wondering if the second hop charge a couple of days later was just that little bit later on and that more CO2 was in solution.

Does anyone have any advice on this issue or any other issues you have solved with pressure fermentations?

Thanks.

Phil

[Titan]

I have seen but not used the following method for fermentasaurus. Get a few of those metal hop balls (strainers) and a few magnets load them up with hops and fix to inside of fv with the magnets. When your ready to dry hop just remove a magnet. 

[PhilboBaggins]

47 minutes ago, Titan said:

I have seen but not used the following method for fermentasaurus. Get a few of those metal hop balls (strainers) and a few magnets load them up with hops and fix to inside of fv with the magnets. When your ready to dry hop just remove a magnet. 

I've seen that, and it looks like a great idea if you're a fan of restrained dry hopping. You get so much more aroma from letting them cruise around at will in the beer though I have been led to believe.

[Titan]

Hope it a free article. https://byo.com/article/pressure-capturing-co2-fermentation/

[Marty_G]

I am quickly forming the opinion that if the the anti-oxidation benefits of pressure ferment and dry hopping are wanted,  best to do closed transfer to a secondary container like a cornie which has the hops in it.  Will need some extra gear like another floating dip tube. The magnets sound like a cool idea though and the conical fermenter has loads of head space. 

 

[PhilboBaggins]

Okay, so I went to take my first gravity reading last night and had a hell of a time getting anything to come out of the picnic tap. I reckon the floating dip tube is clogging with hop debris. My friend reckons he gets past this by blasting CO2 back through the liquid post and trying again. My attempts failed last night but I'm gonna have at it again tonight.

I'm confident she's nearly done so the D rest is underway.

I'll try again over the weekend, but if it's too hard I'll just CC and do the reading when the hops drop.

[Marty_G]

22 minutes ago, PhilboBaggins said:

I reckon the floating dip tube is clogging with hop debris.

I had a similar issue however, it was not as extreme as I used whole hops when I dry hopped.   I found a bit of a shake dislodged it.  I have also had issue when transferring with the floating dip tube sitting in the wrong position and not being below the liquid level so gas has come into the brew and through the liquid dip tube. It was not really an issue as it helped purge the head space but nonetheless not totally seamless and I have had to move and shake the fermenter a bit which has mixed the trub up a bit. 

 

Edited March 13, 2020 by MartyG1525230263

[PhilboBaggins]

40 minutes ago, MartyG1525230263 said:

I had a similar issue however, it was not as extreme as I used whole hops when I dry hopped.   I found a bit of a shake dislodged it.  I have also had issue when transferring with the floating dip tube sitting in the wrong position and not being below the liquid level so gas has come into the brew and through the liquid dip tube. It was not really an issue as it helped purge the head space but nonetheless not totally seamless and I have had to move and shake the fermenter a bit which has mixed the trub up a bit. 

 

That's good advice. I'll try and look through the crap and see where the tube is sitting.

[ChristinaS1]

There is fermenting under pressure and then there is dry hopping under pressure. The former is easy, the later is tricky.

Since my own experience with foaming out of the keg when I tried to dry hop on day 2 I have watched several YouTube videos, looking for solutions. All of the videos featured PET conicals so you can clearly see what is going on inside the FV, which is quite dramatic. The trick seems to be to release the pressure slowly and allow time for the foam to settle down before opening the lid. Even so it is important to add the hops quickly and get the lid back on as fast as possible, as more foaming may occur. I guess the hops are basically acting like thousands of nucleation points. But I doubt that method will work for kegs, which don't have the massive headspace of conicals. I think that with kegs the dry hops either have to be added 1.) before pressure builds up, or 2.) after the CC. I know the later works because I did it with my last brew. I have not yet tried the former.

So far I have only used pressure fermentation to brew lagers. I read somewhere that it is at around the 10 hour point that the yeast start producing fusel alcohols, so that is when I have begun applying pressure....At some point I will try fermenting a NEPA under pressure, but I am still trying to figure when to start adding pressure to ales. One video I saw said that if esters are desired, wait with applying pressure until fermentation is a few points away from final gravity, drying hopping immediately beforehand. Since the yeast would still be active they will scrub the oxygen introduced with the hops. I like ale esters and will probably try this method....I am guessing that if the hops are contained, you could fish them out after the cold crash without causing an overflow. One potential negative of this approach is that you would need temperature control for fermentation, which is not an issue for me but might be for some people. 

Cheers,

Christina.

Edited March 13, 2020 by ChristinaS1

[ChristinaS1]

This guy is kind of annoying, so don't watch the whole video, but if you want to see a boil over, watch from 10:30-12:00 minutes.

 

Edited March 13, 2020 by ChristinaS1

[Marty_G]

My latest brew was pitched with harvested Notts at around 2.30pm yesterday and has been sitting at ambient since then it is now close to 10 am and it is now at 5 psi @23C. The spunding is set for 12.5psi and should start releasing at some time today. I will monitor the temp but the forecast is for mild weather for the next 6 days with max around 26 and mins around 18. So this will more than likely be done at ambient for the duration.  Not sure if i will dry hop but if I do it will be when ferment is over and before the CC.  

 

6 hours ago, ChristinaS1 said:

This guy is kind of annoying

Watched a good part of the clip, interesting the guy used 300g of hops in that brew and waited 3 months to taste it. No wonder he lost so much of the hoppiness.  One thing for certain if I ever get a clear conical I will not add hops like he did in the 1st example. That would just piss me right of.  All the hops were commando yet his final beer was very clean wonder what he did to clear it. I suppose it is just be a good cold crash and emptying the collection jar on the conical a couple of times. Use of some finings and then a pressure transfer.   He used 10% wheat in the beer yet no cloudiness at all. I find my beers with wheat a bit cloudy.  

[Marty_G]

Well this is the pressure ferment that I kegged yesterday. It is cloudy as there is quite a bit of yeast in it due to issues with the floating dip tube but apart from that 8 days from kettle to glass and it is carbonated no problem. It is a Fat Yak pale ale clone, tastes great.  So pitched with a harvested starter of US05 on Friday. Saturday morning was at 12.5psi and the spunding valve was letting off a huge amount of gas. Ferment over on the Monday. Crash on the Wednesday and then kegged late yesterday, Friday,  and set at serving pressure. One week and into the keg.  It was not dry hopped but had 180g of late addition hops from 15 minutes, FO and hop stand.  So the hops are jumping out of it.  It is a really good beer. Very clean and good hop flavour. 

[Marty_G]

Another thing I have noticed is there is a discrepancy with hydrometer readings.  I have noticed that the FG of the sample that has been fermenting in the hydro tube is lower than the SG samples taken from the fermenter. I assume that this is due to the FG samples from the fermenter being carbonated and if left to sit and de-carbonate the FG would fall to match the non carbonate sample.  

[Shamus O'Sean]

Hi @MartyG1525230263, Are you thinking this because the carbonation causes the hydrometer to float a bit a give a higher reading?  The FG itself should not change between carbonated or flat, should it?  I am interested to know your thoughts because your statement is not in keeping with your technical brewing knowledge, so maybe there is something else going on I have not considered.

Cheers SOS

[Marty_G]

1 hour ago, Shamus O'Sean said:

because the carbonation causes the hydrometer to float a bit a give a higher reading

Yep that is my thoughts.

When I took the FG from the fermenter with my last completed brew I did not leave it to stand and de-gas. So I thinking that is the reason for the difference. I am sure the sample that fermented out in the tube is the correct FG.

Will prove it when I take a sample from the fermenter to test FG in a day or so. Will use a different tube, let the sample de-gas and do a side by side with the same hydrometer with the 2 samples. That is the one I took yesterday morning and the one I will take on Tuesday.   Both samples should be the same.   Gee I hope that makes sense. 

Edited March 15, 2020 by MartyG1525230263

[Marty_G]

@Shamus O'Sean well there you go proof is in there. Two different samples one that has been sitting at ambient since Saturday morning and the other taken out of the pressure ferment this morning and allowed to sit and de-gas.  Both the same reading and very close to expected of 1011 using Notts.  The crisper of  the two picks with the red canister in the right background is the de-gassed sample. 

[iBooz2]

On 3/13/2020 at 2:51 PM, PhilboBaggins said:

That's good advice. I'll try and look through the crap and see where the tube is sitting.

Yes you are bound to get some crud in the floating dip tube pickup even when not dry hopping commando.

What I have been doing recently just prior to bottling/kegging is this.

With the CO2 bottle tap turned on and set to serving pressure (as it’s normally connected to a keg), disconnect the CO2 from the keg then turn CO2 bottle tap off.  This leaves a 10 – 12 psi resident pressure in the gas hose.  Connect it up to the floating dip tube line and the resultant puff of CO2 clears the floating dip tube plus it will tell you where its actually sitting.  Note I only have pressure in the range of 5 – 7.5 psi in the FV by this stage as CC causes a pressure drop so the puff technique works well.

Once dip tube has been purged, remove the gas line, remove spunding valve, connect the gas up to the gas port and turn on the gas bottle tap back on to top up the pressure in FV to 10 - 12 psi, this is in readiness for the closed circuit transfer to keg.

Cheers - AL

Edited March 16, 2020 by iBooz2

[iBooz2]

Last time I harvested the yeast from the collection bottle on the fermzilla it ended up very messy and probably a very unsanitary process even though the pressure was released just prior.  So I had a bit of a think about it this time around and this is what I came up with. 

I used the cold crash plus top up pressure of 10 psi to transfer the beer into 12 x 345 ml stubbies and the remainder was transferred to a keg using the closed loop process which is where the CO2 from the keg gets fed back into the fermzilla as the beer get gravity fed into the keg.

I fill the 12 stubbies first to ensure this beer is nice and clear as they are used for travellers and test tastings for guest drinkers and leaves just a nice amount for the keg as the floating dip tube will run dry before the keg is full which leaves just a nice headspace.

The next step using whatever residual pressure remains in the fermzilla (my guess, about 2.5 psi) is to harvest the yeast via the red port that I had pre-fitted to the collection bottle.  This is achieved with a short length of hose and a ball lock connector into my storage jar (see pic).  All been sanitised of course.

Yeast and hop matter are fairly well separated, as you can see in the next pic, all the hop matter has settled below the red port and will not get transferred.  I could probably draw off 2 jars but one is enough for the next couple of brews.  This is a pic after 25 g of galaxy were commando dry hopped way back on day 3 of ferment and once ferment done then 7 days of CC.  The yeast is Windsor.

The real beauty of this process is absolutely no mess and by far a less risk of contamination of the transferred yeast.  Only a few drops to wipe up then the whole vessel is taken out to back lawn disassembled then hosed out.

Cheers - AL

[MitchellScott]

If I was looking to ferment under pressure I'd definitely be doing it with the Fermzilla. The collection bottle also doubles up to allow you to oxygen free dry hop without removing any pressure and therefore without any of that horrible mess.

[iBooz2]

By accident I recreated the issue of a Krausen blow up today.  All in the interest of science and this pressure fermenting thread of course, well that’s my story anyway.

Yesterday afternoon threw a new batch of Summer Ale into the fermzilla and used about 200ml of my freshly harvested Windsor yeast as per my previous post. By about 11pm there was still no sign of any activity but decided to leave it at 18 C and check it in the morning.

This morning when I checked some 17 hours later, still very little Krausen visible so first thoughts were oh no, yeast did not work!  Spunding valve gauge appeared to confirm this as showed 0 psi.  A closer look and the gauge was not resting on the 0 post it had gone right around and was hard up against the other side of the post so who knows what the psi was but must have been just less than the PRV which is 35 psi.

Quickly wound spunding valve back to release the pressure and in doing so caused a massive stir up of the wort.  When I say quickly it was just less than 1 minute but was enough for a massive Krausen to try and climb up into the gauge line.  Had to disconnect it until the honeycomb of Krausen had subsided.  This proves that any blow up is mainly due to quick pressure changes not the dry hops.

Note to self: Pre-set the spunding valve pressure and test/confirm before attaching to a new brew.

When I dry hop under pressure the release is done much more slowly say ½ turn of spunding valve every few minutes (whilst doing other things) and eventually get it down to 0 psi before open top gas port to sneak hops in.

@MitchellScott My first effort to dry hop was using the collection bottle as per you tube demos but I had fitted a small piece of hose on the inside slightly coiled.  Idea was to make the CO2 swirl around the hops and hopefully force all the Oxygen out the other side loosened cap but after trying this the once thought it seemed wasteful of CO2 and still not sure if all oxygen was purged plus I had to drag my gas bottle from one side of brew shed to the other.  Found it better to leave the bottom butterfly valve open from day one so the yeast could start dropping in the collection bottle immediately.  Note that I open the butterfly once yeast is pitched and lid sealed so as to create lots of bubbles turbulence up through the wort. 

It was less work and easier for me to simply drop the hops down though the opened gas port.

Cheers - AL

[MitchellScott]

18 minutes ago, iBooz2 said:

My first effort to dry hop was using the collection bottle as per you tube demos but I had fitted a small piece of hose on the inside slightly coiled.  Idea was to make the CO2 swirl around the hops and hopefully force all the Oxygen out the other side loosened cap but after trying this the once thought it seemed wasteful of CO2 and still not sure if all oxygen was purged plus I had to drag my gas bottle from one side of brew shed to the other.  Found it better to leave the bottom butterfly valve open from day one so the yeast could start dropping in the collection bottle immediately.  Note that I open the butterfly once yeast is pitched and lid sealed so as to create lots of bubbles turbulence up through the wort.

Correct that pressure change will cause it to rise, but adding the hops also increases this as you are adding nucleation points that causes C02 to come out of solution as soon as the hops go in. So its a double whammy.

One thing you could try if you like is running a gas line from the top of the fermenter straight to the collection jar and use the C02 the yeast has produced to purge the 02 out. I personally would prefer to use the bottle as you don't need much C02 to purge out a little container like the collection jar. But if you don't like wasting the gas then you can always do that

[iBooz2]

17 minutes ago, MitchellScott said:

Correct that pressure change will cause it to rise, but adding the hops also increases this as you are adding nucleation points that causes C02 to come out of solution as soon as the hops go in. So its a double whammy.

One thing you could try if you like is running a gas line from the top of the fermenter straight to the collection jar and use the C02 the yeast has produced to purge the 02 out. I personally would prefer to use the bottle as you don't need much C02 to purge out a little container like the collection jar. But if you don't like wasting the gas then you can always do that

Yes you are right there too.  I am still playing around with things to get my technique down pat re time efficiency etc.  Yes, I made up a special gas hose just for the purpose of purging the collection jar from FV CO2 back when I first got the Fermzilla but as I did not know how long it would take to purge most pf the oxygen just tried the bottle method.  One thing I was conscious of was overkill and too much purging and then maybe loosing some of the aroma from the dry hops, dunno.

I will give this a crack next brew as it will not hurt the butterfly being closed for the first 3 days re yeast drop anyhow I would not think.

Once I can get into a routine that works well and saves me time then will stick to that.  In the meantime its play around a bit and kick ideas around.

Cheers - AL

 

[Marty_G]

4 hours ago, MitchellScott said:

If I was looking to ferment under pressure I'd definitely be doing it with the Fermzilla. The collection bottle also doubles up to allow you to oxygen free dry hop without removing any pressure and therefore without any of that horrible mess.

I agree. Only thing that goes against them is they are such big buggers and will nearly fill my ferment fridge which is an upside down Westinghouse.  Also I think for what you get they are reasonably priced. 

[ChristinaS1]

On 3/12/2020 at 7:16 AM, Titan said:

Hope it a free article. https://byo.com/article/pressure-capturing-co2-fermentation/

It is not a free article. Any tips in it that you could summarize?

 

[Titan]

I will try and pick out some information from it.