No chill in corny keg

[Florian]

Yep, I realised that too, multiple times, even.

I did my little 'wort eats Co2' experiment and will post results a bit later tonight.

 

[manticle]

I will be fermenting in mine once my starter gets going. Put the gas on 50 kpa for a few hours on Saturday, turned it off, no tap etc on the beer out and it's maintained the 50. Presumably it would only start absorbing into the solution at much colder temperatures and if there was zero headspace in the keg. I am not super savvy with gas as I've mentioned but I am presuming that if there is headspace the gas will always come out of solution to equilibrate? Thus no chance of the poppets sucking anything in as they cool if you have gas in there.

Brew was no chilled on Saturday, has stayed at the same pressure the whole time.

 

[Florian]

I have once seen something that I found 'weird' which makes me a bit cautious with wort and Co2:
I had a 25L no chill cube, but only about 18L of wort, so the difference was too much to just squeeze the sides to push all the air out. I decided to just fill the cube and completely displace the head space with Co2, then pulled the lid tight.

The next morning all of the Co2 had been absorbed by the wort, there was literally no head space at all left in the wort and the cube was just a shrunken weird looking thing. I expected the walls to be pulled in a little by the cooling wort, with the volume of head space remaining the same, but instead the head space had disappeared completely.

Anyway, that's one of the reasons I wouldn't put the pressure on the reg too high, as it seems like the wort could 'eat' more Co2 than you would like too.

OK, so following up on that I filled 4 sprite bottles (acting as no chill cubes), two with water that had finished boiling one minute ago, and two with wort, again one minute after flame out.
The wort actually consisted of 2.5l of water and 220g of brown sugar, boiled for about 20 minutes with half a handful of Amarillo thrown in at the start of boil.

I filled all bottles with about 780ml of liquid, one wort and one water bottle I just closed the lid very tightly immediately (water+Air and Wort+Air), on the other two bottles I flushed the headspace for about 10 seconds each with Co2 at 80 kPa (Water+Co2 and Wort+Co2) and then closed the lid.

This is what the bottles looked like straight after filling (click on pic to supersize):




And this is what they look like about 30 hours later:




As you can see the head space in the Co2 flushed bottles is significantly smaller than in the ones with air in the head space, meaning that some of that Co2 would have been absorbed by the wort or water. Even more so when you consider that the wort+Co2 one was filled a little less originally than the wort+air one. If I had filled both to the exact level the difference would be even more visible.

Take from that what you want, all I'm saying is that the wort does seem to absorb Co2 in the cooling process. If it's a matter of 'the more Co2 you give (higher pressure setting on reg) the more it will absorb' I don't know, that would involve another fairly simple experiment (two cornies with same amount of hot water or wort and two Co bottles attached to the gas in, one with low reg setting and one with high setting. Weigh Co2 bottle before and after the cornies have cooled to determine how much Co2 has been absorbed).

I might actually do that just out of curiosity unless someone smart comes along and tells us if and why this happens.

Sorry Manticle, i hope this isn't taking your thread too far off topic, was thinking of starting a new thread but thought it sort of belonged in here. Feel free to split if off though, or even better tell me and I'll do it and add a preface to it.

 

[manticle]

I think it's perfectly relevant here.

 

[manticle]

Be interested if the wort has any detectable fizz.

 

[Florian]

Good point, have chucked both Co2 samples in the fridge, will check later. Although i suspect that it might not be enough.
I'm more interested though if the dissolved Co2 might have any impact, good or bad, on fermentation. I know yeast obviously produces Co2 but this is not dissolved in the wort from the start.

 

[TheWiggman]

Awesome post Florian, if nothing else it serves to show that using CO2 will post a significant hazard if not managed correctly. That hazard being the destruction of perfectly usable kegs.

 

[manticle]

My kegs have held shape fine the two times I've done this. Kegs are very different to PET bottles though.

 

[Florian]

Awesome post Florian, if nothing else it serves to show that using CO2 will post a significant hazard if not managed correctly. That hazard being the destruction of perfectly usable kegs.

I guess if you only flush the headspace once and then disconnect the gas this could in theory happen (someone volunteer to host that experiment?), although so far it seemed the consensus between us few that it's best to keep the gas connected at some sort of pressure, or at the very least pressurise the keg to a certain level before disconnecting the gas.

As I said I'd be interested on the effects this might have to the wort, yeast and fermentation.

 

[pk.sax]

Well, considering how finicky saison yeast is, I'll keep an eye on the ferment (through the opaque keg) and report if I can tell if the dissolved co2 is doing any harm to speed of ferment etc. The fridge is sitting at 22C all by itself, I had meant to tell the stalling of ferment by releasing the CO2 a few times a day and when it stops getting pressurised if know the ferment is stalled/done. Witherspoon the wort showers, I'm less keen to keep doing that. Would have to figure it out somehow. Maybe hook up the gas and see the pressure in the gauge rise without turning on the reg. won't work though because of the nrv .... Need some other solution of telling is fermenting is done.

CO2 is basically C++++ and O-- O-- somewhat polar molecules. That is why it dissolves in water better than just air, even at lower pressures it'd give you a fizz while nitrogen etc have to be dissolved at far higher pressures due to the absence of polar charges. Ionic substances have best solubility, followed by polar charge carrying covalent molecules.

 

[Florian]

That sort of seems like a sensible explanation, even though I admit that I don't understand it 100%. But it sounds like there would be a limit to solubility, so not a case of the more you gibe etc.?

As for telling when ferment is finished, I just attach a gas disconnect to the gas in post and hold a longish plastic container (just use a bucket or whatever you have on hand) right in front of it to catch the spray, let it settle and transfer to hydrometer tube.

Mine's still at 1.032 after 12 days, but it started at 1.082 so I give it a bit more time.

To be honest, I'm not 100% sure if I will pursue the cornie fermenting thing or not, but definitely will be no chilling in kegs from now on. If I acquire a ss fermenter I might just no chill in that if doing a single batch, but will no chill in cornies if wanting to store the wort for longer because I'm brewing multiple batches on a weekend, which will be the norm from now on.

 

[pk.sax]

Yeah, I've never been fully sold on the no-chill for hoppy beers though. For the rate of effort and changing process involved I tend to only do it for the wheat beers and like. The thing I hated about cubes was storage space and the stink they build from long disuse. Corny, no wukkin furries. Nappi-San + kettle water + lid on and shake shake sit and release and wash and starsan, job done every time on the mankiest keg unless there's congealed syrup (some of my first gumtree kegs had that issue). Cubes, well, if I can't see the spot how do I know it's got it + plastic harbouring bacteria...

 

[manticle]

Well a follow up on the gas thing. Didn't drop from 50 at any point since Saturday night.

Pulled the release valve tonight then shook the crap out of the keg to oxygenate as I would normally do with a cube. I plan on getting an O2 tank but shaking will have to do for now. Pulled the release valve again and would presume if any significant CO2 had gone into solution, that some would come out (and wort with it - likely in my face).

Nothing. Just like a cube only skinny and stainless. Added in my active starter, turned the release valve so it's pulled out - will see how it goes. Too much leakage and I'll sort a blow-off tube but I'm hoping I won't have to.

 

[Florian]

The thing is though that there wouldn't be much oxygen in the keg to oxygenate your wort, as you had flushed the head space with Co2 and also applied Co2 at pressure (that's what you did, right?). In that case you can shake it around as much as you like, but all you do is shaking the Co2 around.

Dependant on the yeast you're using and your desired outcome that could be good or bad. If you're concerned you could always open the lid and 'blow' some air in there and then repeat the shaking.

 

[Florian]

Also, instead of opening the release valve you could just attach a gas disconnect to the gas in post. That way, if your yeast rises too much, it just drips down the side of the keg, rather than all over the top. You could go all fancy and attach a tube to the disconnect and put it in a bucket with clean water, that way you're basically top cropping and have the yeast contained under water.

I know that's not what you want to do right now but it might give others some ideas.

I've completely nutted out my perfect process today, will post pics once I have all the gear together, which should be in about two weeks.

 

[manticle]

The thing is though that there wouldn't be much oxygen in the keg to oxygenate your wort, as you had flushed the head space with Co2 and also applied Co2 at pressure (that's what you did, right?). In that case you can shake it around as much as you like, but all you do is shaking the Co2 around.Dependant on the yeast you're using and your desired outcome that could be good or bad. If you're concerned you could always open the lid and 'blow' some air in there and then repeat the shaking.

released the co2 first, shook, removed lid, added yeast, returned lid, shook again. As I do with my cubes- I will be shaking intermittently till visible fermentation begins.
Not ideal but will have to do till I get O2 tank.

 

[pk.sax]

I like the top cropping idea. I've basically been releasing the pressure twice daily until the krausen starts wanting to come out. Then I stop - figuring I've dropped the pressure enough to let the subdued krausen rise to the top. Not like there was too much headspace anyway.

Btw, I cheated with the aeration. Wort was a bit over gravity so I topped with cold water in a spray from the hose. That should've introduced some oxygen. Temperature didn't drop much and I lidded and closed and applied co2 pressure. And pitched within 24 hours, with a starter. Not ideal but didn't pick up any infection, smell from the prv is very clean.

I mean, if pitching a starter large enough, is there really any need at all to oxygenate? Won't pitching to carbonated wort basically force the yeast to not grow and go anaerobic straight away?

 

[djar007]

If only corny kegs had conical bottoms.http://www.blichmannengineering.com/new-innovations-coming-soon

 

[manticle]

I know I'm tempting fate but there is a distinct krausen on the beer but nothing coming through the pressure valve as yet. I've just lifted it and turned it so it can't close. Maybe a litre or so headspace in the keg. No leakage so far.

If it stays like this, it's a very simple process.

 

[pk.sax]

Well, what's the chances of a speck of dust floating in through that bottleneck with a legion of screaming bugs on it's back!

You be fine

 

[manticle]

I could put a piece of glad wrap over it but I'm pretty confident in my mini-open fermentation, at least while it's active.

 

[manticle]

Got me paranoid so I put the release valve back in and just partially unscrewed it so it replicates what I do with my cubes. CO2 release with no dust able to fall in.

 

[pk.sax]

Bahaha. Really got you that dinnit.

I meant, it snakes down that hole with the spring and all that, hardly an infection risk...

I've put the belt on the fermenter today, the pressure was still building up but the temp was dropping. I'd be stoked if I can stop it from stalling this time.

 

[manticle]

Main thing is that krausen leakage seems so far to be non-existent.

Yes you did get me. Bastard.

 

[Florian]

I guess that's to do with the fact that you had the keg unpressurised from the beginning. Once you close it off and build up pressure it get's messy when you suddenly release the pressure.

Think coke bottle, take it out of the fridge, let it warm and then quickly open the lid = mess, take out of fridge, open lid, then let it warm + no mess, just because the Co2 is released as soon as it's coming out of solution, versus being ready to come out of solution (because coke warm), but pressure released (= lid opened) only once all Co2 is ready to come out.

 

[manticle]

I can imagine it would be totally messy but why would you close it off for fermentation? Either controlled (spunding) or just give the CO2 somewhere to go. It's no different to any other FV in that regard.

Or does the spunding hold until it's too much then release? In which case I'll stick with the slightly loose PRV.

 

[Florian]

With closing off I meant spunding, which is basically closing until a certain pressure is reached.

And yes, with spunding pressure builds up until it reaches or just overshoots a set threshold, then releases. But those commonly available spunding valves are unfortunately far from a precision instrument, it's a bit hit and miss and heaps of trial and error.

I'd love for someone to develop a digital one, keep pressure at exact 184 kPa or the like. I'm sure they exist, but would be unaffordable for the regular home brewer I'm sure.

 

[manticle]

If simply opening the PRV is enough, couldn't you do that and just attach the spunding valve for when the craziness has wound down (to achieve the natural carbonation)?

Or will the change in pressure release be enough to alter the beer significantly?

 

[Florian]

Yes, could do that, would work well. Used to do something similar with mostly wheat beers:

once gravity was somewhere 1.025ish I used to transfer from primary to keg and attach spunding valve. With some fancy calculations that would probably go totally over my head you could even calculate at what exact gravity you'd need to transfer to achieve x amount of carbonation.

one of the reasons I kept the pressure on this time though was to find out a bit about this whole pressure ferment and esthers thing.

 

[pk.sax]

Transferred the saison today. Few things.

Pressure seems to have made the saison go turbo in 2 weeks. Less than 2 weeks actually. Taste is dry, cannot detect any sweetness but the depth is there.

Most friggin annoying transfer ever. Wrt yeast, i.e. Unless you have the pressures etc set up perfectly for a fully closed transfer it's gonna be messy. I think on balance it is cheaper to spend a little gas and carbonate uncarbed beer than loose beer in wort showers and foam escaping the keg.

I hate not being able to see the level of beer in the vessels. I can feel the cold line descending and ascending but it is difficult to see when you got the yeast. I didn't get all the yeast out in the first hit before starting the transfer, the yeast was soft and fluffy.

Need to remember to take the gas off the keg transferring to and pressurise the fermenting keg before connecting them up or the gas shoots through the yeast and makes it all rise....

Don't think it was worth the bother on balance, I'm happy enough to wait longer for a ferment to finish at lower temps than deal with the mess.

Cleaning the keg post ferment however was a breeze compared to the carboy.