Naturally Carbonating A Keg + Some general regulator questions

[Nizmoose]

Hi Guys so after 1 year of brewing I decided I just couldn't resist the urge to buy at least a small keg set-up. My justification/excuse was to have beer on tap at my girlfriends 21st. I have since purchased a small set-up from cheeky peak (and would highly reccommend dealing with them really helpful bunch). My set-up consists of a 9.5L keg, 400gm CO2 bottle, mini reg, one way check valve, picnic tap and barbed ball lock disconnects.

Now I should mention that perhaps out of character for a 22 year old uni student I dont drink a 6 pack a day and unless going out wouldn't actually get through a 6 pack a week and thus this setup is perfect for me as I can take it around to mates places and parties and the like. So before I get people saying to just force carb with a bigger tank, no, for a few reasons, I only have a tiny CO2 tank and no part of that bothers me as it allows me to keep a keg on in the spare fridge in the shed without having a massive setup which would not make the parents happy (yep still living at home, don't know how they haven't killed me yet theres fermenters and pots everywhere). The other reason I would like to naturally carbonate is I think its kind of cool to do it somewhat naturally and let the yeast do that one last bit of carbonating.

So with my life story out the way here's a few questions I have even after close to 10 hours of reading on kegs and setups. Heres what the basic process in my head of priming and serving a naturally conditioned keg is (with questions along the way) :

1. Siphon the beer into the cleaned and sanatised keg
2. Add priming sugar using a proper keg priming calculator not the same amount as I would 9L bottled
3. Hit with 30PSI of CO2 and purge the keg 2-3 times to ensure no O2 is left
4. Give the keg a 1 or 2 minute shot with CO2 to ensure the lid seals
5. Disconnect the gas and sit it as I would bottles for 2 weeks
6. Heres where the questions come, is there any way to calculate the approximate PSI inside the keg based on how many volumes of CO2 I've added with sugar. For example if I've added enough sugar to aim for 2.5 vols of CO2 can I use a forced carbonation chart in reverese to determine that 2.5vols should equal xPSI in the keg? I ask this beacause I would rather avoid purging the excess co2 before hooking up the tank with serving pressure because I hear you will lose volitile aroma compounds? Thus if it was possible to calculate the PSI in keg before serving I could either hook up 10psi of serving pressure and know that the beer wont go up the gas line (I know I have a check valve but still) or alternatively would know that I can simply serve off of the keg's residual pressure until the pour slows and I hook up the CO2 with serving pressure. Also should point out that yes I know guages can be purchased to check the keg pressure but I would rather not spend the cash at the moment and thus was hoping for a way to make a good estimate.

Lastly unrelated to the above method I'd like to know how to treat my regulator properly. My co2 tank has a tap and when not in use I have the tap closed, lets say my serving pressure is 10psi and thus the regulator is set at that, when turning off the gas and disconnecting it should I kill the gas tap first then wind out the regulator tap to zero before storing or should I wind the psi to zero on the regulator and then turn off the gas at the bottle? Also should this all be done with the gas disconnect DISCONNECTED from the keg? Im assuming setting the reg to 0 before disconnecting will shoot beer up the gas line?

Also will the diaphram on the reg not enjoy having the regualtor sit at say 10psi when not in use or doesnt care? I liken this scenario to a torque wrench where you're always supposed to store a torque wrench with the tightening nut loose as to not wear out the spring and throw out the calibration.

Sorry for such an essay of a post but its those last few little things that I haven't been able to find definitive info on yet and know people will know straight away from experience (of which I have none)

Thanks in advance

 

[Dave70]

Not sure if this is what you're getting at, but it's something I took an interest in a while back but have yet to do. My thinking was this method would infuse the beer with all that lovely late hop goodness that bubbles off with the co2. Perhaps.
Cant get much more 'natural' than carbing up your beer with the farts of the yeast who made it.

https://byo.com/grains/item/397-build-your-own-spunding-valve-to-carbonate-in-the-keg

 

[Grott]

Hi Nizmoose, I now use 9.5l kegs as well and have a fridge setup plus the ability to take a keg somewhere. I don't carb. naturally and can't help with calculations to work out vol. of co2 other than a gauge as Dave70 has shown. However after your keg is carbonated place in fridge to cool down to your serving temp. I would not connect the gas but test by pouring first to establish carb level in the keg. Note the first 50/100 ml will be sediment that has settle to the bottom of the keg, so drink/toss this before your test. If all good pour until you need to connect the gas at serving pressure.

When disconnecting the gas line I disconnect the line from the keg, turn off bottle. The serving pressure will still be in the line and thus a good check for slow leaks.

For your info. thanks to qldkev's co2 usage calculator, you should get 21.1 kegs for dispensing beer from your 400gm co2 bottle. ( not including purging of oxygen, extra carbonating and waste.

Cheers

 

[AntonW]

Hi Nizmoose,

You need far less sugar than you would for 9.5 litres bottled. The headspace:liquid ratio is far lower in a keg, so more of the CO2 will end up in solution. From my experience, about 1/3 of the amount is right.

Better, though, is to keg the beer when it's still got 5-10 points of gravity left to ferment. I've never been too precise on this, but you'll figure it out. The advantage of this is that you don't end up changing the flavour of the beer by fermenting additional simple sugars.

Given that you've only got a small CO2 bottle, I wouldn't worry about purging the keg. The yeasties will eat up any oxygen in there pretty quickly, and the act of filling the keg will purge most of the O2. You've said that you'll use a siphon. This is good because it'll prevent excessive wort aeration.

Setting the reg to 0 before disconnecting it is unlikely to cause problems because there's still pressure in the line (unless you purge the reg), and because the reg is connected to the gas disconnect, which sits above the liquid level. Just don't tip the keg over. But, accidents will happen (especially if you take it to parties) and you should consider a check valve for $10 from keg king.

Good luck, and drink more beer. You'll learn faster.

Cheers.

 

[AntonW]

re: leaving the reg at serving pressure.

I don't think it's like a torque wrench at all. Most people leave their regulators at serving pressure indefinitely to maintain carbonation. The diaphragms only have a limited life before they wear out, and I'm pretty sure that's related to the age of the regulator rather than the amount of use its had.

You won't be able to dispense a whole keg without adding more gas. If you can, the first three quarters of the keg will be pure foam. This is what happens if you use the same amount of priming sugar that you'd use for bottles. As you dispense the beer, the pressure in the headspace will drop.

My reccomendation would be to keg with a few points of gravity left, and then force carbonate a week or so later, but use a stop watch so that the process is somewhat repeatable. Honestly, priming the keg is more effort than what it'll save you in CO2, and it's nice to know that the flavour of the beer isn't going to change due to additional fermentation.

 

[Nizmoose]

Thanks heaps for the replies guys

Not sure if this is what you're getting at, but it's something I took an interest in a while back but have yet to do. My thinking was this method would infuse the beer with all that lovely late hop goodness that bubbles off with the co2. Perhaps.
Cant get much more 'natural' than carbing up your beer with the farts of the yeast who made it.

https://byo.com/grains/item/397-build-your-own-spunding-valve-to-carbonate-in-the-keg

Hi Dave I have read this article a few times before and will probably end up getting one although if someone does know what an approximate keg pressure is after priming for roughly 2.3-2.5 vols of CO2 and its not ridiculously high then I'll happily serve off the residual pressure until the pour slows the hook up co2 I'll probably get bored one day and build of of these valves though

Hi Nizmoose, I now use 9.5l kegs as well and have a fridge setup plus the ability to take a keg somewhere. I don't carb. naturally and can't help with calculations to work out vol. of co2 other than a gauge as Dave70 has shown. However after your keg is carbonated place in fridge to cool down to your serving temp. I would not connect the gas but test by pouring first to establish carb level in the keg. Note the first 50/100 ml will be sediment that has settle to the bottom of the keg, so drink/toss this before your test. If all good pour until you need to connect the gas at serving pressure.
When disconnecting the gas line I disconnect the line from the keg, turn off bottle. The serving pressure will still be in the line and thus a good check for slow leaks.
For your info. thanks to qldkev's co2 usage calculator, you should get 21.1 kegs for dispensing beer from your 400gm co2 bottle. ( not including purging of oxygen, extra carbonating and waste.
Cheers

Cheers Grott, didn't know I'd be able to get 21 kegs dispensed and funnily after many a search for a calculator I didnt know QLDkev had one! will definitely have a look, somehow I've managed to use 50g by dicking around with it and cleaning my keg, having a play etc but it's nice to know that I'll get a good few dispenses out of the tank I have!

Hi Nizmoose,

You need far less sugar than you would for 9.5 litres bottled. The headspace:liquid ratio is far lower in a keg, so more of the CO2 will end up in solution. From my experience, about 1/3 of the amount is right.

Better, though, is to keg the beer when it's still got 5-10 points of gravity left to ferment. I've never been too precise on this, but you'll figure it out. The advantage of this is that you don't end up changing the flavour of the beer by fermenting additional simple sugars.

Given that you've only got a small CO2 bottle, I wouldn't worry about purging the keg. The yeasties will eat up any oxygen in there pretty quickly, and the act of filling the keg will purge most of the O2. You've said that you'll use a siphon. This is good because it'll prevent excessive wort aeration.

Setting the reg to 0 before disconnecting it is unlikely to cause problems because there's still pressure in the line (unless you purge the reg), and because the reg is connected to the gas disconnect, which sits above the liquid level. Just don't tip the keg over. But, accidents will happen (especially if you take it to parties) and you should consider a check valve for $10 from keg king.

Good luck, and drink more beer. You'll learn faster.

Cheers.

Thanks for these pieces of advice, I do have a check valve so no worries there, I'm not the sort to risk a regulator for the sake of a 9 dollar check valve haha I just figured if I can keep the gas line beer free then good haha. The racking to the keg early in terms of gravity points I really like, cool new thing to try. What I'm sensing from these answers is theres nothing wrong with leaving the reg set to say 10psi when storing it disconnected from the keg?

 

[Nizmoose]

re: leaving the reg at serving pressure.

I don't think it's like a torque wrench at all. Most people leave their regulators at serving pressure indefinitely to maintain carbonation. The diaphragms only have a limited life before they wear out, and I'm pretty sure that's related to the age of the regulator rather than the amount of use its had.

You won't be able to dispense a whole keg without adding more gas. If you can, the first three quarters of the keg will be pure foam. This is what happens if you use the same amount of priming sugar that you'd use for bottles. As you dispense the beer, the pressure in the headspace will drop.

My reccomendation would be to keg with a few points of gravity left, and then force carbonate a week or so later, but use a stop watch so that the process is somewhat repeatable. Honestly, priming the keg is more effort than what it'll save you in CO2, and it's nice to know that the flavour of the beer isn't going to change due to additional fermentation.

Okay just saw this, that makes sense, in my head my process would be along the lines of priming with sugar to obtain desired carbonation and then for serving hook up the CO2, I'm not bothered at all by using the co2 to serve right from the get go and would never overprime for the sake of trying to score some serving pressure out of the carbonation process, my assumption is that if my system wants 10PSI to carbonate at 2.3vols at whatever temp I have in my fridge then using sugar to prime to 2.3 vols should bring the keg pressure pretty close to that 10psi allowing me to simply pour a beer to test then hook up the CO2 to serve? Also Re: Regulator good to know I wont be wearing it out having it constantly screwed in that just means i'll disconnect the whole line and turn off the gas at the bottle when not in use cheers.

 

[manticle]

Kegging the beer early is a good way to get residual acetaldehyde and/or vdk in the finished beer unless you carbonate by krausening with fresh yeast.

Priming a keg is easy - use no more than 50% of the equivalent bulk priming amount then dispense at serving pressure.
Most times, I turn my reg off and just give a quick burst when the flow slows but I don't enjoy super fizzy beer.

 

[Nizmoose]

Kegging the beer early is a good way to get residual acetaldehyde and/or vdk in the finished beer unless you carbonate by krausening with fresh yeast.

Priming a keg is easy - use no more than 50% of the equivalent bulk priming amount then dispense at serving pressure.
Most times, I turn my reg off and just give a quick burst when the flow slows but I don't enjoy super fizzy beer.

Thanks manticle, I sort of forgot about young beer and normally like to leave my beer in the fermenter for 3 weeks before bottling because I find as many others have that the last few bottles definitely taste the best. Don't want to remove that ageing step so will just prime as usual. Thanks for all the help guys, my first kegged batch is currently cold crashing and is going into the keg on Friday so hoping all goes well!