# Priming A Keg With Sugar



## Nick JD (26/1/11)

I've been dragging the web for an hour now trying to find out how much sugar to use to get a "normal" carbonation in a 19L keg.

Everywhere seems to say, "half" what you'd use for bottles. Some say 2g/L and some say 6g/L ... bottling is ~8g/L isn't it?

Say I wanted 2.5 volumes (decent carb level), how much sucrose should I use? 

And do I need to give the keg a few squirts of CO2 to seal the lid?

:icon_cheers:


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## Hatchy (26/1/11)

I've been thinking about doing this as well. I'd suggest using co2 to seal the lid & to get the o2 out.

As far as how much sugar to use I've got no idea. I'm looking forward to seeing what other blokes say though.


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## geoff_tewierik (26/1/11)

I have to ask why you're planning on priming the keg when you could just carb it with the CO2 you already have?

Priming the keg will lead to yeast being deposited in your glass when you pour a beer, due to the beer out drawing from the bottom of the keg, i.e. the middle of the dead yeast pile.


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## schooey (26/1/11)

Nick JD said:


> I've been dragging the web for an hour now trying to find out how much sugar to use to get a "normal" carbonation in a 19L keg.
> 
> Everywhere seems to say, "half" what you'd use for bottles. Some say 2g/L and some say 6g/L ... bottling is ~8g/L isn't it?
> 
> ...



There is not a bad calculator here that I have used with success. As for purging with CO2, that seems to be a matter of opinion. As far as most of the learned people I have spoken to about it are concerned, any excess oxygen in the keg will soon be consumed by the yeast and replaced with CO2... I have done both and noticed no difference


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## Nick JD (26/1/11)

geoff_tewierik said:


> I have to ask why you're planning on priming the keg when you could just carb it with the CO2 you already have?




I have to ask because it's for a portable keg with a keg charger for dispensation only. I'm aware that there will be yeast in it. I like yeast in some beers. Thank you for your input.


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## Nick JD (26/1/11)

schooey said:


> There is not a bad calculator here that I have used with success. As for purging with CO2, that seems to be a matter of opinion. As far as most of the learned people I have spoken to about it are concerned, any excess oxygen in the keg will soon be consumed by the yeast and replaced with CO2... I have done both and noticed no difference



That seems to be for bottles that calculator. I've read in a few places that kegs only need half the sugar for priming. Do you use that for keg priming?

I'm not concerned about oxygen in the keg (it'll be taken up by the yeast), but do I need a little bit of pressure to ensure the yeast-made CO2 doesn't leak out the lid before any pressure is built up?


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## roller997 (26/1/11)

Nick JD said:


> That seems to be for bottles that calculator. I've read in a few places that kegs only need half the sugar for priming. Do you use that for keg priming?
> 
> I'm not concerned about oxygen in the keg (it'll be taken up by the yeast), but do I need a little bit of pressure to ensure the yeast-made CO2 doesn't leak out the lid before any pressure is built up?




In the past, when I bulk primed in the fermenter for bottling & kegging I had identical ratios of DME in the keg which might explain the higher carbonation in the keg dispensed beers. Mind you, they were easily fixed as it is easy enough to release a bit of pressure after the first sample if it is too highly carbonated.
A also checked with my Beersmith software and the software suggests that you use about 50% of the corn sugar in a keg than you use in bottles. This would mean for a beer that finished at 20 degrees, you would need 62 grams of corn sugar in a 19l keg as opposed to 125 grams for bottling.
I also prefer natural carbonation in kegs as I believe the takeup of oxygen and the slow creation of CO2 produce a better result.
In terms of not wanting a glass of yeast in your brew - You can always shorten the pickup tube, however like you I also like yeast in some of my beers.

Regards

Roland


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## schooey (26/1/11)

Sorry....I fail to see the difference. The keg is just a bigger vessel, or bigger version of a bottle. Why would you only need half? When I bulk prime a batch, I often put half in bottles and half in a keg, never had a problem. Where I have had probles is bulk priming under attenuated beers, but that's not discriminative by bottle or keg either.

As for the kegs holding pressure, I don't have an issue there either. My lids pull up tight enough on the o-ring with the over centre latch to make a seal.


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## TBird (26/1/11)

Coopers recommend 4 grams per litre.


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## Phillbo (26/1/11)

I always sugar prime my kegs, 60g of sugar gives a low carbinated beer (how I like them), my beers are about six months old when I crack them, yeast in the first glass, clear as from then on. I also pressurize the keg to get a good seal after adding the sugar


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## Nick JD (27/1/11)

I think I'll try 75g. Thanks all.


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## barls (27/1/11)

i normally work out what it should be when bottling then half and use that amount in my kegs


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## Barry (27/1/11)

I usually bulk prime a batch because I always bottle at least a few even if kegging. Usually don't have enough fridge space to get the keg cold and carbonated so priming it allows it be carbonated while warm. Then I put it in the fridge when I want to tap it, let it get cold, release pressure if necessary and serve. Bit yeasty the first glass or two but fine after that. Only have three fridges, one bar fridge and a kegerator. Usually 3 serving kegs in the kegerator but the rest are normally full of fermenting beer at different temps.


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## Rotgut (27/1/11)

Whenever I do it I use 1/3 cup of dextrose with good results. Don't worry about yeast settlement, goes in the first 2 glasses.


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## MarkBastard (27/1/11)

Most of my keg lids seal without pressure.


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## bignath (27/1/11)

I'm glad Nick's asked this question because i have a few of those "commercial" 5L mini kegs i plan to use as camping beers and would love to know the answer..

I have also heard about only using half the amount of sugar that you would for a bottle, but can anyone explain why this would be the case??

And as a small deviation, i would assume by this logic that the closer your batch size gets from a keg to a bottle, the bigger the ratio of sugar to bulk prime? 

If you consider a bottle to be 100% sugar for carbing, a 19L keg 50%, what would a 5L keg need?

Cheers and sorry for the slight dragging from Nick's OP

Nath


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## pbrosnan (27/1/11)

I bulk prime in the fermenter. I usually bottle about 3 litres for samplers/competitions and keg the rest so as far as I'm concerned there's no distinction.


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## fraser_john (27/1/11)

90gm in a keg seems to get pretty darn close to perfect in my set-up, usually it is a little under-carb'd, but I would prefer that than over carb'd.


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## Hashie (27/1/11)

76 grams gets 2.4 volumes of CO2 in a 19 litre keg.


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## katzke (27/1/11)

schooey said:


> Sorry....I fail to see the difference. The keg is just a bigger vessel, or bigger version of a bottle. Why would you only need half? When I bulk prime a batch, I often put half in bottles and half in a keg, never had a problem. Where I have had probles is bulk priming under attenuated beers, but that's not discriminative by bottle or keg either.
> 
> As for the kegs holding pressure, I don't have an issue there either. My lids pull up tight enough on the o-ring with the over centre latch to make a seal.






Big Nath said:


> I have also heard about only using half the amount of sugar that you would for a bottle, but can anyone explain why this would be the case??
> 
> 
> Nath



Answer both at once.

Head space in percentage. I bet if you are a math whiz and calculate out the headspace, O2 consumed and replaced, and other factors you would find that bottles require more CO2.

As to why purge and seal the lid? Why not. Not all kegs are in great shape. The chance of flat beer is not worth it. There is more to sealing a keg then just the lid. If in doubt search posts on empty CO2 tanks.

For those asking why bulk prime a keg? I am sure there are many reasons. Just dont worry if you do not have to.


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## Nick JD (27/1/11)

I just kegged the batch with 80g - I was going for 75 but poured too much in the container on the scales - so 80g it is! It's a hoppy lager.

When I shook the keg up to dissolve the sugar it produced a bit of pressure and I did a leak test on the IN and OUT and the lid and gave it a fart and it's all good so far.

I'd also like to know the physics behind volumes of CO2 being the same, but different in kegs vs bottles.


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## loikar (23/6/11)

_"I'd also like to know the physics behind volumes of CO2 being the same, but different in kegs vs bottles."

_BIG! bump

Anyone?


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## Ross (23/6/11)

Nick JD said:


> That seems to be for bottles that calculator. I've read in a few places that kegs only need half the sugar for priming. Do you use that for keg priming?
> 
> I'm not concerned about oxygen in the keg (it'll be taken up by the yeast), but do I need a little bit of pressure to ensure the yeast-made CO2 doesn't leak out the lid before any pressure is built up?




you should be purging the keg of air - The priming sugar wont come close to consuming it. 

If you shook up your beer to dissolve the sugar, then you'll have oxidised your beer. Hopefully not to an extent that ruins the final beer.

Cheers Ross


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## barls (23/6/11)

im thinking it has something to do with me purging the headspace after i fill it. this leaves me part way there to the final pressure required


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## Nick JD (23/6/11)

Ross said:


> you should be purging the keg of air - The priming sugar wont come close to consuming it.
> 
> If you shook up your beer to dissolve the sugar, then you'll have oxidised your beer. Hopefully not to an extent that ruins the final beer.
> 
> Cheers Ross



Well, that keg was gone five months ago, but thanks for the advice! The keg was so full it was up to the gas post - so no worries there - less headspace than a bottle by far. 

Since then, I've given up on natural carbing kegs. Not worth the savings in CO2 - I get 2.3 kg for $16.50.


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## Dickster86 (23/8/16)

I use carbonation drops and find that about 15 drops in a 9.5L keg and that seems to work great. Shake the hell out of it (just like you would a bottle) and no need to add any extra gas. Works a charm. The carbonation drops recommend 1 per 330ml stubbie, so its about half of the recommendation (9.5L / .33L = 28.78). Keen to try priming with dme or just pure dextrose in the future though


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## Lyrebird_Cycles (23/8/16)

Since this has been resurrected:



katzke said:


> Head space in percentage. I bet if you are a math whiz and calculate out the headspace, O2 consumed and replaced, and other factors you would find that bottles require more CO2.


This is NOT the answer. Headspace correction is included in the calculator I wrote and it works the opposite way: the more headspace you have the more priming (per litre beer) is required. This is logically the case, the beer volume needs to generate enough CO2 to bring the headspace into equilibrium in addition to the amount required to achieve carbonation.

I do not know what the answer is.

I suspect it is something as simple as a combination of desired CO2 level being lower in cask conditioned beers and needing to undercarbonate to account for the CO2 absorbed when it is pressurised for serving. Since I don't drink enough to bother with kegs, I can't answer from experience.


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## RelaxedBrewer (23/8/16)

Dickster86 said:


> I use carbonation drops and find that about 15 drops in a 9.5L keg and that seems to work great. Shake the hell out of it (just like you would a bottle) and no need to add any extra gas. Works a charm. The carbonation drops recommend 1 per 330ml stubbie, so its about half of the recommendation (9.5L / .33L = 28.78). Keen to try priming with dme or just pure dextrose in the future though


Just weigh out 15 carb drops and that is how much sugar you need to add.

Are carb drops dextrose or sucrose?


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## Lyrebird_Cycles (23/8/16)

The Coopers ones are apparently a mixture of about 3/4 sucrose and 1/4 glucose (=dextrose). I'm assuming this is because it's much harder to get a pale hard candy from glucose (tends to make soft candy).


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## Rocker1986 (23/8/16)

Dickster86 said:


> I use carbonation drops and find that about 15 drops in a 9.5L keg and that seems to work great. Shake the hell out of it (just like you would a bottle) and no need to add any extra gas. Works a charm. The carbonation drops recommend 1 per 330ml stubbie, so its about half of the recommendation (9.5L / .33L = 28.78). Keen to try priming with dme or just pure dextrose in the future though


Are you trying to oxidise it? There is no need to shake either bottles or kegs; it does nothing to dissolve the drops and the yeast will find and ferment the priming sugar regardless.


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## Aus_Rider_22 (23/2/17)

Sorry to rebump this thread.

I have come to a dilemma. I keg most of my beers and was planning to keg my BIPA this afternoon. But last night my co2 blew and I won't be able to refill until next weekend (co2 refill is available 1hr away but due to weekend opening times I can't make it this weekend.)

I have 18L of this brew and was going to add dextrose and leave it be. I have only ever naturally carbonated a keg once before and I had my co2 to displace the headspace after filling. 

After reading through this thread, I am worried that 18L of beer will leave too much headspace and oxidise my beer even after secondary fermentation. Thanks for any help.


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## mofox1 (23/2/17)

Aus_Rider_22 said:


> Sorry to rebump this thread.
> 
> I have come to a dilemma. I keg most of my beers and was planning to keg my BIPA this afternoon. But last night my co2 blew and I won't be able to refill until next weekend (co2 refill is available 1hr away but due to weekend opening times I can't make it this weekend.)
> 
> ...


Have you got any other pressurised kegs? If so you can rig up a gas to gas line and purge your newly kegged beer using the pressurised kegs.

Then again, this would leave you with no kegged beer to drink, which IMO is bad. I'd leave it in the fridge and delay the kegging until I have CO2 to spare... an extended cold crash won't hurt.


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## Aus_Rider_22 (23/2/17)

mofox1 said:


> Have you got any other pressurised kegs? If so you can rig up a gas to gas line and purge your newly kegged beer using the pressurised kegs.
> 
> Then again, this would leave you with no kegged beer to drink, which IMO is bad. I'd leave it in the fridge and delay the kegging until I have CO2 to spare... an extended cold crash won't hurt.


 I have 2 kegs of lager in my kegerator at the moment. They have been lagering for 3 weeks now and are bright as ever, so I don't want to move/disturb them. 

The more I think about, I will just keep it simple and bottle this batch. I have plenty of clean bottles and carb drops so I will do that and bring bottle stocks up. No point risking oxidisation on this batch which is tasting suburb just from the gravity taste! 

Thanks for your help mofox1, I appreciate it.


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