[euge]

You should really weigh the sugar not measure it in "cups". I routinely use 3oz sugar for 5 gallons in a keg. If I were to bottle then it would be 4oz for the same 5 gallons.

[Joe Sr.]

Since I'm no longer bottling, it's sort of irrelevant...  At least to me.

[Jimmy K]

Also, if you were going to prime the keg with sugar - you use less due to the difference in headspace in the keg vs bottles. Usually 1/3 cup is about all that's needed to carbonate it.

Huh??  Unless you are knocking out lots of CO2 during the bottling process, it should take exactly the same amount of sugar to carb a keg as bottles.  It takes the same number of molecules of CO2 to get beer to a given volume of CO2 disolved.  Now, temperature during fermentation and bottling make a difference.  A lager should take much less sugar than an ale, due to the larger amount of fermentation-derived CO2 in the beer at a colder temperature. 

The head space might make a teeny tiny difference, but it shouldn't make much.

I always read that and assumed it was differences in headspace, but not that I calculated it there probably isn't much of a difference. I have read to use less sugar to carbonate kegs than bottles though. Hmm.

[oscarvan]

Like somebody said........ sugar is for boosting the octane. CO2 bottles are for carbonating. 

[davidgzach]

I've been a little dormant on the forum lately and just came back to this.  I decided to just stock my fridge with kegs and force-carb the one that is next in line for consumption.

I thought the reason to not use as much corn sugar in the mini kegs was because they could not take the pressure.  I would think the same amount in regular kegs would be appropriate.

Dave

[Joe Sr.]

I've rigged up a system to force carbonate mini-kegs and they take 40 lbs of pressure with no problem, so I don't think their ability to withstand the pressure is the issue.

On the one or two kegs that popped out into pointy kegs when primed with sugar, the beer was wildly over-carbonated.  Wildly.  It's the once instance where I came close to injury in home brewing.

I've heard the same advice to "under prime" corny kegs, so I have to think there are other reasons.  But I don't know what those reasons might be.

It's easy enough for someone who wants to prime their kegs to do a side by side experiment.

[Slowbrew]

Many years ago I witnessed what happens to fully carbed mini-keg when you add in a bit of shaking due to a 4 hour road trip.  Let's just say, we didn't ever use that keg again.  It held but it didn't sit flat anymore.   

Paul

[euge]

I've rigged up a system to force carbonate mini-kegs and they take 40 lbs of pressure with no problem, so I don't think their ability to withstand the pressure is the issue.

On the one or two kegs that popped out into pointy kegs when primed with sugar, the beer was wildly over-carbonated.  Wildly.  It's the once instance where I came close to injury in home brewing.

I've heard the same advice to "under prime" corny kegs, so I have to think there are other reasons.  But I don't know what those reasons might be.

It's easy enough for someone who wants to prime their kegs to do a side by side experiment.

Sounds like those kegs were infected. Don't cornies say not to exceed 150 psi? Basically they are steel bottles.

[tschmidlin]

I've rigged up a system to force carbonate mini-kegs and they take 40 lbs of pressure with no problem, so I don't think their ability to withstand the pressure is the issue.

On the one or two kegs that popped out into pointy kegs when primed with sugar, the beer was wildly over-carbonated.  Wildly.  It's the once instance where I came close to injury in home brewing.

I've heard the same advice to "under prime" corny kegs, so I have to think there are other reasons.  But I don't know what those reasons might be.

It's easy enough for someone who wants to prime their kegs to do a side by side experiment.

Sounds like those kegs were infected. Don't cornies say not to exceed 150 psi? Basically they are steel bottles.

The one i just checked said 130 PSI.  It may vary by manufacturer, but yeah, it's something really high.  I don't know about the mini-kegs though, I've never used them.

[denny]

The one i just checked said 130 PSI.  It may vary by manufacturer, but yeah, it's something really high.  I don't know about the mini-kegs though, I've never used them.

I think 130-135 is pretty standard.

[Joe Sr.]

Sounds like those kegs were infected. Don't cornies say not to exceed 150 psi? Basically they are steel bottles.

Not cornies.  Mini-kegs.  They are MUCH thinner steel, as they are technically disposable.

I've also pinged one out injecting it with a small CO2 cartridge, so their ability to withstand pressure is substantially lower than a cornie.  The tap stayed in just fine and all that holds it is the barbed fitting, but the bottom popped out on the keg.