knowing is half the battle!

[bracconiere]

just like G.I. Joe

i just hooked up a keg that should have been perfectly carbed at 1.2oz's co2...but even after a couple hours, it was pouring half foam. i was thinking just needs more time to settle. then next day still foam, i go, but i carbed by weight? how could it be over carbed? that's impossible? then the spirit of the wise kegger @day_trippr filled my soul...probably the dip tube o-ring...yanked the keg out of the fridge, vented , i think the dip tube o-ring looked like the orginal from 30 years ago it was so old....replaced it, perfect pour..


which would lead me to ask @doug293cz so you know gases...after i vented my keg to take the dip tube out, it looked like about a gallon got served...7 12oz pours by memory. and when i purged the keg with 10psi, i was crying watching the scale go down ~2oz's...i know you have your excel spreadsheet, can it be possible to do it by weight? one nerd to another?

 

[doug293cz]

just like G.I. Joe

i just hooked up a keg that should have been perfectly carbed at 1.2oz's co2...but even after a couple hours, it was pouring half foam. i was thinking just needs more time to settle. then next day still foam, i go, but i carbed by weight? how could it be over carbed? that's impossible? then the spirit of the wise kegger @day_trippr filled my soul...probably the dip tube o-ring...yanked the keg out of the fridge, vented , i think the dip tube o-ring looked like the orginal from 30 years ago it was so old....replaced it, perfect pour..


which would lead me to ask @doug293cz so you know gases...after i vented my keg to take the dip tube out, it looked like about a gallon got served...7 12oz pours by memory. and when i purged the keg with 10psi, i was crying watching the scale go down ~2oz's...i know you have your excel spreadsheet, can it be possible to do it by weight? one nerd to another?

When head space purging using gas exchange, the only tool you have is dilution. Each pressurize then vent cycle dilutes the O2 concentration by a fixed percentage of the remaining O2, depending on pressure. At 1X atm pressurize (~15 psig) you cut the remaining O2 by 1/2 each cycle. At 2X atm pressure (~30 psi) you cut the remaining O2 by 2/3 each cycle. You gotta do the cycles, so I don't see a way of doing it by weight.

There is no practical way to model (and thus predict) the concentration reducing effects of continuous flow purging, as the gas flow pattern inside the headspace is complex and unknown.

Brew on

 

[bracconiere]

I don't see a way of doing it by weight.

well i was thinking if i know how much weight of co2 i 'used'...i'd be able to tell how much is going in to fill the space....like if 1.28oz's is 5 gallons of co2, then if i filled 1 gallon at 10psi.....oh, hell...this is drunken rambling, and the keg will be empty in a couple days anyway...

i just wish i knew if i really needed to blow 2 oz's on purging it.....i was thinking, if i presurize it at 10 psi...hold on what air made of....21% oxygen, if i displaced 1 gallon of it with 2 oz's of co2...

 

[jddevinn]

In this case you can kinda think of the keg as a growler 1/3 full of beer. You fill it the rest of the way with water, shake it up so that it is evenly mixed then pour out so that only 1/3 of the growler has liquid in it. Fill it back up, stir, pour out to 1/3. Keep repeating. Eventually you can say that the growler is full of just water.

Then do the same thing with a 5 gal or a full keg. The number of CYCLES to get to the same dilution don't change, but the amount of water used does. This is why Doug's dilution graph does not rely on system volume, but is applicable to any container.

This is very simplified explanation.