[jjflash]

My local gas distributor where I get my CO2 now has this 75/25% nitrogen/carbon dioxide mix.
I have always used just CO2 for racking and carbonating kegs.
He says many local guys use this 75/25 mix for their dark beers, but CO2 for their light beers.
He didn't know why, he was just passing on the information - this is primarily a welding gas shop.

I am tempted to try this when my next bottle runs dry.
The questions:
1) Use this mix because its gives a nice, small bubble, persistent head?
2) Why only on dark beers and not also with light color beer?
3) Can I pressurize my kegs with this mix, or use it only for beer delivery via the kegerator?
4) Can I use this gas to fill crown cap beer bottles from the keg with no ill effects?
5) If I fill bottles with this gas does it also improve the bottle beer head retention?
6) Lastly, he says they can do custom N/CO2 mixes. Any thoughts on benifits of various ratio gas mix?

Thanks all......

[tschmidlin]

You use it to get a Guinness type pour.  You can use it on light or dark beers, it's your call.  Typically you pressurize about 4 times higher than you would with just CO2, because the N2 isn't very soluble.  It helps to have a stout faucet, I'm not sure what it would look like through a regular faucet.  I've used 75/25 and 70/30, both are fine.

[mxstar21]

I am about to add a beer gas tank to my keggerator for my stouts.  I have heard to carbonate with CO2, and serve with the beer gas to get the Guiness head. 

[weazletoe]

  Does Guiness mix take a special regulator, or will a CO2 regulator work?

[mxstar21]

  Does Guiness mix take a special regulator, or will a CO2 regulator work?

I think you have to use a nitrogen tank, and I believe the threads are different than a CO2 tank.  I have just started to look into this, so hopefully someone more knowledgeable will chime in.

[jeffy]

  Does Guiness mix take a special regulator, or will a CO2 regulator work?

I think you have to use a nitrogen tank, and I believe the threads are different than a CO2 tank.  I have just started to look into this, so hopefully someone more knowledgeable will chime in.

Yes, there is an adapter you'll need to go from the tank to the regulator, but I have no idea the thread size.

[tschmidlin]

It depends on your local gas place.  Mine sells the mix in either a nitro tank or a CO2 tank.  I just get the CO2 tank so I don't need an adapter or different gauges, but I get less gas that way (the nitro tanks are rated for higher pressure).

You can carb with CO2 and push with the blend, or you can carb with the blend (I've done it, it works).  But I just carb with CO2 and save the 3.1 for pouring.

[jjflash]

Typically you pressurize about 4 times higher than you would with just CO2, because the N2 isn't very soluble. 

I don't understand this statement.
I seem to have forgotten all the physics I once learned in college years ago.
So, now I run my kegerator CO2 at 11psi @ 38 degrees F
Does this mean I crank up the N/CO2 mix to 44psi to push the beer at the same volume rate?
Don't seem right.....
 

[tschmidlin]

It depends on the level of carbonation you want in the beer.  If you try to push with 11 psi of 75/25 mix, you've only got 2.75 psi of CO2 on the beer.  At 38F, that's about 1.7 volumes of CO2 in your beer.  If you are happy with that level of carbonation, no problem.  But what you have now, 11 psi at 38F, is about 2.5 volumes.

"the same volume rate" is not what I'm talking about.  If you pressurize 4 times higher, you need to make your line about 4 times longer too, or replace it with a narrower line, otherwise it will just shoot foam.  The system has to be balanced so that the pressure at the tap is abut 0 psi.  Most nitro beers are served between 30-40 psi.

So decide what temperature you want your beer and how much CO2 you want in it.  That will determine what psi you should set the regulator for.  This in turn determines how long your line must be (for a given diameter) in order to balance the system.  That will get you the pour you want.

Read through the draft beer quality manual, it has a lot of great information.
http://www.draughtquality.org/w/page/18182201/FrontPage

[jjflash]

Thanks tschmidlin.
Makes perfect sense to me the way you explained this.
 

[tschmidlin]

Let us know how it turns out.