Purging Kegs with nitrogen

[Tony121]

Hi, not sure if this is the right spot to put this question and apologise in advance if it is a stupid question but....

Does anyone see an issue with purging kegs with nitrogen to remove oxygen when kegging as opposed to CO2?

I know nitrogen is used for dispensing and also with a nitro/CO2 mix but not sure if there are any issues associated. I have tried to search but can't find any specific answers.

Reason I ask is that I have access to nitrogen and would like to save my CO2 for carbonation.

 

[MHB]

If you aren't paying for the N2 - no problem. Mind you CO2 is pretty cheap, if you had to buy a N2 regulator or to pay rent on the bottle I doubt you would save anything.
Mark

 

[Tony121]

Thanks Mark, much appreciated.

No cost involved for nitrogen so will be in front.

 

[Jack of all biers]

You can also use nitrogen to carb..... Well nitrogenate... If it's costing you nothing that is. When I worked in pubs in Europe, Guinness recommended/preferred that their product was served using nitrogen. From memory it was to do with keeping the head of the beer whiter and flavour consistency. Our owners used CO2 as it was cheaper and the average punter couldn't tell the difference

 

[welly2]

Can you use nitrogen in standard micromatic regulators? At some point I'd be interested in carbing a stout with nitrogen.

 

[quadbox]

You're not actually saving a whole lot of co2 though btw. Not unless you're running a hot-keg system anyway. 2.5 volumes of co2 carbonation for a 19L keg's around 100g of co2 (just over 2 mol). A litre of headspace purged at 80kPa at 4C is about 1.2 grams of co2. So your grand total of savings for stuffing around with switching gas lines etc is all of 1%

EDIT - And if what you were saying is you also want to serve it with straight nitrogen, the answer is no, that doesnt work. You need to maintain the partial pressure of CO2 at carbonation partial pressures, or all your co2 is going to come out of solution even if you're running your nitrogen at 100kPa. Its the partial pressure of co2 that's important, not the overall pressure of every gas combined

 

[MHB]

Can you use nitrogen in standard micromatic regulators? At some point I'd be interested in carbing a stout with nitrogen.

Well probably not, if its a "standard " CO2 reg, the bottle connections are different, CO2 is a flat face and N2 is a round well similar to what is on an LPG bottle (similar not necessarily the same and different thread RH rather than left hand).
Regulators are also designed to work over different ranges, N2 is bottled at around 2MPa, CO2 is stored at around 0.5MPa, so unless you know it's safe to use at 4 times its rated performance I would be just a bit cautious.
Mark

 

[danestead]

You can also use nitrogen to carb..... Well nitrogenate... If it's costing you nothing that is. When I worked in pubs in Europe, Guinness recommended/preferred that their product was served using nitrogen. From memory it was to do with keeping the head of the beer whiter and flavour consistency. Our owners used CO2 as it was cheaper and the average punter couldn't tell the difference

You've been mislead. A pub situation with long lines is different to a home brew system with short lines. You will get vastly different products if you 'carb' with nitrogen instead of co2.

Edit: Beaten above.

 

[quadbox]

I'd also point out that even in a long-line draught system, and oh boy are long-line draught systems a different kettle of fish to home systems, nitrogen mix systems are on the way out in a big way, and have been for over a decade, because they're a royal pain in the arse. Beer pump systems are cheaper to run, massively easier to keep balanced, especially if you've got multiple serving points and different products with different keg carbonation... and the initial outlay is comparable.

As someone who's managed bars with just about every sort of system over the years I wouldnt install a nitrogen system in a pink fit unless there was a special need for it (ie, guinness, or another nitro-tap), and even then I'd probably just isolate that particular line, set it up with a beer pump, and run it on premix. You think keeping a home tap balanced is a pain in the arse, oh boy.

 

[Tony121]

You can also use nitrogen to carb..... Well nitrogenate... If it's costing you nothing that is. When I worked in pubs in Europe, Guinness recommended/preferred that their product was served using nitrogen. From memory it was to do with keeping the head of the beer whiter and flavour consistency. Our owners used CO2 as it was cheaper and the average punter couldn't tell the difference

Not sure how true it is but I have heard that nitrogen gives smaller bubbles which gives a creamier effect. But is this just from serving with nitro or is it "nitrogenated" to that point?

You're not actually saving a whole lot of co2 though btw. Not unless you're running a hot-keg system anyway. 2.5 volumes of co2 carbonation for a 19L keg's around 100g of co2 (just over 2 mol). A litre of headspace purged at 80kPa at 4C is about 1.2 grams of co2. So your grand total of savings for stuffing around with switching gas lines etc is all of 1%

EDIT - And if what you were saying is you also want to serve it with straight nitrogen, the answer is no, that doesnt work. You need to maintain the partial pressure of CO2 at carbonation partial pressures, or all your co2 is going to come out of solution even if you're running your nitrogen at 100kPa. Its the partial pressure of co2 that's important, not the overall pressure of every gas combined

Fair point would not save much, however it is also a matter of convenience. My CO2 bottle sits in the fridge and is a pain in the arse lifting in and out to purge after kegging and also to have to change my reg setting each time. To be honest, it is not that bad but would rather not have to do it.

 

[MHB]

He's right, I set up a mixed gas tap system for my self. 70/30 N2/CO2 you need around 200kPa to get the right dissolved gas balance, takes about 2-3 weeks to absorb enough N2 to work like it should, you need a special regulator and a tap with a cream pour fitting. Right royal PITA.
Personally I think N2 guts the beer hiding a hell of a lot of the flavour.
Buy a lava lamp if you want something to watch and stay with CO2 for serving beer; or play around with cask conditioned ales.

The OP was about flushing O2 out of kegs with N2 rather than CO2, very different question to serving with Mixed Gas or N2.
Mark

 

[MastersBrewery]

The nitrogen in a nitro setup is there to provide presure without absorbtion. That is to say the nitrogen isn't absorbed into the beer as Co2 is the pressure is what makes the bubbles so tiny. I've always wondered if you ran a beer pump at higher pressure if you would get the same result as a nitro setup. End of the day nitrogen is for creating pressure without gasing the beer, wether that be to push long runs or create that special stout effect.

MB

 

[quadbox]

The nitrogen in a nitro setup is there to provide presure without absorbtion. That is to say the nitrogen isn't absorbed into the beer as Co2 is the pressure is what makes the bubbles so tiny. I've always wondered if you ran a beer pump at higher pressure if you would get the same result as a nitro setup. End of the day nitrogen is for creating pressure without gasing the beer, wether that be to push long runs or create that special stout effect.

MB

If you're interested in the physics of it, what tiny amount of n2 that's in solution comes out of solution really easily, and the reason you get the tiny bubbles is because that bit of nitrogen coming out of solution suddenly creates an enourmous number of tiny nucleation points, so you get co2 bubbles joining the nitrogen... Most of the actual gas in the tiny bubbles is still co2, it's just that the nitrogen coming out of solution (which it does at the drop of a hat unlike co2) as the beer's forced through your restrictor plate in the stout tap makes it way easier for the co2 to form bubbles, so they happen smaller.

That's my understanding of it anyway, I've not run a model of it.

 

[MHB]

Sort of close, N2 is far less soluble than CO2, but when you are preparing a cream pour beer you absolutely do want the N2 dissolved in the beer, as it is something like 1/9th (from memory) as soluble as CO2 you need a much higher pressure to get much into solution. You couldn't pour beer from the tap if the pressure was that high, therefore the restrictor plate, without it the beer would do a U-turn at the bottom of the glass and irrigate you, your ceiling, the carpet in the next room...
Yes it breaks out very quickly (makes lots of small bubbles/foam), the other factor that make it come out a lot faster is that it doesn't form a complex like CO2 in water forms carbonic acid in an equilibrium depending on how much is in solution. Quite a lot of the CO2 isn't able to come out of solution immediately as it is otherwise occupied. The Carbonic acid lowers the pH of the beer and that to has an effect on the flavour - flat beer yuck! Its also worth trying the same beer at different levels of carbonation, it really does matter.
Mark

 

[Jack of all biers]

Yeah what MHB said above fits with what the Guiness tester bloke told us, but it was 14-15 years ago and, as I stated, our owners didn't bother for cost reasons. I remember that bloke, because he was paid by Guiness to travel around Europe and test the Guiness being poured at different pubs and his job was to rate them. What a life!

 

[quadbox]

I had not considered the carbonic acid thing MHB, very good info. And I stand corrected on the mechanism for the bubbles.

 

[MHB]

I not long ago finished reading Foam by Charlie Bamforth, its a way more complex subject than I would like it to be.
The physics of bubbles is some what counter intuitive, even the transition between the two types of bubbles is a science in its own right, the role played by protein, alpha acids and diprotic metal ions get added in. Ends being a very complex set of interactions.
Still got a lot to learn
MArk

 

[BJB]

It maybe a problem I have but..I can taste nitrogen in a beer, very easily and I don't really like it.
Don't try to tell me Guiness or any other beer was poured using nitrogen until 10 years ago.

 

[Benn]

Nitrogen gives you the bends, one reason I don't drink draught Guinness at depth.

 

[BJB]

Nitrogen gives you the bends, one reason I don't drink draught Guinness at depth.