Downsides to N2 Tanks/Guinness Gas?
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Compressed CO2 is a liquid, whereas compressed N2 is a gas. There is much more material per unit volume in a liquid vs. a gas (even a compressed gas.) I could do the math, but I'm feeling lazy tonight after a long brew day.
Can't answer the number of kegs question. But with beer gas (mixed CO2 & N2), you (should) carbonate with pure CO2, so you only use the beer gas to serve, which reduces consumption compared to carbonating and serving. You certainly don't want to be purging kegs with beer gas.
Brew on
Stealthcruiser
Well-Known Member
6
MagicMatt
Brewmathemagician
Please correct me if I'm wrong (I love learning!), but I thought the whole reason for using beer gas is because you actually want the N2 to diffuse into the beer while carbonating. I was under the impression that the restrictor plates in the stout faucet causes the N2 (and some CO2, but N2 is less readily diffused) to come out of solution, causing the tiny micro bubbles. If anything, I would have thought the advice would have been to carb with beer gas, but serve with CO2.
Therefore conversely, I would think that if you carbed with just CO2 and then used the beer gas to push, wouldn't just the CO2 come out of solution at the faucet (since no N2 has had time to diffuse into the beer), which would just cause a lot of normal looking foam?
Well, I'm certainly not the expert here but I'll give this a go...
ALL of the carbonation is from CO2. The nitrogen is basically an inert "filler". It's purpose is to let you crank up the pressure in the keg. What you are doing at these higher pressures is keeping the CO2 dissolved at the same volumes without over-carbonating. This allows you to use the higher pressures to push past the restrictor and create the finer bubbles. But your CO2 stays at the lower levels required for proper carbonation of the beer.
Someone correct me if I'm wrong.
MagicMatt
Brewmathemagician
Not that I'm saying you're wrong, but this article would seem to indicate that carbing with beer gas is the desired element:
http://www.craftbeer.com/craft-beer-muses/good-beer-gas-nitro-beers-explained
http://www.craftbeer.com/craft-beer-muses/good-beer-gas-nitro-beers-explained
I'm no nitro expert, but I'm pretty sure you can carbonate a "nitro" beer with pure CO2, and then serve it on beer gas. It takes a decent amount of pressure (high PSI) to push beer through a restrictor plate (what is found inside a stout faucet), this is where beer gas comes in to play. Because nitrogen doesn't dissolve into liquids very well, you can crank up the PSI with beer gas without worrying about over carbonating your beer because there is a smaller percentage of CO2 in beer gas versus pure CO2.
fwiw, I always carb my stouts on straight CO2.
When a keg makes it to the stout tap in the keezer it goes on 70/30 beer gas at 35psi and stays there until it kicks....
Cheers!
When a keg makes it to the stout tap in the keezer it goes on 70/30 beer gas at 35psi and stays there until it kicks....
Cheers!
The solubility of CO2 in beer (water) is about 68 times the solubility of N2 on a volume basis. So, with 75/25 (N2/CO2) beer gas you will get about 23 times more volumes of CO2 in the beer vs. CO2. So, if you have 1.2 volumes of CO2 in your stout, you will only have about 0.053 volumes of N2. Can't see how that will give you N2 based foam, since the overwhelming majority of the gas coming out of solution and creating foam will be CO2.
There is an incredible amount of BS published about N2 and beer. There are not many chemists or physicists writing about beer apparently. From my analysis above: the statement "A typical nitrogenated beer contains about 70 percent nitrogen and 30 percent carbon dioxide." is just plain wrong. It's not even close to reality.
@NeoBrew has the right idea.
Brew on
MagicMatt
Brewmathemagician
Thanks for the info. So nitrogen has absolutely no part in creating the dense head that we typically see with the stout. So, slightly off topic, but what's the deal with the widgets in beer cans then? I would assume that if the N2 was just to allow a higher PSI pour, it wouldn't be needed or useful in a can application.
The widget is basically a foam generator. It is probably engineered to create smaller bubbles than a normal pour generates. The N2 insures higher pressure in the cold can than you would have with just CO2, and that makes the widget a better foam generator. The beers are also probably designed to have much more stable heads, so the normal consolidation of small bubbles into large bubbles is slowed way down. The N2 might play some role in the foam creation, but it is only about 5% of the gas coming out of the beer. The low carbonation typical of beers served on N2 has a major effect on the flavor perception as you don't have as much carbonic acid bite.
Brew on
https://www.homebrewtalk.com/showthread.php?t=453918
Some people on this thread here claim they are getting the guinness cascade off of 100% nitrogen ( I don't particularly beleive it myself )
Given they are doing coffee and not beer.
I myself both carb and serve with beergas. (70/30 mix)
My system has a leak SOMEWHERE in it so i unhook the gas after carbing but will hit it if the `pour` becomes slow/lacking head.
Usually it comes out 90% foam at first, then eventually get's that magic cascade pour for about 2 pints, then starts running slower with lacking head even without tilting the beerglass. Doing this i want to say i've burned through at least 10 corny kegs sinse my last refill.
Some people on this thread here claim they are getting the guinness cascade off of 100% nitrogen ( I don't particularly beleive it myself )
Given they are doing coffee and not beer.
I myself both carb and serve with beergas. (70/30 mix)
My system has a leak SOMEWHERE in it so i unhook the gas after carbing but will hit it if the `pour` becomes slow/lacking head.
Usually it comes out 90% foam at first, then eventually get's that magic cascade pour for about 2 pints, then starts running slower with lacking head even without tilting the beerglass. Doing this i want to say i've burned through at least 10 corny kegs sinse my last refill.
Checked out that thread, and the experiences with pure N2 seem to be mixed, and conflicting. Since it's all anecdotal, with no fundamental science behind it, I'm not ready to buy into the pure N2 being a workable process. With 45 psi of pure N2, you might get something on the order of 0.08 volumes dissolved. Can't see how you could get any kind of head from that.
Brew on
boombrewer
Well-Known Member
When I lived in CA I couldnt get beer gas so I was forced to carb with just CO2 and serve on straight nitrogen. It took a little fiddling but I managed to get the beer carbd just right with the CO2 and serve the whole keg on N2 getting the nice cascade and typical stout head for every pour. I cant speak for the science, but I know it can be done. I actually am just now switching to beer gas after 4 years of running my previous set up. Which is why Im searching old threads trying to remember the ins and outs of using beer gas.
