Nitrogen questions

[Andy_K]

I love a good nitrogen beer with a thick, creamy head and less bite, so I bought a nitrogen tank and stout faucet for my kegerator. I assumed it was as easy as hooking it up at upper 20's PSI and pouring a beer from my previously carbed kegs.

I just poured my first pint and it was all head - the cascading effect was very weak, and within minutes the head was completely gone. The bubbles were big enough to see almost all of them. It never had the creamy look on top. I thought it was a fluke so I've tried several times since then.:cross: I'm basically just drinking flat beer.

I assume that my keg is overcarbonated - It's force carbed around 40 degrees for months at 8 PSI. So that means I'm around 2.1 volumes CO2, and I've read that I should be around 1.2 volumes CO2. Is that the reason for the lack of head retention, and creamy nitrogen pour head?

Second question - I saw a sticky to blow out the CO2 from an overcarbed keg....If I do this, and then leave a 75%N/25% CO2 beer gas mix sitting on my keg at 28 PSI, will I be doing the same thing as force carbonating the beer at 7 PSI? (28*.25=7)
If that's the case, i'll need to 1)disconnect my nitrogen mix after I'm done drinking, or 2)turn down the pressure on the nitrogen regulator. This would be annoying to have to adjust every time, so I hope someone tells me this isn't necessary.

Third question - Should all styles of beer be carbonated to the same volume when using a nitrogen system, or should they be different?

Thanks for your help guys, cheers!

 

[Swiller]

You want to carb 1.2 to 1.8 then serve on nitro around 25-30psi

 

[Andy_K]

Thanks, so my volumes CO2 are too high. But is that the cause of the problem? Could it be my stout faucet, which is brand new and a cheap one (Krome) with a bad restrictor plate? Those are the only 2 problems I can think of...

 

[beergolf]

You want to carb 1.2 to 1.8 then serve on nitro around 25-30psi

This is what I do. I carb it up with CO2 and then hook it up to the beergas. I use 30-35 lbs. Nice pour, cascade and head.

 

[Andy_K]

Do you leave the beergas hooked up to the keg turned on?
How would you calculate CO2 volumes using on a nitrogen/CO2 beergas mix. Mine is 75/25, so will that mean at 30 PSI it's the equivalent of 7.5 PSI CO2?

If that's accurate, unless you shut the gas off or serve it warm, leaving it on at 30 PSI could take your CO2 volumes up to 2 or 2.1. And that's the pressure that I'm having trouble with creating all head and no real cascade.

 

[Swiller]

Use pure co2 to carbonate. Use a carbonation chart to determine temp/pressure for proper volume. Don't use beer gas to carbonate, it's a waste. Just use it to serve.

 

[day_trippr]

^ That's the right way to do it...

Cheers!

 

[beergolf]

Use pure co2 to carbonate. Use a carbonation chart to determine temp/pressure for proper volume. Don't use beer gas to carbonate, it's a waste. Just use it to serve.

Yes, do this........

 

[LLBeanJ]

Do you leave the beergas hooked up to the keg turned on?

Yes

How would you calculate CO2 volumes using on a nitrogen/CO2 beergas mix. Mine is 75/25, so will that mean at 30 PSI it's the equivalent of 7.5 PSI CO2?

Correct. 30 PSI @ 75/25 N/CO2 = 7.5 PSI @ 100% CO2

If that's accurate, unless you shut the gas off or serve it warm, leaving it on at 30 PSI could take your CO2 volumes up to 2 or 2.1. And that's the pressure that I'm having trouble with creating all head and no real cascade.

If 30 PSI does not work for you, lower it. There is a point where you will get the proper cascading nitrogen head on your system. You need to do a little trial and error experimentation to figure out where that point is. It may take a while and you may get frustrated, but you will get there.

 

[Andy_K]

I've got a new stout that will be ready to keg in a few weeks...judging by a carbonation table, if I seal up the keg at room temp and let it cool around 40 degrees, it will be 1.4 volumes CO2 after about 2-3 weeks, which is acceptable for a nitrogen pour. That means I wouldn't even need to hook it up to any pressure.

Would you guys agree with that logic?

I realize that most stouts serving temp should be 50-60 degrees but I'm not going to put it in a separate kegerator from my other brews...

 

[Swiller]

I've got a new stout that will be ready to keg in a few weeks...judging by a carbonation table, if I seal up the keg at room temp and let it cool around 40 degrees, it will be 1.4 volumes CO2 after about 2-3 weeks, which is acceptable for a nitrogen pour. That means I wouldn't even need to hook it up to any pressure.

Would you guys agree with that logic?

Wait, you mean seal it up and let it ferment/carbonate at the same time? 40 degrees will slow the fermentation down, so it'll take a while to finish...if at all.

If you are fermenting under pressure, I guess you could do this at room temp. I do it sometimes since I ferment under pressure, but I calculate my target gravity to get the co2 volume I want. I also ferment in a controlled temp chamber. When I hit the gravity number associated to my fermentation temp, I close my spunding valve or remove it.

Unless you have the equipment, you're better off just finishing the fermentation, hooking up the co2 and then nitrogen... Especially since your original post was about having problems with foaming. Doing it this way gives you better control of your final product. But feel free to try it the other way and bash your head against the wall thinking it's your faucet with the issues vs your technique. But that's just my 2¢

 

[Andy_K]

Sorry I wasn't very clear, it's almost fermented out completely and it's in the secondary...I'm wondering once it's completely fermented out, if I keg it and seal it up and cool it to that temperature, do I need to even apply any CO2 pressure to reach such low volumes of CO2. Judging by the keg carbonation calculator on Brewer's Friend, 1.5 volumes of CO2 is yielded at 36 degrees farenheit, with zero pounds of pressure applied.

http://www.brewersfriend.com/keg-carbonation-calculator/

 

[Stealthcruiser]

Yes, you will need to force carbonate it.

It won't build anything of mention, unless it's NOT done fermenting, but that still won't be enough.

Do like was mentioned, carb to your desired level, and lay the beer gas to it.

They said it will take a little trial and error to get it "dialed in".

 

[LLBeanJ]

Since this is your first nitro brew that you are starting from scratch with no carbonation, I would use the beergas to carbonate it. Put it on 24 PSI for 2 weeks and if that does not give you a proper cascading foamy pour, increase the pressure by 2 PSI per week until you get there. The idea is to sneak up on it and give it time to absorb the additional CO2 as you increase the pressure. Once you figure out the sweet spot for your system, you can use that knowledge to know how much to pre-carb with straight CO2 next time. As an example, if the nitro sweet spot is 28 PSI, then you would know to pre-carb with CO2 at 7 PSI (28*.25 = 7).

 

[zachattack]

Sorry I wasn't very clear, it's almost fermented out completely and it's in the secondary...I'm wondering once it's completely fermented out, if I keg it and seal it up and cool it to that temperature, do I need to even apply any CO2 pressure to reach such low volumes of CO2. Judging by the keg carbonation calculator on Brewer's Friend, 1.5 volumes of CO2 is yielded at 36 degrees farenheit, with zero pounds of pressure applied.

http://www.brewersfriend.com/keg-carbonation-calculator/

Remember that's gauge pressure. If you're applying 1 psig of CO2, it means you already have one atmosphere (14.7 psi) for a total CO2 pressure of 15.7 psia. So that 0 psi number means that you maintain a headspace of 100% CO2 at atmospheric pressure.

 

[Yooper]

Sorry I wasn't very clear, it's almost fermented out completely and it's in the secondary...I'm wondering once it's completely fermented out, if I keg it and seal it up and cool it to that temperature, do I need to even apply any CO2 pressure to reach such low volumes of CO2. Judging by the keg carbonation calculator on Brewer's Friend, 1.5 volumes of CO2 is yielded at 36 degrees farenheit, with zero pounds of pressure applied.

http://www.brewersfriend.com/keg-carbonation-calculator/

It needs to carb up. If you add priming sugar to it, it will carb but it needs to be at a warmer temperature for the sugar to do the job. OR you can put it on the c02.

If you apply 0 pressure to the beer, you'll have 0 carbonation. Those (fairly useless) tables assume that the residual c02 in solution will do the job, but the beer isn't being fermented at 40 degrees. Use the correct temperature, which is the fermentation temperature, and you'll see that 0 psi will give you 0 carbonation.

 

[ajdelange]

Remember that's gauge pressure. If you're applying 1 psig of CO2, it means you already have one atmosphere (14.7 psi) for a total CO2 pressure of 15.7 psia. So that 0 psi number means that you maintain a headspace of 100% CO2 at atmospheric pressure.

This also has to be taken into account when doing the partial pressure calculations. If the mix pressure is 30 psig thats 45 psia (44.7 actually) and, in a 25% mix, the partial pressure of CO2 is then 25% of 45 or 11.25 psia which is actually a negative gauge pressure.

To carbonate stout you want about an atmosphere (15 psia = 0 psig) of CO2. I get this either by applying 25% mix at 60 psia (45 psig) or by using straight CO2 at just enough pressure to move the pin in the gauge and then raise the CO2 pressure enough for the faucet when I serve (no nitrogen needed).

I got some great charts from McDantim a few years back but they seem to have replaced those with some Excel spreadsheets which are available at
http://mcdantim.com/distributor-tools/calculators/

 

[trent_77590]

I just traded my extra CO2 tank for a nitrogen one. Do you actually need beer gas or can you use straight nitrogen?

 

[day_trippr]

Good question.

As a keg empties the head space increases.
Due to the partial pressure gas laws, if you were to fill that increasing space with straight nitro, the beer would start losing carbonation proportionate to the increased space - like the nitrogen wasn't even there. That last pour might actually be flat once the nitro dissipates.

So, an answer would be "It's not ideal"...

Cheers!

 

[LLBeanJ]

+1 ^^^^^^^

The beer cannot absorb nitrogen. The nitrogen is only used to push it through the system. In order to push it through the stout faucet's restrictor plate with enough force to create the cascading head, it needs to do so at ~30 PSI. The 25% CO2 in the beer gas is there strictly to maintain proper carbonation.

You can actually achieve the cascading bubbles and creamy head with straight CO2 by carbing to ~7-ish PSI, cranking it up to 30 PSI to push thru the stout faucet, then bleeding the keg back to 7 (or wherever it was) in order to preserve the low carb level. Obviously, this is a huge waste of CO2, not to mention a real PITA, so we use beergas instead.

 

[trent_77590]

Well ****

 

[BBBF]

http://www.ebay.com/itm/PERLICK-GAS-BLENDER-/251640551737?pt=LH_DefaultDomain_0&hash=item3a96f21939

I bought one of these. I haven't hooked it up yet, so I can't give a review of how well it works.

 

[Andy_K]

This also has to be taken into account when doing the partial pressure calculations. If the mix pressure is 30 psig thats 45 psia (44.7 actually) and, in a 25% mix, the partial pressure of CO2 is then 25% of 45 or 11.25 psia which is actually a negative gauge pressure.

To carbonate stout you want about an atmosphere (15 psia = 0 psig) of CO2. I get this either by applying 25% mix at 60 psia (45 psig) or by using straight CO2 at just enough pressure to move the pin in the gauge and then raise the CO2 pressure enough for the faucet when I serve (no nitrogen needed).

I got some great charts from McDantim a few years back but they seem to have replaced those with some Excel spreadsheets which are available at
http://mcdantim.com/distributor-tools/calculators/

These spreadsheets are very helpful, thanks. However I've realized now unless I keep my beer VERY cold, if I want around 1.5 volumes co2 in my beer, and be able to leave beergas alone at serving pressure (25-30 psig), I shouldn't be using a 75/25 N2/C02 mix, rather something like 60/40.

That's unless you guys think 45 psig may work for serving a pint of stout.

 

[ajdelange]

As I noted earlier McDantim used to produce charts and I have one of those but it's in Virginia and I am not. IIRC the correct volume for Guiness is 0.8 Vols so a lower pressure of 25% beer gas can be used.

 

[LLBeanJ]

+1 ^^^^^

The carbonation present in a nitro brew should be slightly north of flat.

Set the pressure to give you a proper pour, i.e., ~30 PSI. Don't worry about the carb level, as it will be close enough if the pour has the right amount of foam/cascading head. Too much foam? Your pressure/carb level is too high. Not enough foam? Your pressure/carb level is too low. That's all you need to know.