How to carbonate a coffee beer with nitro?

2 corney kegs of a coffee lager, how would one carb it up for use on a nitro system. Locally we are finding conflicting info.

I would try carbing to about 1.2 volumes then throw it on nitro. You could do that by force carbing at the appropriate temp and pressure, or dose it with enough priming sugar to get you to 1.2 volumes.

You can do what microbusbrwery said, or just hook it up to the beer gas for a couple weeks at temp and serve it up from there. There are a lot of methods for serving nitro, they all work.

Do you mean carb with beergas (nitro) or c02?

A little more explantion needed as I am not experianced...........kinda need step by step. We have a fantastic coffee beer that would be killer awsome on nitro.

Force carbing to 1.2 volumes with CO2, then hook it up to beergas at serving pressure. Or hook it up to beergas at serving pressure and wait a couple weeks (it'll reach equilibrium, but it can take a little while). Or prime to 1.2 volumes and wait a couple weeks before hooking it up to beergas at serving pressure.

Do I want a 60/40 mix or a 75/25.

Local supplier recommends 6040 for everything other than guiness.

I picked up a gas blender off ebay for my setup. It's a Micromatic MM200 and does a 75/25 blend on the fly and it's worked well for me, and it's the only one I've ever used. I thought I remember a BYO article that indicated 60/40 was less than ideal because it tended to result in overcarbed nitro beers, but I can't seem to find the article. Hopefully someone else knows. Maybe it'd work at a lower pressure than 75/25?

microbusbrewery said:

I thought I remember a BYO article that indicated 60/40 was less than ideal because it tended to result in overcarbed nitro beers, but I can't seem to find the article. Hopefully someone else knows. Maybe it'd work at a lower pressure than 75/25?

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I haven't read said article, but I would tend to agree. Of course, it will depend on temperature and pressure, but with most draught conditions a 75/25 or 80/20 is ideal.

OP: get yourself a stout tap, a bottle of 75/25 or 80/20 beer gas, carbonate to 1.5 vol CO2 either with the beer gas or with pure CO2, then serve at about 25-30 psi. You can fine tune from there. I've been brewing and serving nitro beers for years, as well as consulting breweries on how to set up theirs. It's not rocket science, but there is a plethora of misinformation out there.

Lastly, assuming our coffee beer is already carbed with C02 to normal levels you would serve on C02, can the keg be bled down a bit and put on beergas, or do we need to get it flat and then start again.

Fordiesel69 said:

Lastly, assuming our coffee beer is already carbed with C02 to normal levels you would serve on C02, can the keg be bled down a bit and put on beergas, or do we need to get it flat and then start again.

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You could, in theory, bleed the CO2 down to ~1.5 volumes, but it would be difficult to know without measuring it. Without a Zahm, it would be easiest to bleed the carbonation level down to near zero and start over at the proper temperature and pressure to reach 1.5 volumes CO2.

I think I got it now. Lastly, what would happen if it was not exact at 1.5 volumes? Say it was 1.2 or 1.8 just for sake, what would happen. Reason I ask is the keg we want to experiment with is no longer full.

Fordiesel69 said:

I think I got it now. Lastly, what would happen if it was not exact at 1.5 volumes? Say it was 1.2 or 1.8 just for sake, what would happen. Reason I ask is the keg we want to experiment with is no longer full.

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It certainly doesn't have to be exactly 1.5 vols, but that is right in the "sweet spot" for balancing nitro draughts. I'd say you could manage a 1.2 to 1.8 vol beer, but you'll have to adjust pressure accordingly, and it might not pour with desired amount of head. If you anticipate the beer falling to 1.2 before serving, I'd plan on a 75/25 or 70/30 mix if you can, and bump up the pressure to maybe 35 psi. There are variables that I don't have info on, but this is my best guess based on what you've told us. In short: you'll be fine.

Wish me luck. Hopefully will have the stuff for this weekend to try sunday on brewday.

I / we have no method of being able to accuratly carb to any "VOL", as the blichman carb system has a pressure temp chart and that is all we can go by. Frankly I am not even sure how to read it.

"vol" = volumes of CO2. It's a dimensionless unit defined by unit of volume of CO2 dissolved per unit of volume of liquid. So, a beer carbonated to 1.5 volumes CO2 would have 1.5 liters of CO2 per liter of beer - or gallons per gallon, cubic ft per cubic ft, etc.

If you know the temperature of the beer, set your regulator to the corresponding pressure that gives you the desired level of carbonation. It's that simple.