Carbonation Issue

[Hopzilla]

I've bottle in the past and have had no issues with carbonation other than a few bottle bombs. I've kegged and have had no issues with carbonation. But this time, I ran into an issue.

So I made about a 2gal batch and when it came time for secondary, I put it in my corny keg, and dumped sugar/water solution into the keg. I used the amount of sugar based off an online calculator. It sat for about 3 weeks. I then used the blichmann beergun and bottled the beer. I had enough pressure that I was able to bottle about 7 bottles w/o my CO2 tank turned on (forgot to open the valve). I then capped the bottles and put them in the fridge. Let the sit for about 24 hours and then tried one. It was flat. Only a slight "psh" when I opened it. Any idea why the beer was flat? I thought possibly because I used a 5 gal corny keg and only had 2 gals of beer in there. To much free room.

 

[westwoodciderguy]

What was the pressure in the keg and the temp at time of bottling? It sounds to me like you squirted a bunch of warm flat beer into the bottles with your beer gun :smack:

I feel rude for asking... but why you are trying to naturally carbonate in a keg when you also have a CO2 tank? 2 gallons in a 5 gallon keg would actually work better than a full keg if you were force carbonating with a CO2 tank (more surface area to mingle with the CO2 when you shake that stuff around :rockin

 

[duboman]

So you simply put the beer into the bottles without any co2 on? Whatever amount of co2 was in the keg to push out the beer came out of suspension (asuming it ever was) and you bottled flat beer.

Even if you naturally carb a keg you still need to push co2 to dispense the beer

 

[Dr_Horrible]

I don't think this plan was destined for success from the beginning. The reason bottles stay carbonated is because there's no where for the CO2 to go as the yeast produces it (because it's capped and there's barely any head space), so it infuses in the beer (and the colder the temperature, the more CO2 the liquid can hold).

My guess is that with all that head room (and your secondary fermentation temperature), the amount of CO2 that was actually in the beer was very miminal. It all escaped into the head space and barely any of it actually stayed inside the beer. If you had cold crashed in that keg, the amount of CO2 that ended up in your beer likely would have been a tiny bit more, but probably still less than desired.

The fact that you were able to dispense from the keg into the bottle doesn't mean anything with respect to your beer's carbonation itself. It was merely using the pressure from the CO2 in the head space to force the beer out. It proves that your yeast did produce CO2, but not that it was captured in the beer.

This isn't from experience, just reasoning it out in my head, so I could be misspeaking.