[dzlater]

If I have a a carboy that is @ ferment temp of 68°f
and I am kegging it and then putting it in the fridge @ 45°f and hooking up the gas
when using a carbonation table do I use the 68° or the 45°?

[tygo]

Use the 45F.  It's not going to take more than say a day, maybe less to get to the serving temp and that's the temp that will determine how much CO2 will go into solution. 

[oscarvan]

What he said.

[dzlater]

Thanks that's what I thought.
Somewhere I thought read something about using the highest temp. the beer was at during fermentation?

[morticaixavier]

Thanks that's what I thought.
Somewhere I thought read something about using the highest temp. the beer was at during fermentation?

That is to take into account residual CO2 already disolved in the beer. I don't think it is as much of an issue when force carbing as when priming when the total available potential CO2 is fixed and too much additional priming sugar can cause overcarbing.

[Hokerer]

That is to take into account residual CO2 already disolved in the beer. I don't think it is as much of an issue when force carbing as when priming when the total available potential CO2 is fixed and too much additional priming sugar can cause overcarbing.

+1.  The "highest temp" thing is all about when you're calculating amounts of priming sugar.  For keg CO2 carbing, that's not the case.

[dzlater]

got it thanks

[rbclay]

i have a similar question, but i'm bottling, not kegging.
i plan to bottle an IPA that i have been lagering at 50F in tertiary. i didn't have time to bottle after dry-hopping in a secondary, so i put it in a carboy and put it in the fridge at 50F.
using my widget for priming i need 2.15 oz. corn sugar for 5G to target 2 vol. CO2.
that's for 5G of beer at 50F- which has 1.2vol. residual CO2 in it. this is the first time i've lagered before bottling. when the beer warms towards room temp as i'm bottling, and is at room temp while conditioning, which temp should i plug into the calculator? at 70F, 5G beer has only .83 residual vol. CO2. that would call for 3.13oz. corn sugar.
that's a huge variance.
i've had issues getting consistant carbonation when bottling. i want to get this right. i'd rather err on the side of slighty undercarbed than over.

[euge]

rbclay I think 2.15 oz is slightly more than half of what you need at 70. I've got consistent results using 4 oz for 5 gallons at 70. If you dropped most of the extant yeast by lagering you might need to add yeast at bottling.

[tygo]

i have a similar question, but i'm bottling, not kegging.

What temperature did you ferment at?  You should use the highest temp the beer sat at prior to bottling.  So if you fermented at 65F and then dropped it to 50F after fermentation was complete you would use 65F.  At 65F 4-5 oz is going to give you about 2.5 volumes.  If you're shooting for 2 volumes at, let's say 65, I'd use about 3 oz, maybe just a touch less.

And unless it's been sitting around at 50F for a long time I wouldn't worry about adding additional yeast.  There should still be plenty in suspension.

[rbclay]

Here's the stats:
OG 1072. 15 days primary at 68F. 7 days secondary - dry hopped- at 68F. 17 days tertiary at 50F.
FG 1016.

You should use the highest temp the beer sat at prior to bottling

Yep- that's what I figured. More precisely, the temp during the majority of primary fermentation.

And unless it's been sitting around at 50F for a long time I wouldn't worry about adding additional yeast.  There should still be plenty in suspension

I figured just over 2 weeks was pushing it. 1056 is not a super flocculant strain, and I probably could have gotten away with no bottling yeast, but I did add some Nottingham for insurance. The beer hadn't dropped clear, so I could have taken that to mean there was plenty of yeast still in suspension. As this was the first time lagering an ale and the relatively high OG, I went with some bottling yeast for insurance. I have made many a pale ale at OG 1050-1056 without ever using bottling yeast and had no carb issues.

As always, thanks for the feedback...

[Hokerer]

I figured just over 2 weeks was pushing it.

2 weeks is not even close to "pushing it".  Earlier this month, I bottled a batch after 77 days in the fermenter.  No added yeast and it carbed up just fine.