did it kill my yeast?

ok so i started brewing my first big beer on Sept 21st. Recipe as follows...

Imperial stout
9.9 lbs Gold Malt Extract
1/2 lb. Choclolate Malt
1 lb. British Crystal Malt
3/4 lb. Black Patent Grain
1 lb. Roasted Grain
1.5oz mystery hops for bittering
1oz mystery hope for aroma
3.5oz 84% organic dark choc

i rigged up a temp controller for an extra fridge i got and fermented this at 70 degrees using WLP545 yeast http://www.whitelabs.com/beer/strains_wlp545.html everything was going well untill last weekend we got a cold front that came through and dropped the temp down into the 50s,now its back to 70. previous to this i was still getting a burp in the air lock every 40 seconds(Give or take) and now im not getting anything.

my Starting Gravity was 1.082 and when i checked it for the first time this afternoon it was only down to about 1.021. could the cold snap have killed the yeast? or am i just over thinking everything? im going to check the gravity over then next few days and bottle it if theres no change but thought i would get some input from more experienced people.

also now that im here, i haven't found any good input on priming sugar amounts with big beers. any suggestions?

thanks a million guys!!!

Decreasing temps can cause the yeast to shift gears toward dormancy, it won't kill them unless you get them very cold, like below freezing. Get it warmed back up and rouse the yeast either by swirling or with a sanitized device.

Prime with 1oz/gallon of beer will generally give you close to 2.5volumes of CO2.

The cold could have slowed down the yeast but it wouldn't kill them. If you've warmed it back up they should get back to work. I know your FG is a bit high but nothing I haven't seen using extract before. I would say its a good possibility that its finished. Extract generally finishes at a higher FG than All Grain due to the unfermentables created during the process. I'm not positive but I believe LME has more unfermentables than DME at least that seems to be the consensus among extract brewers that have written in complaining/worrying about high FG. I believe the majority of them were using liquid not dried. I'm sure if I'm wrong someone will be by and correct me. I think your beer will be fine though.

GilSwillBasementBrews said:

Prime with 1oz/gallon of beer will generally give you close to 2.5volumes of CO2.

Click to expand...

that's interesting, i havent tried this before. just so i have this straight, your saying i could add 5oz of beer to my 5 gallon batch instead of sugar as a primer before i bottle? what is it about the added beer that makes this work?

helibrewer said:

Decreasing temps can cause the yeast to shift gears toward dormancy, it won't kill them unless you get them very cold, like below freezing. Get it warmed back up and rouse the yeast either by swirling or with a sanitized device.

Click to expand...

yeah i think it will be a good brew no matter what. it smell absolutely amazing! i still want to try and do this by the numbers so to speak. would my original 70 degree mark be good or should i keep it a little warmer till things get going again?

gedion said:

that's interesting, i havent tried this before. just so i have this straight, your saying i could add 5oz of beer to my 5 gallon batch instead of sugar as a primer before i bottle? what is it about the added beer that makes this work?

Click to expand...

I'm sorry I meant 5oz sugar/5 gallons if beer
So you would only need to add 5oz of sugar to get about 2.5 volumes of CO2.

GilSwillBasementBrews said:

I'm sorry I meant 5oz sugar/5 gallons if beer
So you would only need to add 5oz of sugar to get about 2.5 volumes of CO2.

Click to expand...

thanks, im pretty sure i read your original post wrong. but WHEW...im glad i double checked lol.