Stalled Imperial Stout

[vitaminb]

Hi everyone,
A while ago (at this point) I cooked up a batch of Imperial Stout that started at about 1.085ish and was supposed to end up around 1.02. The problem is that after the first few weeks it was stuck at 1.032 or so. I read somewhere that sometimes using the standard 5 gal yeast tubes can be insufficient for higher gravity beers, so they recommended adding more yeast to bring the number down.
That didn't work. So what should I do now?
Thanks.

 

[Quetzolcotl]

1. warm up beer by placing it in the warmest part of your house to get the temp up 5-10 degrees 2. rouse the yeast by shaking the carboy several times a day. If this doesn't kick the yeast back in there is some enzyme you can add that will help start the yeast again but the name escapes me. Also go head and put on a normal air lock instead of a blow off tube if that is what you have on there.

 

[sptaylor70]

What yeast(s) did you use? Is it an extract, PM, or AG brew? Did you aerate or oxygenate the wort first?

 

[MaxStout]

What was your mash temp? Higher mash temps will leave more unfermentables, and result in a higher FG.