Brewing a Russian imperial stout, it's has been bubbling for about three weeks. It looks like it has stalled, and is reading 1.031 and I'm looking to be at 1.018. I have read a couple of threads that I should bring up the temp. and give it a little shake to bring back the yeast to get where I want to be. Should I do this? Any other thoughts to get the FG to where I need to be!