Your Imperial Stout is way out range for the style. Your O.G. must be 1.162 which is way high for an Imperial Stout (normal range is 1.075 to 1.115).
If you get it down to the range of an Imperial Stout I brewed on New Years Day, (1.022), you will end up with a beer with over 18% Alcohol by Volume.
Let's see your recipe for this libation.
3 lbs. American 6-row Pale info
4 lbs. American 2-row info
.5 lbs. Weyermann Carafa III® info
.5 lbs. American Caramel 80°L info
1.5 lbs. Belgian Special B info
3 lbs. Dry Amber Extract info
.5 lbs. Dry Extra Light Extract info
1 lbs. Candi Sugar Dark info
1 lbs. Oats Flaked info
.5 lbs. Barley Raw info
1 oz. Cascade (Pellets, 5.50 %AA) boiled 45 min. info
.5 oz. Centennial (Pellets, 10.00 %AA) boiled 75 min. info
.5 oz. Nelson Sauvin (Pellets, 11.00 %AA) boiled 3 min. info
Yeast : White Labs WLP099 Super High Gravity Ale info
but this wasnt a normal 5 gallon batch. i started with about 7 gallons and boiled down to about 2.5.
I brewed in february and it has aged until september on bourbon oak chunks and now it is aging on sauvignon oak chunks for 14 more months.
thanks for any more input!