It depends on how you mashed. I've been using WY Old Ale Blend in my imperial stout the last couple years. I would mash the 1.120 beer at 158. the sacch would take it down to about 1.040-1.045 then it would slowly attenuate to 1.024ish. So it depends on how aggressive your boil down was and so forth but my wort is decently unfermentable for use with this yeast.
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