I made a partial mash Cascadian Dark Ale, a ‘clone’ of Hop In the Dark, which had an original gravity of 1.083, or 11% potential alcohol, but when racked to a secondary, showing little activity, had a gravity of 1.028, or 3 1/2%, way too high. I added champagne yeast thinking the fermentation was stuck, but it didn’t produce additional fermentation.
I had cold-steeped dark wheat malt, black patent malt, and extra dark crystal malt, which were not part of the mash, and i’m wondering if that somehow added unfermentable sugars to the wort that produced this high final gravity.
The mash included 2-row pale, flaked oats, chocolate malt, and Carafa III, and the iodine test showed good conversion. Munich/Pale liquid extract was used in the wort as well. I used Wyeast 1056, American Ale Yeast, making a 1-quart starter.