High final gravity

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.

Any thoughts?

That’s about 66% attenuation. A little low for that yeast. The starter you made was pretty small. Should have made about a 2L starter. What temp did you mash at? And what temp did you ferment at? Also, how long has it been fermenting?

I’m guessing the size of your starter is to blame, but there are other variables that could have contributed.

Why did you rack to secondary before reaching the desired FG? (warming the beer and rousing the yeast was your best option.) What temp is the beer now? Did you rehydrate the champagne yeast?

When figuring out what size starter to make, use Mr. Malty. Here’s a link

http://www.mrmalty.com/calc/calc.html

There’s also an app you can download to your phone… assuming you have a smartphone.

Mash temperature was 152 for 90 minutes. Fermentation temp was room temp, probably 70. I’ve always racked to a secondary fermenter when activity has slowed appreciably to get the beer off the sediment, and in this case, also for dry-hopping. I did rehydrate the champagne yeast.

The primary fermentation was 7 days, and it’s been 5 days in the secondary.

Thanks for your comments.

The short primary is probably the cause of your stuck fermentation. Leave the beer in primary for at least two weeks and preferably three before even thinking about racking it - and you can dry-hop the last week as well. You won’t have off-flavors from doing this - in fact, you’ll likely make better beer if you let the yeast have plenty of time to clean up after the main fermentation.

Since you added additional yeast (champagne yeast at that) and got no gravity drop, I’d say you have a wort with a lot of unfermentables and your fermentation is finished, not stuck.

I’d wager that the inactive champagne yeast hit the ~7% ABV beer and never even woke up. To have any chance at restarting a stuck fermentation, you should pitch a starter at high krausen.

There’s no reason to use champagne yeast in a beer this small, BTW. Most any ale yeast will get you to at least 12% ABV.

Those certainly added unfermentables, but without the recipe, I can’t say how much.