FG too high after 4 weeks - what do I do?

[BrewingChip]

I brewed a toasted coconut oatmeal stout a little over 4 weeks and am having trouble with lowering my final gravity. Here’s the recipe:

4 GALLON COCONUT OATMEAL STOUT BIAB (7/2/19) (90 minute mash)

• 6 pounds “special pale”
• 1 pound flakes oats
• 1/2 pound Biscuit
• 1/2 pound Caramel/Crystal 60L
• 1/2 pound chocolate
• 1/2 pound roasted barley
• 1/2 pound (3 cups) of flaked sweetened coconut (Toasted at 350 for 15 minutes stirring every 5 minutes)
• 1 ounce German magnum at 60 minutes (60 minute boil)
• US-05 pitched at 70 degrees
• Added 1 pound of toasted sweetened coconut on July 14th (12 days into primary fermentation, removed 3 weeks later)
• Target OG: 1.062 (Actual was 1.060)
• Target FG: 1.010 (Actual was/is 1.024)

When I added the toasted coconut 12 days into fermentation, the gravity was 1.024. Fermentation kicked back up for another day and the airlock was going nuts. I checked the gravity again today (August 4th) and the gravity is still at 1.024. The beer tastes alright, but I am not sure if I should bottle it as is or go out and buy another packet of US-05 or get something different like US-04.

I’m not looking for what I did wrong with this batch... I’m simply looking for someone to tell me what to do at this point in time to make this beer as tasty as possible after this mishap. I would love to get this beer closer to the target 6.9% Abv range instead of its current 4.7% Abv state. Any help or advice is appreciated!!!

 

[RPh_Guy]

Mash temp?

 

[BrewingChip]

Mash temp?

Mash temp was 155 but fluctuated a degree or two through the 90 minute mash.

 

[IslandLizard]

Used a hydrometer for measuring the FG?

 

[BrewingChip]

Used a hydrometer for measuring the FG?

Yup, used my handy-dandy hydrometer. I even used it on plain water and it was spot on at 1.000. What do you think - should I get a pack of yeast and pitch again?

 

[smata67]

S04 is less attenuative than S05, so if you want to add some additional yeast, S05 would be the one to use and keep the character of the original recipe. This is what I would do: boil a cup of water, add 3 oz corn sugar and toss in along with a packet of S05. Stir the yeast up for a few days. Live with whatever results you get.

 

[IslandLizard]

Yup, used my handy-dandy hydrometer. I even used it on plain water and it was spot on at 1.000. What do you think - should I get a pack of yeast and pitch again?

OK, that is good information.
Could something in the coconut have killed/neutralized your yeast?

I doubt pitching just a pouch of dry yeast will change much. I'd make a 1 liter starter with it first, pitch at high krausen, and keep the ferm temps at 70-74F.

Now you may simply have a lot of unfermentables and 1.024 is as good as it gets.

• What is "Special Pale" malt? Could that be part of the cause?
• Are you sure your thermometer reading was accurate? If it reads 5F low, you made a nice chewy dextrin soup.

 

[BrewingChip]

S04 is less attenuative than S05, so if you want to add some additional yeast, S05 would be the one to use and keep the character of the original recipe. This is what I would do: boil a cup of water, add 3 oz corn sugar and toss in along with a packet of S05. Stir the yeast up for a few days. Live with whatever results you get.

I think I will give this a shot. The beer tastes fine so far, but I would like it to pack more of a punch if at all possible. I'll get some S-05 today and see post the results in a few days. Thanks for the tips!

 

[BrewingChip]

OK, that is good information.
Could something in the coconut have killed/neutralized your yeast?

I doubt pitching just a pouch of dry yeast will change much. I'd make a 1 liter starter with it first, pitch at high krausen, and keep the ferm temps at 70-74F.

Now you may simply have a lot of unfermentables and 1.024 is as good as it gets.

• What is "Special Pale" malt? Could that be part of the cause?
• Are you sure your thermometer reading was accurate? If it reads 5F low, you made a nice chewy dextrin soup.

Special Pale was what the original recipe called for, but I believe I just used Pale Malt.

Pretty confident the thermometer reading was accurate. It has served me well so far in my homebrewing adventures.

 

[Dgallo]

What program are you using to calculate? If you plugged in a 155* mash temp for your choice of grains it should have certainly projected higher than 1.010. I personally only think you’re slightly high. Maybe 2-4 points off. Flaked oats aren’t nearly as fermentable as basemaltz and dark grains add very little fermentable sugars. They both will add gravity but they will be mostly unfermentable sugars. When you mash on the higher end this extracts an increased amount of unfermentable sugar.