"Smoky" off flavor diappeared, came back...

[TheHappyHopper]

So I brewed this beer back on 7/27/16:

Chocolate Cream Stout
OG 1.060, FG 1.022, 33 IBUs, 36 SRM

7.125 lb Maris Otter
15 oz Crystal 60L
15 oz Chocolate Malt (350L)
4 oz Midnight Wheat
15 oz Flaked Oats
17 oz Lactose
0.75 oz Magnum hops at 60 min
1.7 oz Cocoa Nibs, soaked in rum for a week before adding to the fermenter to sit for another week before kegging.

Fermented with US-04 (1 pint slurry repitched from previous batch) at 64.4F (18C).

Water was tap water, treated with Campden and Gypsum/Calcium Chloride as needed per Bru'N Water.

8/18 - kegged, did not note any off flavors - I noted that it seemed slightly different from the previous batch, but figured it was due to minor changes in the recipe.
8/26 - filled a growler and took to my club meeting. I knew something was a bit off, but I couldn't put my finger on it. I got comments that there was a faint smoky taste - after having it pointed out, I could definitely taste it.
8/27 - took a sample from the keg again, just to make sure it wasn't somehow glassware/growler related, still tasted strongly of smoke.
8/31 - took a sample and it tasted MUCH better, could not detect smoke flavor at all.
9/7 - tastes great, I'm much happier with it.
(Sometime between these notes, I cleaned my keg lines and moved the kegs around in my kegerrator to make room for another keg)
9/12 - took a sample and the awful smoky flavor is back and strong as ever.

At this point, I am not sure what to think. The off flavor showed itself, disappeared, then came back. The only thing I can think of is that the yeast that has settled to the bottom of the keg is causing it. The off flavor cleared up, the keg got moved a bit, and now it is back. This is supposed to be for a beer fest this weekend - at this point I am thinking of dosing the keg with some vanilla extract to help cover it up, that seems to work well when I serve it in a glass.

 

[porterpounder]

What kind of smoke? Yeast derived phenolic band-aidy peat smoke flavors could be the issue. If another kind of smoke I got nothin.

 

[TheHappyHopper]

What kind of smoke? Yeast derived phenolic band-aidy peat smoke flavors could be the issue. If another kind of smoke I got nothin.

Thank you for the response!

I'm not quite sure the best way to describe it - it definitely doesn't remind me of band-aidy. I'm not sure if I'm familiar enough with the peat smoke flavor to label it as that. My first thought was "kind of like a charcoal-y like smoke", but I don't think that's 100% accurate either.

I ended up adding a tablespoon of vanilla extract to the keg. I took a sample last night and the vanilla did a nice job of neutralizing/hiding the flavor, without having the vanilla become too evident. It's at least at a point where I am okay with the batch - It's certainly not my best, but I'm not embarrassed to serve it to others at a beer fest.

 

[Denny]

Infection can cause a smoky phenol.

 

[BreezyBrew]

Infection can cause a smoky phenol.

Is there a way to tell if it's infection or the something else that's supposed to be there?

I seem to get something similar only when I use Weyermann dark roasted grains.

 

[TheHappyHopper]

Is there a way to tell if it's infection or the something else that's supposed to be there?

I seem to get something similar only when I use Weyermann dark roasted grains.

I looked back through my notes since I have had this off flavor once before; both times it has been with a stout. However, I used Briess' Midnight Wheat in both of my cases; but I don't think that has anything to do with it since I have used that malt successfully in batches that have turned out good. But maybe someone with more experience with Weyermann can chime in.

 

[Beernik]

The one time I used roasted wheat (6oz in a 9.5 gallon brew) I would occasionally get an ashy flavor in some of the bottles.