Advice Needed on Yeast

[Ramarok]

So I brewed a sweet stout almost 3 weeks ago. OG was 1.075 at 6 gallons into the fermenter and hit all my numbers/temps. I pitched 2 packages of re-hydrated US-05 at 70F and lowered the temp to 66F in my temp-controlled fermentation freezer. Fermentation kicked off within 8 hours and remained strong for 5 days and then appeared to stop. I let it sit for another week before taking a sample and it was showing 1.034. Raised the temp to 69F and gently stirred up the yeast back into suspension, and waited 2 additional days and took another sample and it still sat at 1.034.

Let it sit for another 4 days and still at 1.034 after that, so I re-hydrated and pitched a packet of K1-V1116 I borrowed from a friend. It's now been 3 days and still no activity and gravity is holding at 1.034.

Don't get me wrong, the samples taste excellent, just a little too sweet. Any advice for getting this thing down maybe at least 10 points?

Recipe Specifications
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Boil Size: 7.88 gal
Post Boil Volume: 6.50 gal
Batch Size (fermenter): 6.00 gal
Bottling Volume: 5.75 gal
Estimated OG: 1.075 SG
Estimated Color: 39.6 SRM
Estimated IBU: 26.8 IBUs
Brewhouse Efficiency: 75.00 %
Est Mash Efficiency: 78.5 %
Boil Time: 60 Minutes

Ingredients:
------------
Amt Name
8 lbs Pale Malt (2 Row) US (2.0 SRM)
2 lbs 8.0 oz Munich Malt - 20L (20.0 SRM)
1 lbs 4.0 oz Caramel/Crystal Malt - 60L (60.0 SRM)
1 lbs 4.0 oz Oats, Flaked (1.0 SRM)
1 lbs Barley, Flaked (1.7 SRM)
1 lbs Chocolate Malt (350.0 SRM)
8.0 oz Black Barley (Stout) (500.0 SRM)
1.00 oz Goldings, East Kent [5.00 %] - Boil 60.0 Hop
1.00 oz Goldings, East Kent [5.00 %] - Boil 45.0 Hop
1.00 Items Whirlfloc Tablet (Boil 15.0 mins)
1 lbs 4.0 oz Milk Sugar (Lactose) [Boil for 15 min]
1.00 oz Vanilla, Pure Extract (Boil 5.0 mins)
2.0 pkg Safale American (DCL/Fermentis #US-05)


Mash Schedule: BIAB, Medium Body
Total Grain Weight: 16 lbs 12.0 oz
----------------------------
Name Description Step Temperat Step Time
Saccharification Add 9.3 gal of water at 157.1 F 153.1 F 60 min
Mash Out Heat to 168.0 F over 7 min 168.0 F 10 min

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[stpug]

If those are hydrometer readings then it sounds a bit high for a normal sweet stout.

If those are refractometer readings then maybe you're not adjusting for the presence of alcohol (i.e. using a calculator).

Wine yeast won't do much, if anything, to malt sugars - they eat simple sugars (which the US05 started with ) and I doubt there's any left at this point.

 

[Ramarok]

Yes they are hydrometer readings. I guess I should have specified its was supposed to be an imperial sweet stout. I was going for @8% or so. It may just be done then at 5.6% but I was hoping for more.

 

[stpug]

Was that Briess 20L Munich malt? If so, I have read that some folks say it contributes a sweetness (i.e. unfermentables) much like crystal malt would. I've used Crisp 20L munich but did not get that effect. I have some Briess 20L to use, but I haven't yet so I have to go off of what I've read elsewhere.

The chocolate and black barley are largely unfermentable as well; though I wouldn't expect a whole lot of sweetness from them. More complex sugars usually have less "sweet" factor to them; probably some dark sugar flavors (molasses, burnt sugar, etc) and mouthfeel.

Lastly, I just noticed the 1.25 lbs of lactose sugar. This is nearly 100% unfermentable (i.e. permanent gravity points) and will contribute a sweetness to the overall brew (plus mouthfeel and maybe creaminess).

Still, I would have expect several points lower as a final gravity (maybe 1.025/26). Did you aerate/oxygenate this batch really well?

 

[Ramarok]

Yeah I aerated pretty well. Had a nice layer of foam from shaking the fermenter. I'm truely wondering if the 60 minute mash wasnt enough to get full conversion and I ended up with too many complex sugars as a result. I didn't do an iodine test at the end of my mash so I guess I'll never know for this batch. I'm going to let it go until this weekend and if it hasn't changed I will go ahead and bottle and call it a learning experience.

 

[stpug]

There are a few options you could try to bring down the gravity a bit, but I don't know if they're worth the effort. If the beer is drinkable then it might be easier to just keep it as-is and do differently next time.

Things you could try:
-Pitching a more attenuative, and less flocculant, yeast strain at high krausen. A belgian/saison strain might work well for this. Due to the few gravity point it would chew up you are unlikely to get any belgian characteristics from it.

-Use some brett yeast as a secondary strain and set your beer aside in a carboy for several months (6-12 months). It will likely eat up some of those sugars and you're likely to get some of the brett characteristic of the strain you choose (barnyard; cherries; sour; etc). I currently have a "too sweet" old ale sitting in a keg with some Orval dregs (Brett Brux) and will check it around the new year but don't expect much until closer to March next year.

-After transferring a beer off of a yeastcake, you could add some oxygen to the fermenter, shake it up to help incorporate the oxygen into the yeastcake, let it wait a couple hours, and then transfer your stout onto the yeastcake and cross your fingers that it eats a few more sugars. You would want to do this on a yeastcake whose attenuation has a reasonably high percentage.

I'm sure there are more ideas but those are a few think think about.