Multiple batches low attenuation

[jbrew87]

My last few batches have been showing lower attenuation. The first couple batches seem to be related to using some old extract. This last batch I would like some help with.

Grain bill in Lbs:
Pale Malt 8.00
Munich Malt 2.25
Cherry wood Smoked 1.88
Crystal X-Dark 1.10
Pale Chocolate 0.90
Black Malt 0.30
Midnight Wheat 0.30

I mashed at 152-154 degrees for an hour.
Hour long boil.
1.068 OG
I shook the wort A LOT before adding a 1L starter of US-05.

Now it's at 1.019 and showing no sign of activity. I realize there are a lot of un-fermentables in that mash bill, but I was expecting around 1.015. I'm looking for some input.

 

[thehaze]

You have a lot of specialty malts, with no diastatic power and you also kinda mashed high-ish. With that grainbill, I would have mashed at 149F for 60-90 to ensure a more fermentable wort, if I were to want a lower final gravity or maybe I would have added some sugar.

From my limited experience, US-05 does not like the combination of high mash temps. + a fair amount of crystal and roasted malt.

What temperature have you been fermenting it at? Have you raised the temperature to try to force the yeast to chew some more?

 

[jbrew87]

I fermemt at 65 - 68*. Its been in the primary for a week now. I tasted the beer today and it's still a little sweet. I will take another reading in a few days, but all activity appears to have stopped. I have not warmed it up as that should be warm enough for us05

 

[thehaze]

US-05: https://fermentis.com/wp-content/uploads/2017/10/SafAle-US-05.pdf

Ideal temperature range is between 64 and 82F ( 18-28C )
From the description " American ale yeast producing well balanced beers with low diacetyl and a very clean, crisp end palate. "

These alone will make me do a diacetyl rest for US-05 every single time, and 68F would not be enough for most ale yeast to either finish the last points of fermentation or clean after themselves.

But leaving it enough time at 65-68F would probably be OK.

The % attenuation, although low, seem to suggest it is finished due to high mash temp. and amount of unfermentables alone. If you are not in a hurry, you can leave it a few more days and check if gravity changed.