Trouble with Terminal Gravity

What did you measure attenuation with? Although it is a good idea to believe your measurements, are you sure it was an accurate measurement? Could something have thrown it off? If not pitch some neutral high attenuator like US-05, (imho).

 

What does it taste like? If it doesn't taste like it's finished, the US-05 couldn't hurt.

 

It probably needed more time. You chilled it down before it was finished. If you warm it back up and swirl like mad and then leave it alone for another 2-3 weeks, it should finish. Otherwise, just leave it alone and enjoy it for what it is.

 

I have only used London Ale III twice and both times have finished way above expected gravity. My Wee Heavy finished .02 above expected and a recent NEIPA-ish brew has if currently at .018 above expect. I guess I could leave the IPA for another week, but it is only going to get colder where I am and might not stay above 64 degrees in the house at all times. It is one of those yeast I am thinking about avoiding in the future.

 

They probably took a deep liking to the maple syrup addition, which was simple and crack-like for them and they got lazy after finishing with it.
Doesn't look particularly big going by your og, but. WIth your gravity stalling out in the 1030 range like it did. That seems like a probable cause for them pooping out on you.

 

Average attenuation when I use it is about 76%, which is pretty great IMHO.

 

So two smack packs, and no starter? That could be part of your problem. Sounds like you underpitched a little.
I agree with the above comment too, you should have given it more time in primary.
You probably still have a decent beer, as is though. I would leave alone.

 

I would say possible under pitch. When I just did my recent NEIPA DIPA OG was predicted at 1.076 and yeast calculator estimate 286bil cells needed. If you only used 2 smack packs that's less than 200bil cells (at most 200bil if yeast was not even a day old). I made a 1.75 liter starter and pitched about 290 bil cells. My OG ended up being 1.074 and final was 1.016 (1.018 was predicted using brewcipher)

*edit* I also used London ale III 1318

 

I personally find London ale III to perform very well and fast if pitched at the proper rate

 

What was your mash like? I.e., single infusion vs. step, temperature, length.

ETA: You could also try to force-ferment a small sample before adding US-05 to the whole batch, if you haven't already.

 

What were your grain bill, mash temp, and mash length?

 

So perhaps this is something I just haven't learned/encountered yet. I have always been a 1 pack guy. Every beer I have made has only used one pack of yeast regardless of style (except the few horrid experiences I had with starters). Thus far only Windsor and London Ale III have had this much of a difference as far as final gravity for me is concerned. Perhaps I need to pick and choose a little better when/where I use a starter or two packs of yeast. If under pitching is my issue, as it is seemingly with the OP, then this might be a fun experiment for me to work out over the next few years.

 

Putting your recipe (without the syrup) into BrewCipher and adjusting efficiency to get 1.078 OG, it predicts 1.027 FG. (I assumed 60 minute mash)

Adding 1.19 lbs maple syrup (@100% apparent attenuation) brings OG to 1.085 and FG remains at 1.027.