Scotch ale stuck like scotch tape

My wee heavy is a wee too heavy. Two 'Final' Gravity measurements one week apart read 1.030.

The details of the case:

- Mashed @ 156
- Fermented @ 66-70 per sticker on side of carboy. (Best I could do during 80 degree days using fan, wet t-shirt and tub o’ water.)
- OG = 1.081
- Used mostly Golden Promise base malt + 1 lb amber malt + 5% other specialty grains (Spec. B and roasted barley)

I racked it from the primary a week after I brewed. Pitched the entire yeast cake from a 70 shilling I brewed the week prior, so yeast cell count shouldn’t be a culprit.

I use that doohickey which sprays the wort as I siphon it from kettle into carboy, and then I shake vigorously in a 6.5 gallon carboy for 2-3 minutes.

Why stuck? Racked too soon? A lack of O2? As far as aeration, I don’t think I can do better than I’m doing now with what I have. (How many folks around here inject pure O2 with a stone before pitching?)

And just as importantly, what to do about it now? I’d hoped to see 69-70% attenuation, and a FG of 1.025’ish. Will a 1L dry yeast starter on a stir plate work to help get it down another 4-5 points? If so, what yeast?

Thanks!

well first suggestion would be to pour in another vile (or packed) of the same yeast you used in the first place or one with a higher alcohol tolerance. next time don't rack for 2 weeks after pitching. just because the bubbles stop doesn't mean fermentation is over.

aeration is for the initial push of yeast growth. i would NOT recommend aerating now. it would cause oxidation and your beer would taste like cardboard. you could get a fish take aerator, inline air filter, and air stone and use that to aerate your wart.

from what i've read this is a better approach than using pure O2. supposedly using O2 makes the beer seem like "a smaller beer". if this is true my guess would be that other gasses get dissolved in the wart and affect the taste.

My vote is for racking too soon.

Seems like you can accpt the beer as it is, or pitching a starter of alcohol tolerent yeast at high krausen.

I would add that you should mash lower next time. Big beers stress yeast, if you want better attenuation make the sugars easier to eat. You could add a clean ale yeast that ferments more vigorously as has been mentioned. I'd probably make a starter and pitch it at high krausen.

Another method I read about here would be to rack this one onto the cake of another somewhat similar beer, if you have anything else going in the pipeline at the moment.

The mash is the only culprit here. Yeast use oxygen only in the replication stage. There would have been only a small amount of replication required to reach full population since you pitched on a prior cake.

That beer is done fermenting fermentable sugars. That mash temp you used is by its nature going to perform on the low side of attenuation numbers. This is the reason to use a mash higher than 154. To lower the attenuation and increase the malt profile of a beer. The only problem is that with a 1.081 SG there is already going to be a huge malt profile to start. 60% AA is pretty much to be expected on a 156 mash.

Mash temp might not be the only culprit here. I just kegged a batch of BM's Outer Limits IPA which I mashed at 160. My FG came in at 1.017, so don't be so quick to single out mash.

Then again, I did use US-05 which is always a monster attenuator.

Yeah, the Scottish Ale yeast I used (forgot to mention that rather important detail) isn't supposed to be a great attenuator. 69-72%, per the wyeast website. I knew I was mashing high, so I was hoping for the lower end of that range.

Even 67-68% would be understandable... but 63%? All because of a couple degrees in the mash? I do wonder if there's something else to blame here in addition to a high mash temp. Then again, it's possible my thermometers are lying to me and I was actually mashing higher that that even. Time for a little equipment testing.

I've got time before I plan on drinking this one, so I'll probably give it another shot of dry yeast in the meantime.

I think I'll go with the US-05 as well. Strong attenuator and clean profile is what I need.