Stalled Old Ale help

[technobabble66]

Howdy, I have a minor dilema
I’ve brewed an Theakston’s Peculier-like Old Ale clone, which has finished a bit high.
OG= 1.064
FG= 1.024 - which is ~60% attenuation, and as you can probably guess, is a bit too sweet - it needs to lose between 6-8 more SG points.
Mash-wise, I did a main sacch step at 68°C for 60mins.
I fermented with 2 packets of MJ Dark Ale (into 25L).
After an amazingly fast ferment - hit close to current FG within 30hrs - i accidentally let it drop to 16°C overnight on the 3rd night and it stalled shortly thereafter. I’ve tried a fast-ferment test (at ~25-30°C) and it seems to settle at roughly the same point: ~1.022-4.

So my problem is whether i bottle as is or try to do something to drop the SG a bit more.
I’m inclined to do the latter as it still tastes a little too sweet to me.

I’ve tried to keep it at higher temps (~22-23°C) for 5 or so days.
I haven’t tried stirring it, as the FF test seemed to indicate even if the yeast is roused, it’s still only going to drop it another point or 2.

So i’m kinda wondering if i need to throw in a second yeast.
If i do, which particular yeast should i go with, and how to do it?
I’ve got a few yeasts, liquid and dry, that i could use. The obvious choice would probably be MJ M10 Workhorse, as it should be up to the task by it’s reported robust nature. However, i’ve then got another reservation as to whether this yeast might drop the SG too far.
Ideally i want to hit FG=1.018, though 1.016 would probably be fine also.
Should i also prepare a starter for whichever yeast i go with, or just rehydrate and throw it in?

Help eagerly sought, as it’s tying up my FV fridge!

 

[sponge]

Any chance you can add some sugar to kickstart the yeast a bit?

 

[technobabble66]

Yep, can.
Is it likely to help, though?
It's my first time using MJ M03 Dark Ale, and it sounds like it generally finishes high.
Easy to do if you think there's a good chance it'll do the trick.

 

[sponge]

Hmmm.. Just having another read through, if you'd tried a FF then the sugar might not actually do too much.

Have you made sure the hydrometer reads 1.000 in water at room temp? Although it still tastes sweet so that might not help either.. How old was the yeast and has it been stored in a fridge, etc?

 

[manticle]

Try another fast ferment test but this time use some fresh yeast in an active starter. You could try with the same yeast strain or finish with another appropriate type that is known for a drier finish.

Active starter though - don't just add the yeast to the stalled ferment.

Have you tried usual rousing tricks - swirl, raise temp, rack to different fermenter? I'd guess if the fast ferment is giving the same result that the yeast used has done all it can but worth a try.

 

[fcmcg]

champagne yeast can also be worth a try..same deal though...hydrate first

 

[technobabble66]

Try another fast ferment test but this time use some fresh yeast in an active starter. You could try with the same yeast strain or finish with another appropriate type that is known for a drier finish.

Active starter though - don't just add the yeast to the stalled ferment.

Have you tried usual rousing tricks - swirl, raise temp, rack to different fermenter? I'd guess if the fast ferment is giving the same result that the yeast used has done all it can but worth a try.

About to start up some generic yeast from a kit - i assume they're fairly robust - to try another FF test.
So i'll make up a 200mL starter with 1/3rd of a packet, rev it up for 24 hrs, then introduce the TOP clone beer to it and see if it can go lower. Just gotta remember to re-check the SG at the start of fermentation (calibrate for dilution).
I'd use the M10 Workhorse in the FF test, but i won't be using it for anything else in the immediate future if i don't end up using it in this; so i don't think there's much point opening it just yet.

champagne yeast can also be worth a try..same deal though...hydrate first

I would, but i hate the champagne finish - though i've only tried it in cider, not in ales. I'll see how the FF test using kit yeast goes, then probably use the M10 if it looks like it will drop further

 

[technobabble66]

A quick update:
I faffed around for a while getting a mini-starter going to then do a FF test using left-over dried kit yeast. This seemed to drop the SG a few points - down to maybe SG=1.018-20.
So i then prep'd a large starter of the same kit yeast, only to discover as i put it into my FV fridge overnight to fire up, that there seemed to be some kind of krausen activity on the top of the FV again - basically some froth over 30% of the top. It looked like the original yeast may've been kicking back into activity. So i checked the SG this morning - it's down to ~SG=1.016-7 !!
That's ~75% attenuation, for the record.
Buggered if i know what happened - i can only assume that the little drop in temp on the 3rd or 4th day stalled the yeast. It's now been sitting ~20°C for the last 3 weeks, aside from another slow drop to 17°C over 4 days about 1 week after the initial stalling. So at some point recently, it's decided to wake up again. Fwiw, no stirring occurred, so it's either time or temp that must've been the key to it waking up.

 

[technobabble66]

As i posted in the MJ Craft series yeasts just now:

"Final update:
It continued to ferment out to FG=1.012. After the yeast had fired back up again, i kept the temp ~20-22°C and the yeast happily continued munching away.
Which for the Old Ale recipe is annoyingly several points below where it needed to finish.
To try to cater for these results in my recipe spreadsheet (thanks ianh !) i nominated 75% attenuation and dropped the mash temp down to 63°C. This hit all the figures i'd achieved with this brew.
I went the option of manipulating the mash temp because i have doubts that the MJ Dark Ale would attenuate much more than that - time will tell with other people's results.
Also, the mashing process i did basically went all to plan (55/67/72/78 for 5/60/20/2) up to the post-mashout recirculation. I hit 78°C for 2 mins, then pulled the bag, dropped it into a 2nd vessel and started up a recirculation for 20mins, as is part of my normal process. However, i then had to suddenly go to work for 3 hrs, so had to stop it there and just let it sit until i could return home, at which point i heated it back up to ~78°C, finished the recirculation and sparge and did the boil, etc.
I'd assumed the time at 78°C (2-10mins?) had denatured the relevant enzymes, however given how low it's attenuated, i can only think that the amylases have continued working for a while.
Just thought i'd post this anecdote partly for those who accidentally hit high 70's for a minute or 2 in their mash as reassurance that some enzymes seem to survive for a little while."