M84 yeast has gone to sleep...

[SteBeardface]

Hi guys, got a stuck fermentation by the looks of things. I made the Bohemian Pilsner from Greg Hughes' book but decided to use a starter of M84 instead of his recommendation of White labs. Everything seemed to go well at the start and after nearly 2 weeks and 2 24 readings, I'm stuck at 1.020 @ 15C (1.019 @ 20C), aiming for 1.014 @ 20C. I warmed to 15C about 3-4 days ago to speed things up a little, but it doesn't seem to have done the job.

I've read that it might be best to pitch a fresh starter aka do a krausening to finish things off, but not sure if this is best when it's about 5 points from finishing? Would it be worth just warming it up some more?

 

[Clint]

Just wondering has it completely stalked or going at a crawl...I've had some brews take a couple of weeks to drop just a couple of points.
What's the highest temp rating for your yeast? I think I'd put it up another couple of degrees and give it a thrashing ..

 

[SteBeardface]

It might be crawling, but I couldn't tell you until the end of next week :P

highest temp they give is 15C, so I'm reluctant to go higher BUT with 5 points left to go, a couple degrees might not cause any issues...

If need be, this thing can wait until after Christmas to be bottled, I'm sure nothing will go wrong with it in that time, provided I stop opening the lid!

 

[GerritT]

I think most of fermentation has been done, warming it a bit and giving it a quiet rinse with a sanitised spoon?

 

[An Ankoù]

I've used M84 and found it very attenuative, even at temperatures much lower than 15C. I've got a couple of last yeast bottles left and I have to ease the caps open a bit before taking them off. I think I bottled at 1006.
What was your mash temperature?
If your FG is 1020 then it should taste sweet. Does it? If not, I would suspect the hydrometer.

 

[SteBeardface]

I see, very attenuative then! I mashed at 65C for 1 hour using an all in one system, then mashed out at 77C for 10 mins before sparging. I do wonder if I should have left it longer in the mash...? I haven't tasted it, I'll have a nip later on. The hydrometer should be ok though, it's been accurate for all previous brews and nothing on or in it has broken? The wife just got me a TILT so I might chuck that in too, see what it says

 

[An Ankoù]

I see, very attenuative then! I mashed at 65C for 1 hour using an all in one system, then mashed out at 77C for 10 mins before sparging. I do wonder if I should have left it longer in the mash...? I haven't tasted it, I'll have a nip later on. The hydrometer should be ok though, it's been accurate for all previous brews and nothing on or in it has broken? The wife just got me a TILT so I might chuck that in too, see what it says

65C for an hour should be fine. I'm at a loss, frankly. Let us know how it tastes later on.

 

[SteBeardface]

Ok, so I decided to throw the TILT after giving it a steady light stir (think I nailed it, barely any oxygen in there, hopefully...) and chucked the TILT in afterwards. Left things to settle for a day, TILT read 1.018, which is probably about the same as my hydrometer. I decided to warm the brew fridge up to 18C, TILT read 16.7C after 24 h, but saw a 2 point drop to 1.016. I've knocked it up another 1C to 19C now and will check this when I get home tonight.

I think it's pretty much done, I'm not too bothered about the FG since it's so close now. Just need the diacetyl rest and I'll get it bottled this weekend!

Cheers for your help, guys! I'll do a quick update when I taste it at bottling time :)

 

[SteBeardface]

Final update - turns out the hydrometer that read 1.020 still read 1.020 after the stir and TILT showing it decrease to just past target FG at 1.012, confirmed by my other hydrometer.

The beer tasted lovely at bottling time, just need to be patient now... 3 months conditioning feels too long right now :-P very happy with this yeast so far. The TILT did it's job well, we'll see how it copes with my next brew - a Russian Imperial stout :-)