1.047 - 1.014: Yeast stressed out?

Hello,

I'm currently doing an English bitter. The OG was 1.047 which gave me a partial mash efficiency of about 75% I think. I reused a Gervin Ale yeast harvested on the day of pitching new brew. Used about 150ml washed from the slurry. It's been sitting between 62 and 68f for 2 weeks and is only at 1.014. The last brew I did with this yeast (fresh from pack) got down to about 1.007. This brew at 1.014 tastes a little sweet which leads me to believe the yeast might have bonked out due to me not pitching enough or something? Any ideas?
Maybe it just needs another 2 weeks? Would have thought those temps were ideal.

Either way, I'm not too bothered, just curious as to what you might think? I'm going to test it again after another week and probably give it an additional week on top of that. I've ordered a fresh pack of Gervin Yeast in case you think I should pitch some more, i.e. if the yeast in there has possibly stressed out.

 

If it was at 68 early and then dropped to 62, that could have caused the yeast to drop out. If you have a way to warm it up and hold it at 68, that may help reactivate them to finish it off. At this point, their growth phase is well over, so if your only option is going a little warmer than that, then you should still be ok.

You'd have to include your full recipe to judge if there's something in that which may have limited the possible FG. You're at 70% apparent attenuation, and by recipe you could have hindered it by the 3-5 gravity points which it takes to be 75-80%.

 

23 litre Recipe (mashed @ 154f):

2kg Irish Pale Malt
340gm Medium Crystal
110gm Dark Crystal
1.8kg lme

55gm Goldings, East Kent [5.7 %]
15gm Progress [6.60 %]

It sits at an average of 64-66f now I'd say, not sure how to warm this up... warm water bath? I've ordered an aquarium heater from China but it'll be weeks before I get it. Maybe I'll just hydrate the new pack of yeast when it comes, dump it in and hope for the best.

Edit: stuck the fermenter in a 95f 1 gallon water bath.

 

154 is relatively high, 10% crystal, and unknown fermentability of extract could mean you're done. I'd just let it sit bother week. You might get another point or two. But I'd go ahead and package then. The crystal malts will also add to the sweetness.

Another thought is how much you aerated or oxygenated at pitching. If that was missed, that could have stressed them. Don't aerate now though. I'm just looking for remedies for next time.

 

it doesn't just depend on the yeast, it depends on how many fermentable sugars you have in your wort, temperature, etc.

1.014 doesn't sound like too high of a final gravity for many worts/beers.

 

Is it possible that you didn't pitch enough? I would expect that you would receive a similar outcome provided there was enough yeast. If you have to bottle condition and it doesn't carb, than you have your answer. If you want it to ferment more and achieve a lower gravity, try adding more yeast.

 

Actually it was 67C which is about 152F. It was my understanding that this range produces a medium body. I like a bit of residual sweetness and mouth feel that comes from this range, maybe not appropriate for this style? Either way I mashed slightly higher than this during my last APA and got it down to 1.007.

I did aerate quite a bit. One thing I did notice though, no matter how much I stirred the crap out of it, I didn't get much of a froth, I usually get loads when aerating.

Probably is possible yep. But I tried to base my pitching rate on the mr malty website, which I think is a little ambiguous.. i.e. thick/thin slurry etc.

Cheers for the replies.. I've ramped up the temp to 68/69F over the last 2 days and it has come down to 1.012 so I'll keep it going for another week or two and see what happens. I've more yeast in the fridge now, but I don't think I need it tbh.

 

i had a similiar issue, when i pitched more yeast, i got mine down from 1.004. the sg was 1.070

 

You're at 71% attenuation; within the range expected of the strain.

 

Given the recipe and the mash temperature I would say that at most you might get one more point. I don't think you need to pitch any more yeast. Keep it warm for a few more days then take a reading. If it is still 1.012 I would say it's done.

 

Yep, a week later it's at 1.011. Raised the temperature a few degrees for a few days, not sure it helped much, couldn't have done it any harm anyways. Either way, going in the bottles tonight or tomorrow! Cheers guys.