Stuck fermentation I need advice please

[NotaBrewMaster]

Stuck fermentation:


Hey all, I brewed a galaxy SMASH pale ale on 04/07/19 and think I might have a stuck fermentation. Some basic facts for context: 11 lbs of 2row, 7.5 Gallons of water, BIAB, mashed at 165 deg F for about 90 mins. 60 min boil used only galaxy hops and after cooling I wound up with about 6 gallons of wort with an OG of 1.050. I transferred to a PET Big mouth bubbler and stirred vigorously to aerate then sprinkled a single packet of safeale US-05 and stashed in my basement temp controlled fridge at a steady 65 deg F. I checked the FG on 04/19 and 04/22 and read 1.020 both times with a hydrometer. My target FG is around 1.012 according to brewers friend. As for the taste it’s not bad and I think the 60 ibus hides some of the sweetness but ideally I want to be closer to my target FG. Should I repitch? warm it up? bottle it? Be more patient? Thanks for the advice!

 

[kh54s10]

Was the 165 your strike temperature or your actual mash temperature? If it was your mash temperature you were WAY to warm and could have a lot of unfermentable sugars there. So, 1.020 might be as low as it will go. I would have mashed that at no more than 152, probably 148 or 150. I would warm it up to about 70 - 72 degrees and give it another week. If no change you could bottle it if it tastes OK. If not you might try some drastic measures to lower the gravity. Others will have to chime in on those techniques. I don't know them.

 

[NotaBrewMaster]

I should’ve clarified, 165 was my strike temp. Still too high?

 

[kh54s10]

Probably not, do you know what the mash temperature was? Puzzled! I don't see anything alarming that would lead to the stuck fermentation. I would raise the temperature and wait a week. Then maybe a re-pitch. I have never had US-05 stall.

 

[NotaBrewMaster]

Ok thanks. If it comes down to repitching any tips? Sprinkle, rehydrate or is a starter necessary? I don’t have any dme on hand to make a starter.

 

[RM-MN]

I should’ve clarified, 165 was my strike temp. Still too high?

Yes your strike temp was too high. I normally only see a few degree drop when I add the grains and I'm not using the full volume of water as I always sparge. I suspect your are at final gravity on this one.

 

[bobeer]

FWIW: Plugging some data (some assumed data) into my strike temp calculator... 11 lbs grain x 1.25 qt/lb with the grain at 70 degrees F should give you mash of 152 which is within the usual mash temps. The strike water volume for non BIAB is 3.44 gallons but I know BIAB does a full volume mash.

 

[kh54s10]

Yes your strike temp was too high. I normally only see a few degree drop when I add the grains and I'm not using the full volume of water as I always sparge. I suspect your are at final gravity on this one.

Not necessarily, It depends on the temperature of the grain, the amount of grain and your target mash temperature. In the winter when I lived in RI, I would often have to be at 168 -170 to get above 150 for a mash temperature..

 

[bobeer]

Been thinking about this... The only thing about the mash is with the 7.5 gallons of mash water it could still have been too hot for the 11 lbs of grain to cool down to an acceptable mash temp.

 

[NotaBrewMaster]

I’d love to say I was more careful and took the temperature before and after introducing the grain, independent of my kettle thermometer. I haven’t brewed in about six months and figured I was doing a simple batch so I got lazy with the process. It’s starting to seem to me that I’m at my final gravity and I’ll bottle and hope for the best. Knowing these sugars are not fermentable will they affect bottling?

 

[Gnomebrewer]

Was it full volume/no sparge? If so, you were almost certainly mashing very high and the ferment is finished. The sugars that are left aren't fermentable by that yeast.

 

[NotaBrewMaster]

Yeah it was full volume no sparge. When you say that yeast won’t ferment the sugars, is there a yeast strain that will?

 

[Gnomebrewer]

Yes, any strain of Saccharomyces cerevesiae var. diastatics and strains of Brettanomyces can ferment some dextrins and starch. But I wouldn't recommend adding either - leave your beer as it is. If it tastes a bit too sweet, add some 'hop tea'. If you want more booze, add some table sugar and/or DME.