My NB Black IPA was one day into vigorous fermentation in a temp controlled cooler, when the sensor fell out of the fridge, causing the temp to drop from 68 to 42. Fermentation stopped. Now that the sensor is back in the fridge, as the temperature returns to 68, should I expect fermentation to restart? What steps should I take to save my beer?
Yikes. #1 How long was the interim period estimation that you think it was sub 60f and now back up to >60f?
#2 You can try to rouse the yeast cake up into suspension with a bit of careful agitation of the carboy/ bucket etc…as the yeast have all but flocculated out of suspension with that cold of a temp and are sitting in a nice tight cake on the bottom now.
#3 If you test the SG and have fermented less than 20-30% studies have shown it is safe to introduce fresh O2 to kick start the roused yeast as cells require an abundance of O2 when growing now again and you do not risk too much incident of oxidation of post ferment wort per the studies I have seen on stuck ferment tactics etc…if adhering to a less than 30% fermented etc…
If the yeast saw the temp for many, many, many days you will stunt over 50% and have a chance of a great percentage reviving, as extreme heat would be the only thing to BAM kill all cells but you may have an overly sluggish/ stressed more incident of petit mutants or low cell count restarting and it will take days for it to regain steam ferment situation now. If you dont see renewed enthusiastic ferm within 24hrs definitely pitch a new slurry, sachet of dry etc…
ITsPossible, I appreciate your response and sharing of your knowledge. The fermentation was so strong that it clogged and blew off the bubbler. Fermentation lasted about 24 to 36 hours and it’s been in the 40’s for 36 to 48 hours.
So, you are suggesting a stirred but not shaken approach to reviving the yeast?
How about pitching US-05 dry yeast?
Yeah 1-2 days at that temp might not be as big a deal as we are thinking as the entire contents may not have chilled down past 50 during that period. Although do try to rouse or reintroduce the yeast back into suspension just in case they went mad and floc’ed out on yah.
24-36 You might have reached 50% fermentation towards terminal its hard to tell without a true SG reading. If you dont want to test SG/ or would sidetrack introduction of O2 at this time just leave the airlock on and rock er a bit to get them puppies up into suspension maybe even gently rock the vessel twice-three times in the next 24. If it is less than the 30% fermented mark you can remove the airlock and introduce pure/ pumped O2 or just shake er all to heck and you will reabsorb some O2 back into suspension that way. Be sanitary of course if you remove the airlock and just be aware that anything that will contaminate the beer will be airborne such as dust etc… so just dont run a dust mop around before you open the airlock and give er ell.
You have some percentage of ethanol in the brew already so that will help stave off chances of contamination also before the yeast fire back up. Which also brings up a valid flip of the coin as well.
Once you have higher and higher concentrations of ethanol in a stuck ferment such as this you create another hostile environment for the wacked out yeasties again this level all depends on your current SG. So as mentioned before if they aren’t going gangbusters in 24 from the above comment/ method, sure hit er with a sachet of 1056 as the neutral character of that strain makes it perfect for this type of situation.
Thanks bro. Will do and will post an update in a couple days. Once again, appreciate the help!
Sounds excellent, updates always help the entire community find answers to questions with short searches that way.
