Need Help! Did a temp drop kill my yeast?

[JPKDetroit]

I brewed a partial mash G L Christmas Ale clone on friday night at a buddies house. Everything went according to plan. OG was spot on. The fermentor was bubbling away for the past three days until the temp in his house dropped below 60 today. Did we kill our brew? Another buddy suggested taking another hydrometer reading to get an idea how close we got to the final gravity. Has anyone ever tried repitching some yeast? Am I looking at a short time frame to attempt a fix? Any help is appreciated.

 

[johnnybrew]

I wouldn't worry. Warm it back up and see if the activity picks up again. Chances are the majority of fermentation has already occurred. But, help us with a few questions:

What yeast did you use?
What was the OG?
What temp were you at before it dropped below 60F?
What was the activity like over the three days.... did it already peak and start to slow down?

You can always open it up and grab a sample for a reading, but I would recommend reducing the number of times you go into the beer to reduce the risk of contamination. Wait and see first. If you really did thermally shock them, they only went dormant. If there's more sugar in there and you warm them back up, they will start back up again. If not, you can also always pitch some dry yeast.

RDWHAHB.

 

[JPKDetroit]

Also...I stopped by after work to take a look. It didn't have the foamy head that I usually see in my bucket or carboy so I am pretty sure the yeast activity has stopped.

 

[Vendrixfly]

As far as I know a drop in temp cannot and will not "kill" yeast. They may go into a dormant phase at lower temperatures (refrig temp) or even slow to the point of no noticeable activity under certain cooler conditions, but to kill yeast the temperature must be very high, not low. I'd suggest moving the fermenter into a warmer temperature for a few days to see if any activity starts back up. You can even give the wort a gentle stir to get some of the yeast that may have settled back into the mix.

What kind of yeast did you use? I ask cause I just had a crazy-fast fermentation using Safale S-04 where the activity in the first 3 days was so intense that the days following seemed to appear rather inactive. Some yeast just works fast. Also, just because there is no activity in the airlock doesn't mean that fermentation has stopped.. it just may be in the end stages. You're beer is fine. Warm her up and giver her a stir or two and I bet it'll start right back up!

 

[JPKDetroit]

Thanks for the feedback. We moved it to a warmer part of his house. I believe the temp was around 62 the first three days. I cant really say if the bubbling was slowing down because my buddy has never brewed before so has nothing to compare it to. It sounds like it was pretty active those first three days. OG was 1.06

 

[JPKDetroit]

Thanks guys. Yeast was US 105

 

[Vendrixfly]

Thanks guys. Yeast was US 105

US-105, or Fermentis US-05? Ive never heard of or had experience with the former...

 

[JPKDetroit]

Sorry. US 05

 

[Vendrixfly]

Sorry. US 05

Good news That's a great dry yeast. If it was viable at pitching it should start right back up again. It's also a fast working yeast. I'd keep it in temps around low-mid 60's for the rest of the week, then move it to the upper 60's for 1-2 more weeks to let it fully attenuate and clean up. Some say because it's such a clean strain letting it get into the low 70's is okay too, but only for the last week or so in primary. If after this week there's still no activity in the airlock you should take a quick hydro reading to see where it's at, but I'd still leave it for 2 more weeks at slightly warmer temps. Hope it all goes well!

 

[postal_penguin]

If after warming it up you don't see any activity, try gently shaking or with a well sanitized spoon stirring up the yeast to get them back into suspension.

 

[beergolf]

You will be fine.

Think about it....How is liquid yeast stored? in the fridge. If cold killed yeast then all the liquid yeast packs stored in the fridge would be dead.

Just warm up your fermenter and it wil be fine. US-05 is a very hard working yeast and it will do the job.

 

[JPKDetroit]

Good news That's a great dry yeast. If it was viable at pitching it should start right back up again. It's also a fast working yeast. I'd keep it in temps around low-mid 60's for the rest of the week, then move it to the upper 60's for 1-2 more weeks to let it fully attenuate and clean up. Some say because it's such a clean strain letting it get into the low 70's is okay too, but only for the last week or so in primary. If after this week there's still no activity in the airlock you should take a quick hydro reading to see where it's at, but I'd still leave it for 2 more weeks at slightly warmer temps. Hope it all goes well!

Thanks V! You seem to know your yeast. My friend reported that airlock activity picked up a little this morning after we moved it to a warmer part of the house last night. I don't think upper 60's will be an option b/c we live in Michigan and heating a house to that temp can get expensive pretty quickly. I thought about asking him to move it near a heat register but I'm afraid that would result in a constant heating/cooling. I instead opted to put it as close to the thermostat as possible with the assumption that part of the house maintains the most consistent temperature. I also wrapped it in a blanket. From everyone’s (much appreciated) feedback it sounds like the brew should be alright. Thanks for the reassurance. I’ll try to remember to let everyone know how it turns out in a few weeks.

 

[Vendrixfly]

Good to hear she's dancin' for ya again! I think you made smart moves. The beer will be fine where its at, but if you want to get the most attenuation a brew belt around the fermenter isn't a bad idea either. Don't know whereabouts in MI you are but I'm sure there's a LHBS near you. Hopman's is a nice one in the Waterford area...bought my first keg from them.

 

[JPKDetroit]

Good to hear she's dancin' for ya again! I think you made smart moves. The beer will be fine where its at, but if you want to get the most attenuation a brew belt around the fermenter isn't a bad idea either. Don't know whereabouts in MI you are but I'm sure there's a LHBS near you. Hopman's is a nice one in the Waterford area...bought my first keg from them.

I hadn't heard of a brew belt but just looked them up online. Looks like a nifty little device and less expensive than I would have guessed. Have you used these with success? Are you able to set a specific temp on there or do u just monitor and adjust as needed?

 

[johnnybrew]

I hadn't heard of a brew belt but just looked them up online.... Are you able to set a specific temp on there or do u just monitor and adjust as needed?

JPK - along with the brew belt, there are other options that range from low tech to higher tech. For example, in the colder months I have put my carboys in a recirculating water bath (think of a plastic keg tub with small hobby pump moving the water around) that is heated by an aquarium heater. I like this because the distribution of the warmed water is 100% even around the carboy. The heater has a setting and I monitor the temp via a digital meat thermometer. I usually dial it in about 2 degrees lower than my target ferm temp because the internal temp of the carboy is typically warmer during active fermentation. As fermentation slows down, I move the temp up.

I also have a small fridge and Johnson control that I use in the warm months to keep the temps down. I have been thinking about replacing my water bath approach with the More Beer ferm wrap because of the drawback of having to mess with a large volume of water with the water bath rig. I would be able to control the temp of the ferm wrap using my Johnson control and keep everything in the (turned off) fridge to contain the heat. This would be easier in my eyes - just need to pull the trigger. And, I like the ferm wrap design over the brew belt because the product offers greater surface area and more even heat distribution.

I've read that some guys use heating pads that are intended to keep lizard cages warm! Obviously, there's lots of options!

Whatever approach you use, employing a system to control fermentation temperature is a great addition to your brewery. When you reduce the variability of temperature you will then control yeast health and output - which will translate into better beer.

Brew on. JB