Question about temperature variations

[JonnyO]

I brewed a batch of amber ale this weekend (Saturday), pitched the yeast around 78 degrees. Sunday morning the temp. was around 68 and fermentation had started nicely. Sunday night temp was around 66, and this morning, down to around 64. I don't think it will get too much cooler than that, and I'm trying to bring it back up a bit. My question is, are temperature fluctuations like this detrimental to the fermentation process. I seems like my airlock action has slowed as the temp as dropped. I know fermenting at too high a temp can cause problems, but is my beer in any trouble by the lower temperatures? Living in Mobile, AL low temps. have never been a problem, so I'm curious.

 

[TheJadedDog]

In general you want to keep the temperature as stable as possible; I try not to let mine fluctuate by more than a few degrees. Keep in mind, the act of fermentation itself will raise the temp a degree or two.

I ferment all my beers at 65 degrees and I have never had a stuck ferment due to the temp being too low so I think you'll be okay at 64.

 

[brewhead]

here's a trick i've learned that will help stabalize your temps shy of a dedicated temp controlled fridge or apparatus.

take your cboy - place it in a tub of room temperature water. drop your thermometer in there assuming you have a glass floaty type. the water will stabalize the temperature influctions since given enough mass, water will not gain or release energy quickly. keep an eye on your thermometer to check.

my conditions are a bit more extreme since my brew barn is un conditioned so i use the same tub of water but i regulate the temperature with two large aquarium heaters in the winter and 2 litre bottles of ice in the summer. works like a charm.

 

[hagbardceline]

So just to clarify unstable temps can result in a stuck fermentation?

I have been putting my carboy in a big plastic rubbermaid storage container and filling with water. Due to the summer temp I have been putting a 3/4 full frozen gallon of water in twice a day.

Once I put that in it drops the temp 5 degrees or so but over the day it raises the temp back up to the low 70s. Am I better off just leaving it in the low 70s instead of the temp swings?

 

[malkore]

So just to clarify unstable temps can result in a stuck fermentation?

I have been putting my carboy in a big plastic rubbermaid storage container and filling with water. Due to the summer temp I have been putting a 3/4 full frozen gallon of water in twice a day.

Once I put that in it drops the temp 5 degrees or so but over the day it raises the temp back up to the low 70s. Am I better off just leaving it in the low 70s instead of the temp swings?

5 degress is ok. 10 degree temp swings will stress the yeast. more likely to cause off flavors than a stuck ferment unless it swings too cold.

 

[BarleyWater]

You would be best off not letting it rise up that much. Try keeping it stable in the 60's for at least the first few days, then you could probably just leave it alone until it finishes up because the yeast will have already produced the majority of what they are going to.