Yeast Temp Fluctuation

[thisisbeer]

I understand a big swing in ferm temp can negatively affect the yeast. But was wondering what is considered a big swing in temperature? 2 degrees? 5 degrees? 10? I am just curious if the temp swing is only harmful if its out of optimum range or if it could be from bottom to top of optimum range very quickly. I have a thermowell in my wort that goes to a digital thermometer and another that just checks the ambient temp that is hooked up to the temp control that runs my freezer. It's confusing because I hear a lot of people worry about temp swings of the wort with the controller probe just hanging in the freezer. My ambient temp does have a few degrees swing in it but the wort never changes more than half to 1 a degree.

 

[BigFloyd]

If you can, you'd be better served having your temp controller hooked up to the sensor that reads the beer temp rather than the air. If you think about it, the only temp that matters is that of the fermenting beer. You'll also pretty much eliminate any significant temp swings, which not only have to do with the difference in degrees, but also the suddenness with which the swings occur.

 

[billpaustin]

I'm pretty new, but here are my thoughts. If you get outside the window of the yeast's preferred temperature, there could be a problem. Too cold, and the yeast goes to sleep. Too hot, and the yeast produces yucky stuff.

Within that range, 1-2 degrees swing is nothing, 4-6 degrees is probably nothing, and 10 degrees is getting to be something to think about.

 

[diS]

I think that everything under 10 degrees is not that harmful but the question is how often temperature fluctuate. eg. if you start with 60F and raise it till the end of fermentation to 70F it would be pretty normal, but if temperature swings by 10 deg every day it could leave negative effect on yeasts and flavor.