temperature swing???

[David20Hersch]

two days ago i brewed a hefeweizen and put my stc on 65f with a differential of 2 degrees. today i really wanted to lower the temp after reading a bit more so i did and now its at 63 with a differential of 2 degrees. will this hurt the beer???

 

[flars]

During active fermentation the lower temperature will probably not have an effect on the yeast and attenuation. A temp swing like this when fermentation is near the end may cause the remaining yeast in suspension to drop out sooner.

 

[Gavin C]

If the hysteresis is set at 2F your getting that sort of swing anyway.

Why not reduce the hysteresis to the minimum and the delay to the maximum.

I use 0.3C and 10 mins with the probe measuring the wort temperature at all times. It never leaves the set point +/- 0.3C

 

[h22lude]

I agree with Gavin. Setting it up that way will give you less of a swing. Not that 2° either way is that much but when you get to the higher end of the range or the lower end, it may push you over.

To answer your question, no going from 65 to 63 won't affect the beer. Depending on the yeast strain, the height of fermentation may be coming down after 2 days so lower the temp may do nothing. When it starts getting closer to the end of fermentation, it may be better to raise the temp a few degrees to keep the yeast working and cleaning up. Won't hurt either way though.