2 weeks ago I started an oktoberfest brew. The primary fermenting seemed to go well, I started it around 4pm and made sure to wake up in the middle of the night to make sure that I got it into the garage as soon as I noticed the fermentation begining. I put my carboy in a fridge that was/is not plugged in not taking into consideration that fermenting produces heat. When I woke up in the morning the temperature was a perfect 50-52f, when I got home around 6pm the temp was up to 64f, I hauled ass to the store and bought ice to cool it down as fast as I could and just left the carboy in the open in the garage and the tempurature was perfect.
After 11 days I siphoned to my secondary, it tasted good as far as I was concerned. My og was 1.060 when I measured the gravity it was 1.041~. Now my concern now is that thursday the temperature went from about 40f in the morning to about 85f and my brew was at 62f AGAIN! So I hauled ass to the store again and tossed a couple bags of ice and my secondary into the unplugged fridge again. The temperature is once again a perfect 50f-52f but for the past couple of days I have not noticed any bubbles in my airlock and my brewing instructions say that it should take up to 5 weeks for the fermentation to complete.
Have I managed to screw up my oktoberfest? Are lagers so tempermental that any temperature change will kill the yeast or cause off flavors?
The oktoberfest is my 3rd batch and I am afraid maybe I got a little presumptuous