Hi I start my first homebrew last Sunday it is now Wednesday fermentation started about 8 hours after pitching the yeast on Sunday the yeast came with the brew extract kit under the lid I pitch the yeast around 76degrees and since Sunday the wort has cooled down and the temp fluctuates between 61 degrees and 70degrees is this a problem with the temp going up and down over the past few days? Since the airlock started bubble it hasn't become more or less active just stayin the same consistent bubbles...the brand of the malt extract I used was Doric Canadian beer mix..... Iv noticed a fruity banana type smell coming from the air lock too is this a problem?