At night my one month old will start to stir at 3 hours So I go get a bottle from the fridge to start warming in anticipation that she will be up soon. I hate waiting until she is crying to feed her. but I end up laying back down to wait for it to warm or for her to fully wake up. past couple of nights she will sleep for at least another hour and clearly I have fallen asleep too. how long do you leave a bottle in a warmer? it is never too hot for her, and she hates cold milk but I don't want the formula to sour!