Has anyone ever let their wort cool at a slower rate, say let it cool over night and pitch yeast in the morning? Is there any adv/disadv to a solow vs. fast cooling rate? How does cooling rate effect flavors?
When your wort is finished with the boil it is at boiling temperature. That should have killed off all the nasties that could infect your beer and they won't be able to survive until it cools. Turn off the burner and put a lid on it. The steam that condenses on the lid will sterilize the lid and kill off anything in the air between the wort and the lid. There is little chance of bacteria sneaking in past that lid in sufficient quantity to give your yeast any trouble if you pitch in the morning and get the yeast going. The yeast will simply overwhelm any bacteria and will soon produce alcohol that will also give the bacteria a hard time. Yes there is a risk of infection but a very small one.