When my wife and I first came home from the hospital we were in a delirious state, and while I had heard numerous ways to warm a baby bottle, I started to doubt my memory. I frantically called a few relatives and friends to get their perspective and tried a number of methods, but what worked best for us was using the microwave.
Warning – you do not, ever, put the bottle or contents of the bottle in the microwave.
What Works For Us:
The amount of time you place the bottle in the hot water will vary depending on the type of bottle, size, amount of liquid, and start temperature of formula/milk.
For best results, keep the mug over the sink while the bottle is warming and test the formula/milk a few times. You will end up spilling some water, hence the advice of testing of the sink.