That is not advised ! The water has to b hot 2 kill any bugs in the powder milk .
U can keep cooled boiled water to add to fresh boiled water to cool the bottle to a good temp to add the powder, then cool further to feed baby .
Your supposed to make fresh all the time but I found this near impossible! In the books I had it advised that if you were not able to make fresh feeds e.g u were going out for the day or baby went to childminders ect u should make the bottle as directed on the tin , then they needed to b cooled as fast as possible at the back of the fridge , use a cool bag for transporting ( I didn't ) put in fridge if 1 available and heat as required but only once. If u have a fresh made bottle and it cools u can reheat within a reasonable time, if its cooled down enough that baby won't have it so effectively this is what ur doing.
My son is 3 and as we all know the advice changes all the time but this method works best for me and aswell as breastfeeding in the 1st few week I will use this method again.
I know people that put the powder in cooled boiled water then heat to temp to feed baby! To me this method is not killing any bugs that could be in the milk!
I know people that have the powder in tubs separate and take out boiling water so that in effect when the baby's ready the water is the right temp for milk but it might not b hot enough.
The way I did it the thought is that the cooling and heating can cause bugs , but as far as I can tell this is generally the way it's been done for years and if done right shouldn't cause a problem , this is my opinion and as I said worked for me and I will do it again.
I know people that follow no guidelines at all, don't sterilise bottles on a reg basis and feed then milk that has been left at room temperature 4 hrs! I strongly wouldn't advise this but the kids seem no worse for it.
You will b given advice by health professionals, ask them the best method if fresh isn't possible . some will b very strict and not go off the book ! others ( who generally have kids ) will b more realistic and give practical advice and tips.
Work out what's best for you and ur baby, follow ur instincts.