Once I make a bottle of milk for my baby, I leave 3 oz of boiling water in a sterilised bottle on the side. Then when he is due a feed I add boiling 3oz to the 3oz of cooled boiled water bottle and then the 6oz of powder. Obviously shake it then it's ready to give him. It saves so much time BUT is this a good way? Will this sterilise the milk? It's the same as waiting 30 minutes for the kettle to cool down right? The water isn't TO hot etc. advice would be appreciated. I'm also from the uk. We have to use boiled water to sterilise the formula powder.