I suspect there is a very simple mathematical formula for preparing formula (forgive the pun) that simply mixes a combo of freshly boiled water and room-temp water.
To be specific, if I need to prepare an n mL feed, I would like to:
- Mix x mL room temp (r) water + y mL boiling water to get 70°C water
- Mix in the scoops of powder
- Mix in z mL of room temp water to bring it down to 45°C.
x + y + z should equal n. But I'm struggling to figure out what x, y and z are given r.
Infant formula requires initially mixing with water at 70°C to kill cronobacter, then bringing it to about 45°C so baby can drink it. Prep guidelines say to boil water, wait for 30 mins till it gets to approx 70°C, add the powder, then rinse the bottle under tap water until it reaches about 45°C. Very imprecise and inefficient with a screaming baby.
As this post says, the heat capacity of water stays almost constant between 0°C to 100°C, therefore (for example) you can mix 30% of 0°C water and 70% of 100°C water and you'll end up with a liquid that is at 70°C, up to a small error. So I'm hoping this kind of calculation could be applied to my problem, albeit with room temp (r) water instead of 0°C.
- The amount of water in the first step should be maximized so the powder can be adequately dissolved.
- Approximate results are ok, though we should err on the side of slightly higher than 70°C for the first step and slightly under 45°C for the third, if anything.
- Room temperature is a variable to account for different climates.
- I guess the addition of powder would cool the result down slightly, but as I mentioned, slightly under 45°C for the final result is ok.
My baby brain can't figure this out. Can anyone help? The goals is to create a spreadsheet so that I can simply look up all the required measurements for a quick and easy (and safe) midnight feed. You would be helping out a very stressed mum :)