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Infant feeding

Get advice and support with infant feeding from other users here.

I’m struggling to understand if I’m making baby formula correctly.

36 replies

BoyMumToBe34 · 13/01/2026 19:18

I use boiling hot water pour it into a thermos flask and overnight use it.
i pour the water into the bottle to measure it then into the nuby rapid cool, I add the powder and cool it using the rapid cool.

now I’m told the water can’t be too hot so the first bottle I make the water if practically just boiled when I add the powder, but a few feeds later the water in the flask will have cooled down. How am I meant to know exactly when it is 70 degrees unless I constantly have to boil the kettle, wait 30minutes during the night when I’m feeding baby every 2 hours and keeping him upright for 30-45minutes. I’m exhausted and it just feels too much. Please advise

OP posts:
Flaked · 13/01/2026 19:22

Do you have a HV?

How old is your baby? Are you alone?

basically boil and let it cool. Then fine to have for up to 4 hrs.

Icecreamandcoffee · 13/01/2026 19:28

I personally use the hot shot method. So depending on how big the feed is, you put 30ml boiling water in the bottle, add formula and swirl together. Then add the rest of the water for the feed from cooled boiled water and swirl together.

So for example: 120ml or 4oz feed, 30 ml hot boiling water from flask, then the other 90ml cooled boiling water.

I used 2 flasks for this so 1 thermos for the boiling water, boil kettle before bed and fill up and then another flask or even just a clean plastic tumbler with a lid of cooled boiled water. I bought myself a little pyrex jug that does ml to measure the water.

I use this one.

https://www.amazon.co.uk/Pyrex-250-Kitchen-Measure-Beaker/dp/B007ZQ45XA/ref=asc_df_B007ZQ45XA?mcid=92ef99ecbce631b9a617f733ffa7d2e1&tag=googshopuk-21&linkCode=df0&hvadid=696385493959&hvpos=&hvnetw=g&hvrand=6651973050861299263&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9046231&hvtargid=pla-421677703163&psc=1&hvocijid=6651973050861299263-B007ZQ45XA-&hvexpln=0&gad_source=1

I use the rapid cool for out and about and find that sometimes it makes the feed too warm so I always make the bottle about 15 mins before I need it to give it time to cool.

Amazon.co.uk

Amazon.co.uk

https://www.amazon.co.uk/Pyrex-250-Kitchen-Measure-Beaker/dp/B007ZQ45XA/ref=asc_df_B007ZQ45XA?gad_source=1&hvadid=696385493959&hvdev=m&hvexpln=0&hvlocphy=9046231&hvnetw=g&hvocijid=6651973050861299263-B007ZQ45XA-&hvrand=6651973050861299263&hvtargid=pla-421677703163&linkCode=df0&mcid=92ef99ecbce631b9a617f733ffa7d2e1&psc=1&tag=mumsnet&ascsubtag=mnforum-breast-and-bottle-feeding-5475290-im-struggling-to-understand-if-im-making-baby-formula-correctly

bongbingboo123 · 13/01/2026 19:31

Ahhh I remember the conundrum of this and feeling so tired I couldn't think!
I'd make the bottles up with half/ ish the water boiled from the kettle and let it cool... then took a thermos up to bed with me and topped it up to the right temperature for baby... you got this 💪

MarvellousMonsters · 13/01/2026 19:33

Flaked · 13/01/2026 19:22

Do you have a HV?

How old is your baby? Are you alone?

basically boil and let it cool. Then fine to have for up to 4 hrs.

Edited

“basically boil and let it cool. Then fine to have for up to 4 hrs.”

Actually no. Very much no. Powdered formula is not sterile, and needs to go into hot water to kill as much bacteria as possible. Boiling the water then letting it cool before putting the powder in doesn’t kill the bacteria and can cause gastroenteritis. Ready made formula is sterile, and just needs to be warmed or can be used at room temperature.

Step-by-step guide to preparing a formula feed
Step 1: Fill the kettle with at least 1 litre of fresh tap water (do not use water that has been boiled before).

Step 2: Boil the water. Then leave the water to cool for no more than 30 minutes, so that it remains at a temperature of at least 70°C.

Step 3: Clean and disinfect the surface you are going to use.

Step 4: It's important that you wash your hands.

Step 5: If you are using a cold-water steriliser, shake off any excess solution from the bottle and the teat, or rinse them with cooled boiled water from the kettle (not tap water).

Step 6: Stand the bottle on the cleaned, disinfected surface.

Step 7: Follow the manufacturer's instructions and pour the amount of water you need into the bottle. Double check that the water level is correct. Always put the water in the bottle first, while it is still hot, before adding the powdered formula.

Step 8: Loosely fill the scoop with formula powder, according to the manufacturer's instructions, then level it using either the flat edge of a clean, dry knife or the leveller provided. Different formulas come with different scoops. Make sure you only use the scoop that comes with the formula.

Step 9: Holding the edge of the teat, put it into the retaining ring, check it is secure, then screw the ring tightly onto the bottle. Make sure the ring is attached firmly.

Step 10: Cover the teat with the cap and shake the bottle until the powder is dissolved.

Step 11: It's important to cool the formula so it's not too hot to drink. Do this by holding the bottle (with the lid on) under cold running water.

Step 12: Test the temperature of the formula on the inside of your wrist before giving it to your baby. It should be body temperature, which means it should feel warm or cool, but not hot.

Step 13: If there is any made-up formula left in the bottle after a feed, throw it away.

https://www.nhs.uk/baby/breastfeeding-and-bottle-feeding/bottle-feeding/making-up-baby-formula/

nhs.uk

How to make up baby formula

How to make up formula milk feeds for your baby correctly and safely.

https://www.nhs.uk/baby/breastfeeding-and-bottle-feeding/bottle-feeding/making-up-baby-formula/

Icecreamandcoffee · 13/01/2026 19:40

If you are doing a lot of formula feeding (either exclusive formula feeding or combi feeding) I highly recommend a bottle prep machine (there are different brands at different price points). It takes all the maths out of it and bottles come out drinking temperature. It does the hot shot method but does all the measuring for you. It can be a lifesaver when you are making bottles every 2 or 3 hours of the day and night.

LifeOnNeptune · 13/01/2026 19:42

We used a tommee tippee bottle prep machine overnight.
To make bottles quickly, if you want to use fresh water, boil it and pour 30ml straight into a bottle. Let it cool to 70 degrees, which only takes a few minutes because it's such a small volume. Add the formula, mix it up and top up with cooled boiled water. Much quicker than letting a whole litre cool in a kettle!
We also had a nuby rapidcool and used the hotshot method for that too.

Sunshineclouds11 · 13/01/2026 19:42

I done the same as @Icecreamandcoffee

Flaked · 13/01/2026 19:44

MarvellousMonsters · 13/01/2026 19:33

“basically boil and let it cool. Then fine to have for up to 4 hrs.”

Actually no. Very much no. Powdered formula is not sterile, and needs to go into hot water to kill as much bacteria as possible. Boiling the water then letting it cool before putting the powder in doesn’t kill the bacteria and can cause gastroenteritis. Ready made formula is sterile, and just needs to be warmed or can be used at room temperature.

Step-by-step guide to preparing a formula feed
Step 1: Fill the kettle with at least 1 litre of fresh tap water (do not use water that has been boiled before).

Step 2: Boil the water. Then leave the water to cool for no more than 30 minutes, so that it remains at a temperature of at least 70°C.

Step 3: Clean and disinfect the surface you are going to use.

Step 4: It's important that you wash your hands.

Step 5: If you are using a cold-water steriliser, shake off any excess solution from the bottle and the teat, or rinse them with cooled boiled water from the kettle (not tap water).

Step 6: Stand the bottle on the cleaned, disinfected surface.

Step 7: Follow the manufacturer's instructions and pour the amount of water you need into the bottle. Double check that the water level is correct. Always put the water in the bottle first, while it is still hot, before adding the powdered formula.

Step 8: Loosely fill the scoop with formula powder, according to the manufacturer's instructions, then level it using either the flat edge of a clean, dry knife or the leveller provided. Different formulas come with different scoops. Make sure you only use the scoop that comes with the formula.

Step 9: Holding the edge of the teat, put it into the retaining ring, check it is secure, then screw the ring tightly onto the bottle. Make sure the ring is attached firmly.

Step 10: Cover the teat with the cap and shake the bottle until the powder is dissolved.

Step 11: It's important to cool the formula so it's not too hot to drink. Do this by holding the bottle (with the lid on) under cold running water.

Step 12: Test the temperature of the formula on the inside of your wrist before giving it to your baby. It should be body temperature, which means it should feel warm or cool, but not hot.

Step 13: If there is any made-up formula left in the bottle after a feed, throw it away.

https://www.nhs.uk/baby/breastfeeding-and-bottle-feeding/bottle-feeding/making-up-baby-formula/

You misunderstood as I wasn’t clearly

I mean boil and make it and then let it cool!

Icecreamandcoffee · 13/01/2026 19:44

I do the same as @LifeOnNeptune when I use the rapid cool too. Use the rapid cool to do the hot shot method.

Flaked · 13/01/2026 19:45

I was never uptight about it reaching 70 degrees. I’d boil, wait a a minute or two and then make

TimeToStopLurking · 13/01/2026 19:51

Icecreamandcoffee · 13/01/2026 19:28

I personally use the hot shot method. So depending on how big the feed is, you put 30ml boiling water in the bottle, add formula and swirl together. Then add the rest of the water for the feed from cooled boiled water and swirl together.

So for example: 120ml or 4oz feed, 30 ml hot boiling water from flask, then the other 90ml cooled boiling water.

I used 2 flasks for this so 1 thermos for the boiling water, boil kettle before bed and fill up and then another flask or even just a clean plastic tumbler with a lid of cooled boiled water. I bought myself a little pyrex jug that does ml to measure the water.

I use this one.

https://www.amazon.co.uk/Pyrex-250-Kitchen-Measure-Beaker/dp/B007ZQ45XA/ref=asc_df_B007ZQ45XA?mcid=92ef99ecbce631b9a617f733ffa7d2e1&tag=googshopuk-21&linkCode=df0&hvadid=696385493959&hvpos=&hvnetw=g&hvrand=6651973050861299263&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9046231&hvtargid=pla-421677703163&psc=1&hvocijid=6651973050861299263-B007ZQ45XA-&hvexpln=0&gad_source=1

I use the rapid cool for out and about and find that sometimes it makes the feed too warm so I always make the bottle about 15 mins before I need it to give it time to cool.

Exactly this method. Better still invest in a Tommee tippee prep machine which does this for you with two pushes of a button. Game changer.

sharkyroy · 13/01/2026 19:53

I used ready made for night feeds

FlibbertyGibbitt · 13/01/2026 19:54

DIL had a Tommy Tippee prep machine. It was fab, so different from when I made up bottles.

LavenderBlue19 · 13/01/2026 19:56

We had a prep machine, it was brilliant. I remember my head swirling with confusion when I tried to figure it all out on no sleep! I also had a meat thermometer to check the hot water temp when we went out (yay anxiety).

There are concerns about PP machines getting mouldy, but you just need to make sure you clean it regularly and use the official filters. Mine was absolutely fine after a year's use.

BoyMumToBe34 · 13/01/2026 19:58

@LavenderBlue19@sharkyroy can I ask what the cleaning was like for these machines? Isit complicated and how often please

OP posts:
RabbitsEatPancakes · 13/01/2026 20:06

To use thermos flasks correctly you need to fill with boiling water and close, leave for a few minutes and then tip away and fill with your hot liquid.

Equally to keep things cool you need to open the flask and put it in the freezer or fill with ice before filling with whatever you want to keep cold.

MarvellousMonsters · 13/01/2026 20:11

Flaked · 13/01/2026 19:44

You misunderstood as I wasn’t clearly

I mean boil and make it and then let it cool!

Ahh right, I see! It should be used immediately though, not stored for 4 hours.

LavenderBlue19 · 13/01/2026 20:11

BoyMumToBe34 · 13/01/2026 19:58

@LavenderBlue19@sharkyroy can I ask what the cleaning was like for these machines? Isit complicated and how often please

I had mine in 2019 so might be different now, but basically it was very easy - it flashes to tell you it needs cleaning, you follow the instructions in the booklet. As far as I recall you just run distilled water through on the cleaning programme. Take a few bits apart. It needed cleaning after X number of bottles made. I remember making my partner do the first one because I had zero brainpower. But it really wasn't hard.

TimeToStopLurking · 13/01/2026 20:13

BoyMumToBe34 · 13/01/2026 19:58

@LavenderBlue19@sharkyroy can I ask what the cleaning was like for these machines? Isit complicated and how often please

I treat it like a kettle. Top up with fresh water. And conpletely empty and refill regualarly. There's a boiling water flush-through cleaning setting. I do this every so often. Only issues I've had is that a handful of times it's dispensed the wrong amount of water. So for the second button push where it dispenses room temperature water, I put that in a separate bottle and tip into the first one. Has only happened a few times to be fair but it's annoying. Otherwise I love it

Iloveeverycat · 13/01/2026 20:17

Step 2: Boil the water. Then leave the water to cool for no more than 30 minutes, so that it remains at a temperature of at least 70°C.
You can buy kettles that go up to 70c

MarvellousMonsters · 13/01/2026 20:27

Iloveeverycat · 13/01/2026 20:17

Step 2: Boil the water. Then leave the water to cool for no more than 30 minutes, so that it remains at a temperature of at least 70°C.
You can buy kettles that go up to 70c

True, that would work.

PardonMe3 · 13/01/2026 20:42

You can get a variable temperature kettle.

IAmNotPrepared · 13/01/2026 21:10

Just FYI, the machines don’t actually always sterilise the powder. It’s a couple of years old but afaik it’s still the most up to date study into them. You should still check the temp if you use it

https://www.bbc.co.uk/news/uk-wales-67001503.amp

Baby being fed by mum

Baby formula machines not killing bacteria, study finds - BBC News

Parents are warned to check formula temperature as a study shows most machines do not kill bacteria.

https://www.bbc.co.uk/news/uk-wales-67001503.amp

lollylo · 13/01/2026 21:18

We got a perfect prep. Brilliant, always said I’d get one if I had to formula feed. When out, got a flask with a temperature gauge for hot shot - so I knew it was over 70 - and decanted cooled boiled water from the nuby to make up the feed. Baby was fine.

I am way too impatient to be boiling kettles and waiting 25 minutes for the ‘correct’ temperature- more risk it would be the wrong temperature in my view and I’d not want to leave a baby that long.

Devilsmommy · 13/01/2026 21:21

This is why I had a hot water dispenser set at 70 to take all the faff away