How to make formula milk in advance

Sometimes it may not be practical to make up fresh feeds for your baby each time they are needed. Here's how to prepare formula milk in advance for when you are going to be out.

How to make bottles of formula milk in advance
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Table of contents

Your health visitor will tell you to make up formula feeds fresh for every feed. This is fine if you are at home and you are able to time exactly when your newborn is going to be ready for his bottle.

This can take quite a lot of planning and a lot of screaming from your hungry baby if you are to get each feed ready at exactly the right time, especially in the middle of the night.

Also sometimes it is just not practical to make up feeds fresh every time, such as when you go out for the day or you have to leave your child with someone else.

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How to prepare formula milk

Formula milk manufacturers guidelines state you should make up fresh formula feeds as and when they are needed. This is because powdered formula milk is not sterile and may contain bacteria.

When a bottle is made up and left for longer than recommended, the bacteria can multiply to levels that could make your baby ill.

The correct way to make up each bottle is generally as follows:

  1. Wash bottles, teats, rings and caps thoroughly in hot soapy water, using a bottle brush to remove every last trace of old milk from teats and bottles, then rinse
  2. Sterilise bottles and bottle components
  3. Make sure your hands and kitchen surfaces used to prepare bottles are clean and disinfected (if you have a dish-shaped microwave steriliser, you can use the upturned lid as a sterile surface to prepare feeds)
  4. Boil fresh water in the kettle (do not use water that has previously been boiled) and allow it to cool slightly, but not for longer than 30 minutes – water must be at least 70 degrees C to kill bacteria
  5. Using the scoop provided, add the appropriate amount of formula milk powder to the appropriate amount of boiled water in the bottle (always add the water first so you know the water level is correct)
  6. Gently swirl or shake the contents to ensure the powder is completely dissolved
  7. Wait for the milk to cool down to body temperature (you can place the bottle in a jug of refrigerated cold/iced water to speed this up or hold it under the cold tap)
  8. Test the milk on the inside of your wrist to check it is not too hot or too cold
  9. Feed the baby and discard unfinished feed within two hours

As previously mentioned these guidelines are all well and good if you are at home all day, your baby is in a good routine and you are able to schedule exactly when to prepare a bottle.

How to prepare formula in advance

How to prepare formula in advance
Baby bottle on Picspree

If you feed your baby formula, you'll soon realise making 6 to 8 individual fresh bottles a day is a monotonous time-consuming task, and it can be tricky to get the timing exactly right.

Unsurprisingly, many time and sleep-deprived parents look for shortcuts to make their lives a little easier.

One option is to prepare several bottles of formula in advance and keep them in the fridge. This may seem like a more practical and convenient way of doing things, but it is not recommended by health professionals or formula milk manufacturers.

This is because the longer formula is stored, the greater the risk of bacterial growth (although bacterial infections from powdered infant formula are rare).

If you do decide to make up several feeds ahead of time, take the following precautions to minimise the risk to your baby:

As a compromise you could just make up bottles in advance for when it makes the most sense, such as for the middle of the night, for first thing in the morning, and for when you are going to be out of the house.

Transporting formula milk

If you are taking prepared bottles out with you for the day, make sure they are thoroughly refrigerated first for at least one hour, and carry them in a cool bag with an ice pack or a specially designed insulated bottle bag or thermabag.

Thermabags should be used to keep formula cold, not warm. Feeds transported in this way should be used within 4 hours, unless they are transferred to a refrigerator within this time (in which case they should be used within 24 hours of when they were first made).

Can you reheat formula milk?

Can you reheat formula milk?
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You can reheat baby milk if it has been made carefully in advance, cooled quickly and stored in the fridge as described above. Never reheat it more than once.

To warm a cold bottle of formula, you can:

How warm you heat the milk depends on your baby. Some babies like their milk room temperature, others like it warm, while other babies will drink it cold. Just make sure it is not too hot.

If a bottle of formula is kept above refrigeration temperature for more than two hours it could become a breeding ground for bacteria. You should always discard reheated unused feeds within two hours (never put them back in the fridge for later).

Other ways to prepare baby formula

Instead of making up bottles individually or making several up at once and putting them in the fridge, you could try these alternative methods:

Fill a vacuum flask with boiling water (this will stay hot enough for several hours). Put pre-measured amounts of formula into a milk powder dispenser, and assemble some sterilised bottles. You can then make up feeds more quickly and you don't have to boil the kettle each time.

You can put all of this equipment in a baby bag for when you are out, but you will still need time to cool the milk down.

You could also put sterilised bottles filled with cooled boiled water in the fridge. When it's time for a feed (for example an 8 oz feed), mix 3 oz of hot water from the vacuum flask with the pre-measured formula to kill bacteria, then top it up with 5 oz of cold water. The milk should be roughly the right drinking temperature straight away (you can experiment with the ratios).

Possibly the most controversial method is to put the correct amount of boiled water into sterilised bottles, let them cool and place them in the fridge. When it's time for a feed, reheat a bottle of water to the correct temperature and mix in the formula. Obviously this goes against the guidelines for mixing formula with hot water to kill bacteria, so this method is NOT recommended.

Ready made formula

Ready made formula in bottles or cartons is sterile until opened, and is the safest, easiest alternative to making up fresh bottles – simply add the formula milk to a sterilised bottle and you're ready to go.

But this option is much more expensive than powder. If you can afford it, you may find ready to use formula milk handy for night feeds, when you are out and about, and even when you are in hospital with your baby after the birth.

Formula milk prep machines

For a fast way of making up bottles on demand at home, a milk prep machine such as the hugely popular Tommee Tippee Perfect Prep Machine will do the job for you. This is a formula maker that will give you a fresh bottle of formula at the correct drinking temperature in under two minutes.

  • Makes a bottle in under 2 minutes
  • No waiting for bottles to cool
  • Compatible with most baby bottles
  • Works with most formula brands
  • Prepares the exact amount you want

The prep machine first pours a 70 degrees C 'hot shot' of water into the bottle – this kills any bacteria that may be present in the milk and helps the powder dissolve. Then you add the required amount of formula milk powder to the bottle (you can use any powdered formula milk) and shake to dissolve.

The dispenser will then top up the bottle with cool water and you're done – you have a fresh bottle of formula at body temperature ready to drink straight away. You can make up variable amounts of feeds depending on your baby's requirements – between 4 floz and 11 floz, and the machine is compatible with most baby bottles.

You can safely use water straight from the tap. The Perfect Prep machine has an anti-bacterial filter system to remove impurities and bacteria in the water, so it is as safe to use as boiled water from the kettle (except it's 10 x faster than a kettle).

For making bottles up quickly when you are at home (especially at 3 am), a milk prep machine could be the answer to your prayers. For making 6 - 8 bottles a day in under two minutes each, the use you will get out of it will make the investment well worth it.

Note: To use the Perfect Prep machine safely, you must only use Tommee Tippee filters with the machine, and not non-Tommee Tippee filters or standard water jug filters. Change the filter and run the machine's cleaning cycle as directed. You must still sterilise baby bottles and teats before use.

In conclusion it is best to make up bottles of formula milk when they are needed, but this is not always practical. You can: make up bottles in advance and carefully store them in the fridge for reheating later, fill a vacuum flask with hot water for making up bottles on the go, use ready made formula, and/or invest in a milk prep machine.

With all this in mind and a bit of common sense, you can find a suitable method to prepare baby bottles that works for you, without compromising your baby's health.

In addition to bottle feeding equipment, there are a few other things you will need to prepare for your baby's arrival.

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How to make formula milk in advance