Feeding Formula

How Many Times Can You Reheat Formula? (And How To Avoid Wastage)

The cost of buying formula can really add up – a year’s worth for your baby can cost a staggering $1,200 to $2,000 or more.

So it’s only natural to wonder whether you can reheat formula twice to avoid wasting any product (and therefore money).

Infant formula should only be heated once, so it’s therefore not safe to reheat.

This is because reheating can lead to the growth of harmful bacteria, and also because many nutrients could be lost.

But does this also apply to bottles that have been made up and not touched?

How long can formula be kept in the fridge once mixed?

And is there anything you can do to avoid wasting the stuff?

Let’s take a look.

How Many Times Can You Reheat Formula?

Ideally infant formula should only be heated once and should therefore not be reheated twice.

This is for two reasons:

  1. If your baby has started the bottle, then the mixture of your baby’s saliva with the formula can encourage the growth of harmful bacteria.
  2. Even if the bottle is completely untouched after you’ve made it up, reheating the bottle again can lead to a loss of a lot of nutrients.

Does Formula Need To Be Heated?

You may be wondering whether babies actually need to be served warm milk or formula.

Surprisingly, the milk you give to your baby does not need to be warmed before feeding.

However, many parents prefer to give their child warm milk, and some babies are particularly fussy and refuse to drink cold or tepid milk at all.

So it really comes down to personal preferences – which includes both your preferences and that of your baby!

How To Heat Up Formula

One of the best ways to warm formula is by placing a made up bottle in a bowl of hot water, and leaving it to stand for 2-3 minutes.

This should be long enough to warm up the milk but not heat it too much, which could result in burning your baby’s mouth or tongue.

As a precaution it’s advisable to always test the temperature by tilting the bottle upside down and letting a couple of drops hit the back of your hand.

What you’re looking for is a temperature that is lukewarm, but not hot.

You should also swirl the bottle around to ensure all the milk is evenly warmed up.

Another way is by using a bottle warmer, which is a gadget designed to take the guesswork out of warming your child’s milk by quickly and consistently warming their bottle every single time.

Smeg Electric Kettle

Can You Microwave Formula?

According to the FDA, you should never use a microwave to heat formula for two reasons:

  1. A microwave will heat milk unevenly and may result in “hot spots” within the liquid that can burn your baby’s mouth or throat.
  2. Microwaving can destroy nutrients within the milk.

How Long Can You Keep Formula Once Made Up?

A bottle of prepared formula can be safely kept at room temperature for some time, so it does not need to be consumed immediately.

The general advice from experts such as the CDC is to use infant formula within 2 hours of preparation and within one hour from when the feeding session starts.

If you do not use the made up bottle with 2 hours, the good news is you do not have to throw it away – if the formula is completely untouched, then it can be stored in the fridge and used within 24 hours.

Keep in mind these are general guidelines, so it’s best to also check the back of pack label instructions just to be certain.

It’s also worth familiarizing yourself with the signs of formula that has gone bad.

How Long Can I Keep Formula Milk In The Fridge?

Formula that is prepared ahead of time can safely be stored in a refrigerator for 24-48 hours depending on the type.

Pre-made formula can be stored for up to 24 hours.

Ready-made formula, concentrated formula, and formula which has been prepared using concentrate can be stored in the fridge for up to 48 hours.

mother playing with baby

Can I Reheat Untouched Formula?

There is mixed advice about whether untouched formula can be reheated.

Those that say it’s fine argue that because the contents and bottle have not been touched at all, it is safe to place the contents back in the fridge and reheat again.

But on the flip side, others argue that to be on the safe side, it’s best not to reheat a bottle, even if it’s been untouched by your baby.

The argument against reheating untouched formula revolves around the fact that reheating baby formula may increase the chance of bacterial growth, and also because a lot of nutrients could be lost.

How Much Does Formula Cost Per Week, Month And Year

You can expect to spend around $25 to $40 on formula per week, which equates to $110 to $170 or more per month.

Looking at an entire year, the cost of buying formula for your baby is usually in the region of $1,200 to $2,000 depending on the brand you choose and quantity your baby needs.

Given this is a lot of money, let’s take a look at how you can avoid unnecessary wastage and save some money.

5 Tips On How To Avoid Wasting Formula

If you have bottles of formula that are unopened and you still have the receipt, then you should be able to return them and get a refund.

There are also some useful tips you can follow to avoid wasting formula, including:

Make Up Smaller Quantities

It can often be difficult to predict how much milk your baby wants.

In these instances you may find yourself preparing a large bottle only for your baby to have a few sips before falling asleep, leading to a lot of wasted product.

To guard against this, it can be a good idea to only make up smaller bottles at first, because you can always mix a bit more later if required.

Alternatively you can use a mixing pitcher (see below).

Use A Formula Mixing Pitcher

If you do find yourself having to frequently top up your baby’s bottle with a bit more formula (see the first tip), then you might find a pitcher like the one below very useful.

By using a pitcher you can make a larger amount of milk (several bottles worth) and then pour it into your baby’s bottle as and when needed.

This is a convenient and safe thing to do, provided you use the contents within 24 hours of mixing.

Top tip: Try to get one with an adjustable time ring that helps you keep track of when the formula was prepared.

Munchkin® Smart Blend™ Formula Mixing Pitcher ($11.49, Amazon)

Determine Bottle Size Based On Last Feed

Another hack is to vary the bottle size based on your baby’s last feed.

So for example if your baby’s last bottle was a small one and it was a couple of hours ago, there’s a good chance you little one will want a relatively large bottle at the next feed (and vice versa).

Avoid Mixing Ahead Of Time

When you’re traveling by road or plane, it can be tempting to make up bottles ahead of time, especially as liquids for babies can be taken on planes in quantities greater than the usual 100ml limit.

But to avoid wastage you might want to consider packing the water and formula separately, and then mixing them together just before your baby’s feed.

Serve Cold / Room Temperature

As mentioned above, some babies simply refuse to drink formula or milk that has not been preheated and offered to them warm.

But if you can get away with giving your baby cold or room temperature milk, then you won’t have to worry about heating their bottle at all bottle, so the issue of warming up formula twice won’t be a problem.

In Conclusion:

  • Infant formula should only be heated once to avoid the growth of harmful bacteria, and to ensure no nutrients are lost.
  • Once made up, formula that is stored out of the fridge should be offered to your baby within 1 hour and discarded after 2 hours.
  • Made up bottles can be safely stored in the refrigerator for 24-48 hours depending on the type.
  • Making up smaller bottles, using a mixing pitcher and preparing bottles only when needed are some of the ways to reduce waste and save money on baby formula.

Related: Your Must Have Baby & Toddler Feeding Guide

Tori is mama to 3 year old Isabella and co-founder of Rockinbaby. She has a BSc in Psychology, is a certified yoga teacher and is a working mom. In her free time Tori loves cooking delicious foods and baked treats, entertaining and working out. Learn more about Tori here.

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