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Can You Reheat Breastmilk Twice or More Than Once?

Can You Reheat Breastmilk Twice or More Than Once-

So, you’ve decided to breastfeed your baby.

You may have also decided to express breast milk, especially if you want to give your nipples a break. 

You may wonder what to do with unfinished breast milk if you’re a first-time mother. After all, your baby won’t always finish a full bottle of breast milk.

What should you do with any leftover breast milk?

In this guide, we will go over some helpful breastfeeding tips to ensure your baby stays healthy!

Table of Contents
Table of Contents

What You Need to Know About Expressed Breast Milk & Reheating

Breastfeeding is not always convenient.

For instance, you may find yourself away from your baby for long periods that you could miss their feeding period!

There may also be times when your breasts may be too engorged or your nipples are too sore to feed.

If feeding your baby store-bought formula is out of the picture, the best way to feed them is to express breast milk. This can be done manually or through a breast pump to store milk for later feeding.

If you do so, you may want to reheat the pumped milk to make it more palatable for your baby.

How can you make sure that you reheat the milk properly for a healthy baby?

According to the Academy of Breastfeeding Medicine, the safety and quality of reheated breast milk depend on the following:

  • Cleanliness of milk expression method
  • Length of time spent unused
  • Storage temperature
  • Warming method used

It is recommended not to give reheated or unused breast milk to any baby younger than 3 months.

If you feel bad about dumping out your liquid gold, there are many other uses for breast milk.

  • Moms have been known to use breast milk to fade stretch marks from pregnancy.
  • You can even get it preserved as a gem for you to hold and reminisce about your child’s innocence when they have grown into teenagers!

Can You Reheat Breast Milk?

Generally, it is safe to reheat breast milk and feed it to your baby within 4 hours.

Any longer than that, and it is best to throw it away. 

TAKE NOTE: There is no sufficient research supporting whether unused breast milk can be reheated and used for feeding more than one time.

How Many Times Can You Reheat Breast Milk?

You may be wondering how many times you can reheat and feed the milk.

While many moms have admitted to reheating breast milk more than once, it is best to only reheat breast milk ONCE to avoid getting your little one sick.

Reheating breast milk many times increases the chances of bacteria and spoilage in the milk.

This kills off a lot of nutrients and good bacteria that your baby needs while increasing the chances of hurting their sensitive immune systems.

How to Reheat Breast Milk Properly

If you must reheat breast milk, it is important to know how to do it properly!

Let’s go through how to reheat milk for your baby:

Step 1: Store the Leftover Milk Properly

Woman by refrigerator

If you have any intentions of reheating and using leftover milk, it needs to be put in the refrigerator ASAP.

Leftover milk must be stored in the fridge and used only up to 4 hours after.

Proper breast milk storage done IMMEDIATELY is key to preserving nutrients and keeping them from spoiling. You can find breast milk storage guidelines further down this article.

If you’re interested in preparing some dairy-free freezer meals, you can read our guide here!

Step 2: Check Breast Milk Quality

Packs of breastmilk

Once you’re ready to use and reheat the stored milk, make sure to check the quality.

Use all five senses to know whether or not the milk is still good for reheating and feeding. 

Some signs of spoiled milk would be:

  • Lumpy consistency
  • Strong smell
  • Yellowing/color change
  • Sour taste 

THROW IT OUT if you notice any of the above signs in your milk!

NEVER feed spoiled milk to your baby!

Step 3: Carefully Reheat Breast Milk

Heating breastmilk

Slowly but surely is the way to go when reheating milk. That being said, be sure to AVOID MICROWAVING when reheating breast milk.

Microwaving heats the milk unevenly, resulting in hot spots that can burn the baby’s mouth and throat.

The heat in these spots can also destroy the nutrients in the milk.

Here are some SAFE ways to reheat milk:

Warm Water

Place the breast milk container in a bowl of warm water for around two minutes. You can also put it in a pot of water over the stove for the same amount of time. 

This method will gently heat the breast milk and can also be used to thaw frozen milk. 

Running Water

You can also reheat the breast milk by holding the container under running warm or hot water.

Take note that this method will take more time and effort than just leaving it in a bowl of lukewarm water.

Bottle Warmer

A bottle warmer is a very convenient and ingenious piece of technology that can make your life so much easier!

As specified by the name, a bottle warmer, well, warms bottles.

You can just pop the bottles into the device and wait for them to be ready.

Most bottle warmers have different functions and sizes for different bottles, and some even have an auto shut-off feature to avoid overheating. Others even have an alarm to let you know when the milk is ready!

We recommend getting a bottle warmer for maximum convenience and safety!

Step 4: Check the Temperature of the Milk

Baby bottle with mother and baby in the background

Milk that is too hot can burn or scald your baby’s sensitive mouth and throat, leading to painful (and expensive) complications!

Make sure that the milk is around body or room temperature. You can test the temperature by dripping some milk onto the inside of your wrist.

Warm breast milk should just be LUKEWARM, not too hot or cold.

NOTE: If you feel any heat from the milk, it is best to let it cool down first before feeding it to the baby. You can just wait for it to come to the right temperature eventually. You can also run the bottle under some cold running water to speed up the process. 

When you don’t feel any noticeable heat from the milk, that’s when you know it is ready for feeding to your precious one.

When You Should NOT Reheat Breast Milk

Packs of breastmilk

NEVER reheat the milk if:

  • It has been sitting out for more than half an hour.
  • It has been previously reheated.
  • It is still frozen.
  • It looks like it has gone bad.
  • Your baby is a preemie.
  • Your baby is sick or immunocompromised in any way. 

It is important to note that reheating human milk causes it to lose most of its immunological properties.

A research study in 2015 suggested that human milk that has been heated to above 143º F has lost much of its live cells and essential nutrients.

As such, it is best not to reheat breast milk many times. At most, it is best to reheat it only ONCE.

Tips for Storing Breast Milk Safely for Reheating

As mentioned earlier, proper milk storage is key to ensuring that breast milk is not contaminated. It also makes all the difference in whether or not you can reheat and use any leftover breast milk.

Here are some tips and storage guidelines for breast milk:

  • Be sure that your hands and pump parts are clean and sterilized even before pumping and storing milk.
  • Carefully wash the pump and all breast milk storage bags and bottles you will use in hot soapy water to eliminate harmful bacteria. 
  • When storing milk, you need to put them in the appropriate bags or bottles in the fridge or freezer. You can label the containers with the pump time and date to ensure that you’re using them before expiry.
  • Be sure that the breastmilk containers are stored in sterile, BPA-free, and secure containers. Additionally, it’s always better to bottlefeed your baby using organic baby bottles!

Frequently Asked Questions

Woman feeding baby

Should I Breastfeed?

According to the American Academy of Pediatrics (AAP), the World Health Organization (WHO), and the American Medical Association (AMA), breastfeeding is recommended for the first 6 months of your baby’s life.

Breastfeeding helps strengthen the immune system and fight infections due to the antibodies and good bacteria found in breast milk. 

It is especially recommended for premature babies!

When you feed your baby breastmilk, you protect them against:

  • Allergies
  • Diarrhea
  • Ear infections
  • Respiratory infections
  • Meningitis
  • Diabetes
  • Obesity
  • Sudden Infant Death Syndrome

In addition to the above health benefits, breast milk is completely free instead of formula milk, which you will have to buy at the store.

You can see our full list of essential breastfeeding items to help you out!

Additionally, breastfeeding can help improve the bond between moms and babies due to skin-to-skin contact.

How Long Until Breast Milk Goes Bad?

According to the Academy of Breastfeeding Medicine, bacterial contamination occurs in breastmilk that you pump once the baby has drunk from it.

This is due to any bacteria in the baby’s mouth that could have transferred into the expressed human milk while drinking.

This can cause breast milk to spoil and get your little one sick.

Be sure to use stored breast milk within the following periods:

  • Freshly expressed breast milk at room temperature: 4 hours
  • In a fridge: 8 days
  • In the freezer of a fridge: 2 weeks
  • In a separate freezer: 3-4 months
  • In a deep freezer: 6 months to a year
  • Thawed breast milk at room temperature: 1-2 hours*
  • Thawed breast milk in the fridge: 24 hours*

*counting from when first defrosted

Can Reheated Breast Milk Go Bad?

The answer to this is YES. Reheated milk can go bad if not used within 2 hours.

Under certain conditions, it can go bad even sooner than that!

Here are some signs that milk has gone bad for feeding:

  • Foul smell
  • Sour taste
  • Separated layers

Breastmilk will often separate into fatty and non-fatty layers when refrigerated.

If these layers do not combine when you shake the container, this is a sign that the breast milk has gone bad.

If your milk shows any of the above signs, you need to toss it out immediately before it makes your little one sick!

Can I Refrigerate Unused Breast Milk?


Heat can encourage the growth of bad bacteria that can get the little one sick. 

We recommend refrigerating unused breast milk to help slow down their growth.

Can I Refrigerate a Bottle of Breast Milk That’s Been Heated Up?

Yes, but you need to use the heated milk within 2 hours.

If it is not used within that time, you risk harming your baby.


If you decide to pump breast milk for later feeding, you may wonder if you can reheat it more than once.

The answer to this is NO. You can only reheat breast milk one time.

After that, it is already too risky for your baby.

Reheating breast milk is not ideal, but we understand why you would do it.

If you must, be sure to take note of all the proper guidelines for breast milk storage for a healthy baby. If you follow our tips for proper storage and heating, you know you will be feeding your baby the right milk.

However, if, at any point, you don’t feel safe with the milk, it is best to throw it out than risk anything!

FINAL TIP: For all the new moms out there! You can get yourself an organic nursing pillow to make your breastfeeding experience more comfortable for you and your baby! Check out our buying guide here!

About the author

Angelica Graham

A few years ago, Angelica found out about all the plastic and toxic ingredients that got into most children’s products. And this worried her to no end. Because of this, she began to research what the best ingredients and materials were for children and made it her mission to share this information with other mothers.