The Best Way To Warm Breast Milk

New parents are often confused about what is the best way to warm breast milk.

Breast milk is best warmed by holding the container of milk under cool running water and gradually adding warm water until the milk is warmed to room temperature. If you don’t have a bottle warmer, you can microwave a bowl of hot water for 60-90 seconds and put the bottle in that for a minute or so to warm. This is less easy to do in the middle of the night with a baby to juggle, but it’s much faster than running a bottle under warm water in the sink.

The best way to heat your breastmilk isn’t rocket science, but many new moms aren’t sure what works best! I explain all this here…

Why Warm Up Breast Milk?

Why do some parents warm milk before giving it to their baby? Some babies have a certain preference on what temperature their food is. It’s worth it when you have a fussy baby and giving them a nice warm bottle is the one thing that will calm them down.

Why Warm Up Breast Milk by Running It Under Tap Water?

The most common and best way to warm breast milk is by running it under tap water or using a bottle warmer. The best way is under cool running water because it helps maintain the temperature and is gentle on your baby’s tummy when it gets too cold.

Can You Warm Breast Milk in the Microwave?

It is not recommended to warm breast milk in the microwave oven for a couple of reasons.

  1. You can kill off all of the nutrients that are in the breast milk. If breast milk is heated up too quickly or too hot, it can kill off all of the amazing nutrients and antibodies that your breast milk contains.
  2. You can create hot spots that can scald your baby’s mouth. The microwave is known for uneven heating and it can have ice-cold breast milk along with scalding hot breast milk all in one bottle. No one ever likes food being heated up unevenly but this especially can be dangerous for your baby.

What is The Best Way to Thaw My Milk?

One of the best ways to thaw your milk is to let it slowly thaw in the fridge overnight. This helps preserve the nutrients in your milk as well as the fat content that is much needed for your baby.

What is The Best Way to Warm Breast Milk?

To ensure keeping your milk of the best quality, the best way to warm up breast milk is to run it under cool water and to slowly warm up the water. Once the milk is warm, gently shake the bottle to mix the fat content evenly into the milk. Then check the temperature by adding a drop onto the inside of your wrist.

How Do You Warm Breast Milk Quickly?

Here are some ways to quickly warm your breast milk for night feeding or for when you have an extra hungry baby.

1. Leave your pumped milk out at room temperature after you use your breast pump

When you store breast milk in the fridge it will be much cooler starting out. The Center for Disease Control (CDC) says that you can leave your freshly pumped breast milk out for up to 4 hours. When it is already at room temperature, it will warm up much quicker. This will only be for fresh breast milk, if you are using leftover milk or previously frozen milk, then it will have to be stored in the fridge.

2. Use a bottle warmer to warm your milk

Bottle warmers are made to quickly and efficiently warm your breast milk and formula for you. Some you can even place the whole bottle of milk in it frozen to be stored overnight so it is ready for you when your baby wakes.

3. Use a bowl of warm water

Place your milk in a bowl of warm water until the human milk has warmed up to body temperature.

4. Try skipping warming it up altogether

Some babies will take a bottle at any temperature and are ok with taking cold bottles. Try when your baby isn’t too hungry or overtired so they are more willing to try something new. You might be surprised that they don’t mind cold milk at all!

Heating Breast Milk On The Go

1. Bring Thawed Bottles

Leave your milk in the fridge overnight so that it is already thawed and ready to go. This way the baby bottle will warm up quicker when you are out.

2. Bring an Insulated Cooler

There are lots of insulated coolers to store your breast milk. Since your milk will already be thawed, it’s a good idea to use a cooler with frozen ice packs for your bottle of breast milk.

3. Use Portable Bottle Warmers

There are some great travel warmers out there. Even some that you can use in your car! Once your baby is ready to eat, just use your travel warmer to heat up their bottle.

Can You Overheat Breast Milk?

Yes. You can overheat breast milk and kill off all of the antibodies and those beneficial nutrients that are in your breast milk. Be careful not to use hot tap water when you are warming your milk. It’s important to slowly warm your milk and to be careful to not overheat it.

Does Heating Change Breast Milk?

You can see after you use your electric pump and store your milk in the fridge that it can change. When breast milk is being stored in the freezer or fridge, the fat content will separate and rise to the top. When you warm up your milk be sure to gently shake it up to mix the fat content back in.

Storing Breast Milk

If you are storing your breast milk in the fridge, you will want to store it in the back of the fridge where it is more consistent and have the fridge at 40 degrees Fahrenheit or below.

To freeze breast milk, store it in the back of the freezer clearly labeled and use it within 3-6 months.

It’s important to have your milk clearly labeled with your baby’s name, as well as the date and the time it was pumped if you are passing it over to your childcare provider. Be sure to use the oldest milk first to ensure your milk doesn’t go bad.

When Breast Milk Goes Bad

There are some things to watch out for if your breast milk has gone bad.

1. Curdling

Curdling is a sure sign that your breast milk has gone bad. It’s normal for it to separate but if it doesn’t easily mix then it might have gone bad.

2. Sour Taste

You can always taste your milk to make sure it is safe to give to your baby. If it has a sour taste then it’s best to toss it

3. Play it Safe

It’s hard throwing away your liquid gold but when in doubt, it’s best to play it safe when it comes to feeding your baby. If you are unsure about the quality of your stored breast milk, then it’s best to toss it and give your baby freshly pumped milk.


Breast milk is one of the best ways to nourish your baby. It’s important that you know how to keep it cold and warm up in a pinch when necessary. Now you have an efficient system for storing and warming your breast milk so that both mommy and baby are happy!

About the author

Lacy Reason is a highly experienced and compassionate lactation counselor, who has dedicated her career to educating and supporting new mothers on their breastfeeding journey.