How to warm up a baby bottle

Lots of folks think you have to warm up a bottle before giving it to your baby. While warming a bottle isn’t necessary, and cold infant formula or breast milk is perfectly safe, lots of babies prefer their bottles to be warm. But there are not-so-safe and safe ways to heat up a bottle, so read on for the dos and don’ts to make sure you’re warming up your baby’s bottle safely!

Do you have to warm baby bottles?

Whether or not you warm up a formula bottle before you give it to your baby may depend on if you have just made the bottle or if your bottle has been refrigerated. And this decision really just depends on what your baby likes.¹ Warm and cold bottles bottles are both safe, you just don’t want the bottle to be too hot or it can burn your baby’s mouth.

Safe ways to warm up a baby formula bottle

How to warm a baby bottle under running water:

Simply turning on your tap water for bottles up to a warm temperature and running the bottle underneath the stream of water can work well to heat it up to the right temperature. Just be sure to keep the nipple covered while you are doing this so the water doesn’t get on or into the nipple.² 

How to use a baby bottle warmer:

Store-bought bottle warmers can be a handy tool for heating up baby bottles. They are available in portable versions for when you’re on the go and countertop versions to use in your home.¹ Of course, a bottle warmer isn’t necessary, but it can help simplify the task.

Can you use a portable bottle warmer?

Portable baby warmers can be used when you’re on the go or in the car to warm up your baby’s bottle. Just follow the manufacturer’s instructions for your model. 

How to warm a baby bottle using a pan of warm water:

Placing a bottle in a container or pan of warm water works well to heat it up slowly and evenly. If you use the stove to warm up the water, be sure to take the pan off the hot burner before placing the bottle in it.¹ Don’t leave the bottle in the warm water for more than 15 minutes.³ 

Can you use a microwave to heat up baby formula?

NEVER use the microwave to warm up a baby bottle. Because microwaves heat unevenly they can cause hot spots that will burn your baby’s mouth.⁴

Tips for warming a baby bottle:

No matter which method you choose for warming up a baby formula bottle, here are a few very important items to remember:

• Don’t remove a bottle from the fridge until you are ready to heat it up.³
• NEVER use the microwave to warm up a baby bottle. Because microwaves heat unevenly they can cause hot spots that will burn your baby’s mouth.⁴
• Make sure to shake or swirl the bottle before giving it to your baby so the heat is evenly distributed.³
• Always test a few drops on the inside of your wrist before giving the bottle to your baby to make sure it’s not too hot.¹

How to warm up a breast milk baby bottle:

There are some similarities and some differences between warming up a formula bottle and warming up a breast milk bottle. 

If you’re warming up a bottle of breast milk from the fridge, you can use the same methods listed above for formula bottles. It’s especially important to warm breast milk slowly to preserve its nutritional value. 

How to thaw breast milk:

One big difference between infant formula and breast milk is that breast milk can be frozen and formula cannot. Breast milk can be stored in a freezer for 3 to 6 months, which means you might build up quite a stash!⁵ 

When your breast milk is frozen instead of refrigerated, it just adds one more step to the process of getting it ready for your baby since you need to thaw out the frozen milk.

Breast milk can be slowly thawed in the fridge overnight. This method is the best for maintaining the fat content of the milk.⁶

Sometimes (like when you have a crying, hungry baby!) you may need to thaw breast milk faster than overnight. When this happens, you can also use the running water, bottle warmer, and pan of warm water methods described above.⁶ 

Tips for warming breast milk:

Just like with formula bottle feeding, there are a few items that apply to all breast milk bottles no matter how you choose to heat them up:⁶ 

• NEVER use a microwave to heat up breast milk (frozen or refrigerated). Similar to formula, this will create hot spots. In addition, microwaving breast milk can break down some of its valuable healthy components.
• Once frozen breast milk is thawed, it should be used within 24 hours.
• Be sure to shake or swirl a breast milk bottle before serving. 
• Test a few drops of breast milk from the heated bottle on the inside of your wrist to make sure it’s not too hot.

Heating up baby bottles:

Some babies are more than happy with any temperature baby formula or breast milk you offer them, while others favor a warmer bottle. This may be especially true for breastfed babies who are used to the naturally warm temperature of breast milk. 

It’s perfectly fine to heat up your baby’s bottle, just be sure to do it using one of the safe methods described above. Never use a microwave for any part of the process and be sure to do a final check before feeding it to your baby to ensure it’s not too hot.

Sources:

1- Formula feeding FAQs: preparation and storage | Nemours Kids Health

2- Infant formula preparation and storage | Centers for Disease Control and Prevention

3- How to prepare formula for bottle-feeding at home | World Health Organization

4- Feeding your infant: how to prepare and store baby formula | Cleveland Clinic

5- Storing human milk | La Leche League International

6- Heating human milk | La Leche League International