How to Warm Up Breast Milk 101

Nature intended for babies to drink warm milk, so why not serve them what nature wants? Babies prefer warm milk over anything else because a mother’s breast milk - your “liquid gold” - is at or near the average human body temperature of 98 degrees before it’s stored.

According to Dr. Jacqueline Winkelmann, a Pediatrician and former Chief of Staff at the Children’s Hospital of Orange County, serving “cold breast milk or formula might lower the body temperature of a newborn, which can be risky.” When a baby’s body temperature drops, oxygen use increases, putting stress on the tiny body. Your baby could become fussy, exhausted, and experience stomach aches.

Warming Breast Milk

Protect your liquid gold by warming it properly. When it’s time to warm your breast milk, stay away from the microwave – no matter what. It’s great for warming last night’s leftovers but will ruin the nutrients in breastmilk because of the high heat. Microwaves also don’t heat evenly which can be dangerous to your baby. According to a review from BabyGearLab,

“microwave ovens do not heat liquids evenly. Uneven heating could easily scald a baby or damage the milk. Also, bottles may explode if left in the microwave for too long.”

Yikes!

You’ll also want to avoid boiling a bottle in hot water. If you’re using a plastic bottle, you might run the risk of melting it. High heat can also deplete the nutrients in breast milk, and waiting for the water to boil is just too time-consuming.

“The key to warming breast milk while preserving its full nutritional value is to avoid overheating,” 

according to the BabyGearLab review. That’s where the Baby Brezza Bottle + Breastmilk Warmers comes into play.

Does Boiling Breast Milk Ruin It

Yes, boiling breast milk can ruin it by destroying essential nutrients and antibodies. Breast milk contains delicate proteins, enzymes, and immune-boosting components that provide vital health benefits for your baby. When exposed to high temperatures—especially boiling—these nutrients break down, reducing its overall nutritional and immune-supporting properties. Instead of boiling, it's best to gently warm breast milk using a warm water bath or a bottle warmer designed to preserve nutrients, like the Baby Brezza Safe + Smart Bottle Warmer, which uses a steady, controlled temperature to warm milk safely without overheating.

Can You Warm Breast Milk in a Bottle Warmer?

Not all bottle warmers are created equal when it comes to warming breast milk. Some models use hot steam to heat bottles quickly, but this high temperature can break down essential nutrients and antibodies in breast milk, reducing its benefits for your baby. Baby Brezza bottle warmers, however, are designed with precision to gently warm breast milk while preserving its vital nutrients. With safe, even heating methods like warm water baths or steady temperature control, Baby Brezza ensures your baby gets all the nourishment they need without the risk of overheating or nutrient loss.

The Baby Brezza Smart Bottle + Breastmilk Warmer is your go-to solution for warming breast milk (and formula too) properly. It is the only bottle warmer that safely and evenly warms breast milk and formula because it has two settings - Steady Warm and Quick Warm.

Steady Warm is perfect for breastmilk because it uses a warm water bath to warm or defrost breastmilk, preserving its nutrients. Traditional bottle warmers use steam heat to warm breast milk, which is too hot and destroys proteins. 

Quick Warm on the other hand is ideal for formula. It uses steam heat to rapidly warm formula or baby food which can withstand higher temperatures produced by steam heating. 

This Baby Brezza warmer is also the only bottle warmer with Bluetooth. So you can use the FREE Baby Brezza app on your mobile device to operate the device and receive updates when your bottle is ready. That’s the “smart” part of the warmer.

Don't have a need for the smart version? No problem! Check out the Bottle + Breastmilk Warmer.

How to Warm Breast Milk On-The-Go

Warming breast milk on-the-go can be a challenge, but the Baby Brezza Portable Bottle Warmer makes it effortless. Unlike traditional warmers that require bulky water reservoirs or outlets, this compact, battery-powered device allows you to pour breast milk or formula directly into the warmer for quick, even heating. When it's ready, you can conveniently unscrew the lid to pour the milk or use the 360° pour spout for mess-free feeding. Whether you're traveling, running errands, or out for the day, this portable warmer ensures your baby’s milk is always at the perfect temperature—anytime, anywhere. It’s small enough to fit into a cupholder, diaper bags, backpacks, and strollers.

What If My Baby Doesn’t Finish The Bottle After Warming Up Breast Milk?

Now that you’ve warmed your liquid gold, your baby can start drinking! If he or she doesn’t finish the whole bottle of breast milk, you’ll want to dispose of the remains within 2 hours after the initial heating and feeding, according to the Centers for Disease Control and Prevention. Refrigerating already warmed breastmilk is not recommended.

Don’t forget to properly sterilize your breast pump parts and bottles regularly to make sure your feeding accessories are free of germs.

Do You Have to Warm Breast Milk?

No, you don’t have to warm breast milk, but many parents choose to do so because it closely mimics the natural temperature of milk as it comes from the breast, making it more familiar and comforting for babies. Some babies prefer milk at room temperature or slightly warmed, while others are fine drinking it cold straight from the fridge. It really depends on your baby’s preference.

Warming breast milk can also make it easier for babies to digest. Cold milk may sometimes cause slight discomfort, especially for newborns with sensitive stomachs. However, if your baby is happy drinking cold milk, there’s no harm in continuing that practice.

If you do decide to warm breast milk, it’s important to avoid using a microwave, as it can cause hot spots and destroy vital nutrients. A baby bottle warmer is a more consistent and safe method, ensuring that the milk is warmed evenly and gently. Ultimately, whether or not you choose to warm breast milk is up to you and your baby’s preferences. As long as the milk is properly stored and handled, cold, room temperature, or warmed milk will provide the same nutritional benefits to your baby.

By following these do’s and don’ts, you’re ensuring your baby gets 100% of the goodness from your liquid gold!