How to Defrost Breast Milk Safely | Baby Brezza
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How to Thaw Frozen Breast Milk the Safe Way

So you’ve been storing your breast milk in the freezer and are now ready to use that liquid gold that’s been hiding behind the ice cream. Knowing how to thaw breast milk correctly is essential. Improper thawing can negatively affect the nutritional properties of the milk and make it unsafe for your baby. What are the safe ways to thaw frozen breast milk, and what methods should you avoid? We give you the breakdown below.



It takes approximately 12 hours to defrost breast milk in the refrigerator. Know you will need milk in the morning? Move it from the freezer to your fridge in the evening and let it thaw overnight.

Hold a bag or bottle of frozen breast milk under warm running water. Start at a lower temperature and gradually increase the heat to a maximum of 99 degrees F.


For your own DIY frozen breast milk bag warmer, parents can place their bag or container of frozen breast milk in a bowl of warm — not hot — water.

When using a bottle warmer, frozen breast milk can be sensitive: bottle warmers can defrost breast milk, but traditional bottle warmers use only steam heat, which is too hot and can destroy those all-important breast milk proteins. Look for a frozen breast milk warmer that will preserve milk nutrients. An excellent option is the Baby Brezza Safe + Smart Baby Bottle Warmer. It’s the only warmer with two settings, one for breast milk and another for formula, to ensure both are safely heated to the right temperature. Thawing breast milk in a bottle warmer doesn’t have to be a balancing act that puts important nutrients at risk: the frozen breast milk warmer helps parents do feeding time more safely.

If parents are wondering how to thaw frozen breast milk in a bottle warmer, our bottle warmer keeps it simple. For breast milk, the Steady Warm setting on the frozen breast milk bag warmer uses a warm water bath (instead of steam) to safely defrost breast milk. The warming basket fits most milk storage bags, plus you’ll never have to worry about overheating thanks to its auto shut-off.

For formula, the Quick Warm setting uses steam heat to rapidly and safely warm formula and baby food. Even better -- it’s the only smart warmer, so you can operate it from your phone with Bluetooth using the FREE Baby Brezza app and get alerts when your bottle is ready.

For moms who are not particularly tech-savvy or just don’t want the added Bluetooth function, we introduce the Baby Brezza Bottle & Breastmilk Warmer. Get the same settings and intuitive design at a more affordable price, and thaw breast milk in a bottle warmer the better, safer way.


Can You Defrost Breast Milk & Put It Back in the Refrigerator?

Once you thaw breast milk in a bottle warmer, parents have a small window of time to work with it, whether they go ahead and use it for feeding time or store it for a little longer. After using a frozen breast milk warmer, you can use the milk immediately, leave it out (at room temp) for a maximum of 4 hours, or store it in the refrigerator for another 24 hours.

Can I Mix Breast Milk from Two Different Days?

When learning how to thaw breast milk properly, there are a few extra guidelines to keep in mind, such as blending milk from different days. Once you thaw breast milk in a bottle warmer, it is highly advised to keep batches separate– meaning parents should not blend milk from different days. While a frozen breast milk bag warmer makes warming convenient, blending and reheating milk together from different days runs the risk of rewarming old nutrients that shouldn’t be combined with a fresh batch, ruining them both.

Can Babies Drink Cold Breast Milk?

Babies can absolutely drink cold breast milk, as the temperature does not have an effect on breast milk’s nutritional composition. However, most babies tend to take to warm breast milk or formula more easily due to it replicating natural warmth from the body. This is why thawing breast milk in a bottle warmer is useful: it takes less time to thaw, and your bottles are ready for feeding time with perfectly warm milk.

Baby Feeding & Formula Prep

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