How Do You Thaw Breast Milk Safely? – Baby Feeding Guide

Reviewed by
How do you thaw breast milk safely?
How do you thaw breast milk safely?

Thawing breast milk is not a too hard task, but it can be a little confusing if you are a first-time mother. Improper thawing methods can lead to the loss of nutrients or even create harmful bacteria. Thus, understanding the safe ways to thaw breast milk is very important. This will ensure your baby receives the full benefits from your breast milk. 

How do you thaw breast milk? In our guide today, we’ll walk you through some safe and effective ways to defrost breast milk. You will also learn tips to thaw breast milk quickly when you are in a rush, as well as what you should avoid when defrosting it. Keep reading to learn how to thaw breast milk properly and ensure your baby’s feedings are as healthy and safe as possible.

How Do You Thaw Breast Milk Safely?

You need to how to thaw breast milk safely to ensure your baby’s health
You need to how to thaw breast milk safely to ensure your baby’s health

Express breast milk, freeze, and defrost – This is what an after-giving-birth mother usually does. How do you thaw breast milk? Is it a good way? Let’s find out how best to thaw frozen breast milk to feed your little baby. 

Thaw breast milk In The Fridge

Defrosting breast milk in the fridge is the safest way but takes the longest time. So, it’s best to plan ahead. Ideally, you will need at least 12 hours (or overnight) to thaw frozen milk. Move the frozen breast milk container (bag or storage cup) from the freezer and place it towards the back of the refrigerator. Don’t place it at or near the fridge door. The temperature there will fluctuate when the door is opened and closed. This can make the milk spoiled. 

After 12 hours, gently squeeze the bag or container to see if the milk is thawed completely. If you still see some frozen chunks, wait for more time. Once the milk is completely thawed, gently stir it to ensure an even distribution of fat content. You may want to warm up the milk and have it ready for your baby to bottle feed.

You should use this defrosted milk within 2 hours. After that time, you should throw it away.Once your milk is warmed, the ability of the milk to inhibit bacterial growth is decreased, so it is not recommended to place your milk back in the refrigerator,” reveals Andria. The baby’s mouth touching the milk leads to bacterial growth in the milk.

Thawed milk can be kept at room temperature for 1 to 2 hours, and a maximum of 24 hours if stays in the fridge. Prioritize using older, previously frozen breast milk first.

Use Warm Water To Defrost Breast Milk

How to thaw breast milk quickly? - Use warm water
How to thaw breast milk quickly? – Use warm water

If you want to thaw breast milk quicker, using warm water is also a good option you can consider. Fill the container with warm water. The ideal temperature is similar to lukewarm bathwater  (37oC or 99oF)  – comfortable to the touch but not hot.  Excessively hot water can damage the nutrients in breast milk.

Place the frozen breast milk bag or container completely underwater. Make sure the seal is intact to avoid any water leakage into the milk. To accelerate thawing, gently swirl the container or bag occasionally in the warm water. This helps distribute the warmth evenly and speeds up the process.

Depending on the amount of milk frozen, it typically takes 15-20 minutes to thaw using warm water. The milk is thawed once it’s completely liquid with no frozen chunks.

Before feeding your baby, check the milk temperature. It should feel cool or lukewarm, not hot. You can use a sanitized milk thermometer or the back of your wrist for a quick check.

Once thawed using warm water, breast milk should be used within 2 hours to minimize bacterial growth. If your baby doesn’t use all the milk, discard any leftovers. Refreezing thawed milk is not recommended to maintain its quality and safety. 

How To Thaw Breast Milk Quickly?

You can defrost frozen milk quickly by running it under water. Place the frozen breast milk container under cool running tap water. This helps initiate the thawing process gently.

Once the milk begins to thaw around the edges, increase the water temperature to lukewarm. Gently swirl milk occasionally (but do not shake) to distribute the heat evenly and speed up thawing.

It usually takes about 10 minutes to thaw milk in this way. But if you are not in a hurry, the 2 thawing breast milk methods mentioned above are prioritized. This way works but will waste a lot of water. 

How Long Does It Take To Thaw Breast Milk?

This is the recap about the time to defrost milk from our content above:

  • In the fridge: at least 12 hours (best method)
  • In warm water: 15-20 minutes
  • Running under warm water: 10 minutes ( just use when you don’t have enough time)

What Should You Avoid Doing When Defrosting breast milk?

You shouldn’t defrost breast milk at room temperature
You shouldn’t defrost breast milk at room temperature

Breastfeeding is always the best for your little baby. So keeping it safe during thawing is essential. Here’s a guide to ensure your precious milk is perfectly defrosted.

  • Thaw At Room Temperature: Don’t leave frozen milk at room temperature to thaw. This can encourage bacterial growth, making it unsafe for your baby.
  • Thaw In Microwave: The heat from the microwave can create hot spots that can burn your baby’s mouth and destroy nutrients in the breast milk. This happens the same if you use a stove to defrost the milk. According to a policy statement from the AAP – American Academy of Pediatrics – published in the 2018 edition, thawing breast milk in the microwave can make plastic baby bottles leak phthalates, and BPA into the milk. These chemicals have been known to link to some health problems1.
  • Thaw With Boiling Water: Similar to microwaves, boiling water can damage the nutrients in breast milk2

Don’t Freeze Breast Milk Again: Just thaw enough milk to feed your baby at a certain time.

Thawed breast milk can sometimes smell odd, but still safe to be used.
Thawed breast milk can sometimes smell odd, but still safe to be used.

Why Does the Breast Milk Smell Odd After Being Frozen?

Breast milk naturally contains an enzyme called lipase. This enzyme helps break down fats in the milk, making it easier for your baby to digest. This breakdown during frozen storage can cause a slight soapy or sour smell.However, even if your breast milk smells different after freezing, it’s still safe for your baby to consume. Many babies don’t seem to be bothered by the slight change in the smell of breast milk.

Is It Necessary To Warm The Thawed Breast Milk Before Feeding The Baby?

Warming thawed breast milk is not necessary for healthy, full-term babies. They can safely drink breast milk that is at room temperature or even chilled directly from the refrigerator. However, some babies might prefer their milk slightly warmed. You can experiment by offering it at different temperatures to see what your baby enjoys most. It is not necessary to warm your breast milk and can be served cold or room temperature. Although, some babies may have a preference, says Wendi Andria, MSN, a lactation specialist at South Shore University Hospital, New York.

In case you want to warm breast milk, use a bowl of lukewarm water and submerge the breast milk container. Or else, you can use a bottle warmer. Always test the milk temperature before feeding. It should feel cool or lukewarm, not hot. 

Last Word from Babies Parent 

“How do you thaw breast milk?” – We believe that you’ve found the safest way to defrost breast milk after reading our guide. It is essential for preserving its nutritional value and ensuring your baby’s health. Always remember to avoid microwaves and refreezing thawed milk to maintain its quality. Don’t forget to check the milk temperature every time before you feed the baby.

  1. Ginter-Kramarczyk, D., Zembrzuska, J., Kruszelnicka, I., Zając-Woźnialis, A., & Ciślak, M. (2022). Influence of Temperature on the Quantity of Bisphenol A in Bottled Drinking Water. International Journal of Environmental  Research and Public Health/International Journal of Environmental Research and Public Health, 19(9), 5710. ↩︎
  2. Bransburg-Zabary, S., Virozub, A., & Mimouni, F. B. (2015). Human Milk Warming Temperatures Using a Simulation of Currently Available Storage and Warming Methods. PloS One, 10(6), e0128806. ↩︎

Esther Nash
Esther Nash

Esther Nash is an editor at the Babies Parent, where she writes and edits content about pregnancy, postpartum, and she also had experiences working with parenting for high-profile clients like Parents, Forbes Advisors, VeryWell Family, Apartment Therapy, and Dwell. Over an eight-year career in educational publishing and digital media, Esther has developed a sharp eye for detail and strong reporting skills. As a staff member at the Babies Parent for over three years, she combines her in-depth knowledge of essential baby gear and postpartum needs with a passion for the latest trends to create informative content parents can rely on.

Articles: 11