How to Freeze Breast Milk – Tips for Safe Storage

So you started building a supply of breast milk, or maybe you just pumped a little extra today, and now you are not sure How to Freeze Breast Milkwhat to do with it or how to safely store it for future use.

No worries, in this article we will discuss how to freeze breast milk and some other tips for storage.

Rules for Storing Breast Milk

Many moms are concerned about the safety of storing breast milk, and for good reason. Food contamination is a real thing, even for breast milk that is full of antibodies. After all the work that goes into pumping, no mother wants to put their baby in harms way or cause some bought of digestive problems or food poisoning because of milk that has not been stored properly.

So what are the rules for storage? Most moms will follow the 6,6, 6,12 rule. The rule states that you can leave freshly expressed milk out at room temperature for about 6 hours, you can store it in an air tight storage container or bottle in the back of the fridge for about 6 days, you can freeze it in a freezer with a separate door then the fridge for about 6 months, and you can freeze it in a deep freezer for about 12 months. This rule is followed most often because it is easy to remember and leaves out the guesswork, but if you want more details or specific ranges, there are more guidelines for safe storage listed below.

Freshly Expressed Milk

  • Good for about 3-4 hours if left out at warm temperatures (between 80-90 degrees Fahrenheit)
  • Good for about 4-8 hours if left out at room temperatures (between 61-79 degrees Fahrenheit)
  • Good for about 24 hours in an insulated cooler with ice packs (around 59 degrees Fahrenheit)

Expressed Milk Stored in the Fridge

*It is the best practice to store milk in the back of the fridge away from the doors*

  • If the milk was freshly expressed milk that was placed in the fridge, it will stay good between 3-8 days
  • If the milk was previously frozen it will only be good for 24 hours in the fridge once thawed.

Frozen Milk

*NEVER refreeze thawed milk*

  • If the milk is stored in a freezer compartment that is inside of a fridge (only one door to the outside) the milk will be good for 2 weeks because it is more difficult to regulate the temperature in that type of freezer
  • If the milk is stored in a freezer unit that has its own door to the outside, it is good for about 6 months
  • If the milk is stored in a deep freezer, it is good for about 12 months.

Freezing Tips

  • It is the best to freeze breast milk in smaller increments to avoid waste, between 1-4 ounces in each container. (Personally I freeze my breast milk in 4 ounce increments because that is how much my baby takes at each feeding)
  • There are many storage containers available specifically for freezing breast milk. Reusable ones are available for sale, but I personally like the disposable freezer storage bags because you can lay them flat to freeze which creates way more space in the freezer and fewer dishes! Plus if you end up with a large freezer stock, I am not sure the reusable containers would be very practical. There is an idea of what these bags look like in the image shown above.
  • It is alright to combine milk from more than one pumping session even over the course of a couple days into containers or bags to freeze (as long as it is within the guidelines listed above)
  • Make sure to always label your bags or containers with the most recent date that milk was added
  • Rotate your freezer stock so that the milk that was frozen most recently is always in the back, that way you will always use the oldest milk first and avoid waste.
  • Try not to add warm or very freshly expressed milk to a container that has already been in the fridge or frozen, make sure to cool the milk before adding.

Thawing and Warming Tips

  • The best way to thaw frozen breast milk is to pull it out of the freezer the night before you plan to use it and let it sit in the fridge for about 12 hours.
  • Not everyone has this kind of time or organization, so if you are unable to pull milk out the night before, it is safe to thaw it more rapidly by holding the frozen container or bag under running water and increasing the temperature slowly until the milk has thawed.
  • It is safe to store thawed milk in the fridge for up to 24 hours
  • Never refreeze fully thawed milk as it risks contamination. If the milk is still partially frozen, it is alright to refreeze.
  • To warm milk that has been in the fridge you can either use a bottle warmer, or place the container of milk in a cup of heated water until warm.
  • Never microwave breast milk because things do not always heat up evenly in the microwave and heat spots could form and some milk may be too hot for the baby.
  • Also, microwaving can damage the proteins in the breast milk which will decrease the nutrition contents and benefits of the milk.

Other Tips and Tricks about Storage

  • The contents of the milk tend to separate during storage so you will see different layers, make sure to swirl the bottle to mix everything back together before feeding the baby, that way the baby gets all the nutrients from the milk.
  • If the baby does not finish her bottle, it is alright put unused milk from the feeding back in the fridge and try to use it again within 2 hours. (if she does not drink it after that it is the best to get rid of the unused milk)
  • Throwing breast milk out can be heartbreaking, especially after working so hard, technically breast milk has not gone bad unless it has an odor. Babies will not drink milk that tastes bad, so they will not drink truly spoiled milk.
  • However, if you have gone past the recommended guidelines and do not want to chance it, you can always save the milk and use it for a milk bath for the baby, this will help give her super soft skin, and give the wasted milk another purpose so that you do not have to feel as bad about it. Just make sure to label the container for milk bath so you do not use it for a bottle.

Now Go Build up Your Freezer Stock!

I hope this post as answered all your questions about freezing and storing milk!

If you have any other questions, comments, or concerns feel free to leave them below or email me at I will respond as soon as possible!!

If you have any stories about your breast milk storage adventures, I would love to hear them, please share them in the comments section!!





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6 thoughts on “How to Freeze Breast Milk – Tips for Safe Storage”

  1. I wish I had known the above when I was breastfeeding! Awesome comprehensive info. Must read for all b/feeding moms.

  2. Great Article! I found it extremely informative. I have shared it with a friend of mine who just had a baby and is now breastfeeding. I liked all of your storing tips especially the timelines for how long the milk can be in the fridge and freezer.

  3. Thanks a lot for writing this. My girlfriend is having her first baby in a couple of months. There are ton of things we have to keep in mind. I’m a first time father and to be quite honest with you I am kind of scared. There is a lot of responsibility.

    This is a dumb question, but how long should a child be fed breast milk? I know you can freeze it in the freezer, but how old should the child be on breast milk.

    1. Hello Garen,
      First of all I would like to say congratulations on your expanding family, that is so exciting!!
      That is not a dumb question at all!! It is recommended by most pediatricians the American Academy of Pediatrics that a baby’s diet strictly consist of only breast milk or formula until 6 months of age. After that solid foods can be added to the diet. Babies should continue to drink breast milk or formula until at least 12 months of age. Ideally it is best to continue on breast milk until 2 years of age, if possible.
      There is nothing wrong with continuing the give breast milk past 2 years of age and extended breast feeding is actually encouraged in some cultures to until the age of 4 or 5. However, anything after 12 months of age is completely up to you, your family, and your pediatrician!
      I hope this answered your question! Well wishes to you and your family!!

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