Breast Milk Storage Guidelines – Tips and More!

breast-milk- storage-guidelines

If you haven’t ever cried over spilled milk, then you are probably not a pumping mom…

There is a reason breast milk is often referred to as, “Liquid Gold.” It takes hard work, sweat, and tears to build a breastmilk stash. It is NOT easy!

So once you start building up those ounces, what do you do with them?

How long is breast milk good in the refrigerator? How long can you keep it at room temperature?

How long is it good in the freezer? Can breast milk be reused?

These are common questions asked by many breastfeeding and pumping moms.

Well, here at The Pumping Mommy, we have you covered! Here are the answers to those questions and more!

breast-milk- storage-guidelines

Breast Milk Storage Guidelines – Tips and More!

Breast Milk Freezer and Refrigerator Storage

**NOTE: Please consult with your Doctor regarding storage guidelines if your baby was premature as those guidelines can differ or if your baby has any special health needs. These guidelines are to be applied to a healthy, full-term baby.** 

Freshly Expressed Breast Milk – 

  • Room Temperature – Discard after 4-6 hours
  • Cooler with Ice Packs – Discard after 24 hours

Refrigerated Breast Milk – 

  • Freshly Expressed Milk – discard after 3-8 days (ideally, 3 days. This will depend on the temperature)
  • Thawed Frozen Milk –  discard after 24 hours

Frozen Breast Milk –

  • Standard refrigerator attached freezer – discard after 6 months
  • Deep- freeze, stand-alone freezer  – discard after 12 months

8 Breast Milk Storage Tips

1 – Avoid Waste

Avoid wasting breast milk by storing in smaller quantities like 1-4 oz.

2 – Use an Ice Cube Tray

Many companies make breast milk storage bags, but you can also freeze in an ice cube tray.

Each cube should be about 1 ounce for a standard ice cube tray. Just ensure it is sterilized and properly covered while freezing. Then pop the frozen breast milk cubes into a freezer zip lock bag. (This tip can be applied to freezing homemade baby food too!)

Or try Milkies Trays! If you use standard neck size bottles (not wide neck), then an ice cube won’t fit. Milkies Trays are the perfect size for all bottles! The freeze the milk in a long stick shape. Perfect for slipping into a bottle!

breast-milk- storage-guidelines

Milkies Milk Trays

3 – Leave Room at the Top

If you use the breast milk storage bags, leave some room at the top as frozen milk will expand and you don’t want your bag to tear!

(It’s good practice to look at a bag first too before thawing to make sure there are no holes or your milk will leak out as it thaws!)

It is best to store in smaller quantities like 4 ounces each bag. Do not store more than your baby will eat in one feeding. Once you thaw/heat the milk, you cannot restore it. You must discard any milk your baby does not take.

4 – Store Milk in the Back

Always store breast milk at the BACK of the refrigerator or freezer to ensure limited change in temperature when you open and close the doors.

5 – Keep it in Order

It is important to follow the guidelines for breast milk storage, so make sure to date each bag or bottle of milk so you know when it will expire.

It helps to have a storage bin in the freezer or refrigerator to keep the milk in order so you can always be sure you use the oldest milk first when feeding your baby.

A cheap and simple solution is a tray like the First Years Storage Tray. It fits perfectly in your freezer or refrigerator. (Make sure you freeze you bags laying flat, however. Don’t freeze them in the storage container)

breast-milk- storage-guidelines

First Years Milk Storage Tray

6 – Do NOT add Warm Milk to Cooled Milk

Do not add warm milk to cold milk! Cool the milk first before adding to already cold milk.

You can combine milk from various days (as long as it’s not expired) but you need to use the date of the oldest milk as the expiration date. 

7 – Swirl, Don’t Shake

Note that stored breast milk will separate into layers.

The “cream” rises to the top while the bottom looks more watery. Expressed breast milk will also vary in color, smell, and consistency, so do not be alarmed.

Make sure you swirl the breastmilk to “mix” it. Do not shake it.

8 – Rule for Offering Milk Twice:

If baby does not finish an entire bottle, studies show it is probably safe to refrigerate for 1-2 hours before offering it again or discarding it.

But there are factors that should be considered such as if baby sick (more bacteria will be introduced to remaining milk) or how long the milk was out, to begin with, etc.

Looking for Breast Milk Storage Bottles? Check out our Breast Pump Parts page!

How to Thaw Frozen Breast Milk

It is best to thaw frozen breast milk slowly. Put frozen milk in the refrigerator overnight.

Do not thaw by letting the milk sit out at room temperature.

For a faster method, hold bag or container of frozen milk under cool running water.

Then either heat the milk using the methods list below (in How to Warm Breast Milk) or refrigerate.


  • NEVER microwave breast milk! It will create hot pockets of scalding milk that will burn baby. 
  • Thawed breast milk is good for 24 hours in the refrigerator.
  • You CANNOT refreeze thawed breast milk.

How to Warm Breast Milk

To warm Breast Milk for your baby:

Use a bottle warmer or place the container or bag of milk (thawed or frozen) into a cup of warm water. 

Let sit in the warm water until it is the desired temperature.

Never use HOT water as it can cause the temperature of the milk to be too hot for baby and burn her.

Test temperature on the underside of your wrist to ensure it is safe.

  • Breast Milk temperature to feed baby should be about body temperature (98.6 degrees). It will feel luke-warm and should NEVER feel HOT.

Again, NEVER microwave milk or heat directly on the stove. You can burn baby!

Have any helpful tips on breast milk storage? Leave your comment here!

Want to build a Breast Milk Freezer Stash? Not sure where to start? Start right, here!! Click here to find out how to pump enough to fill your freezer today.

Related Articles – 


Read: Need a Sample Breast Pumping Schedule? Get that Here!

How Much Breast Milk Does Baby Need

How Much Breast Milk Does Baby Need


Read: Love Avent Bottles? Get Yours Here!


  1. Paola says:

    I was wondering can I pump throughout the day, store in the refrigerator, and then at the end of the day freeze my breast milk?

    • Heather Grace says:

      Hi Paola!

      Yes, you can pump throughout the day and then freeze. There are a few things to consider:
      1) You CANNOT add warm breast milk to cooled breast milk. Best tip, if you want to combine milk from different pump sessions, is to first cool the breast milk you just pumped and once cooled (after a few hours), you can add it to milk you pumped previously.

      2) You CANNOT add refrigerated breast milk to already frozen breast milk. You need to freeze the new milk separately.

      3) Any time you are combining breast milk from different sessions, you will want to use the oldest date as the date to go by for expiration. (though if you are only combing that days pumped milk, then this will be a non-issue).

      Hope this helps!

  2. Kylina @bootiesandthebeast says:

    I love the idea of using a ice trays! This is a great way to save space too if you don’t have storage bags. Thanks!

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