Whether your building up a stash of breastmilk for a rainy day, or trying to stabilise your supply, or  preparing to return to work - we have summarised the key tips to follow for safely storing, defrosting and using your expressed breastmilk. 

How to freeze your breast milk?

Should you store breastmilk in the Fridge or Freezer? 

How you store your expressed milk depends on how soon you plan to use it.

  • If you are saving it to a rainy day or a few weeks down the line -  store it in a freezer.
  • If you are planning to use it within a few days, - store it in the refrigerator.

Overall, refrigerating is better than freezing, as freezing milk will mean that it loses some of the nutrients that fight infection. 

Best way to express and store breastmilk?

Whether you choose to refrigerate or freeze your milk, you should follow the best hygiene practices. Such as:

  • Use sterilised containers. Use for plastic bottles or plastic breastmilk bags. Glass bottles may crack or chip.
  • Label and date your bottles and bags, and use up the oldest ones first.
  • Keep your breast pump clean. Wash the parts in hot, soapy water, and rinse them thoroughly before sterilising.
  • Wash your hands before expressing and handling breastmilk for storage. Keeping everything as clean as possible will make it less likely that bacteria will grow in your stored milk.
  • If you want to freeze your milk, do it as soon after expressing as possible. Leave a gap at the top of each bottle or bag, as your milk will expand during freezing.


Common Questions

How do you defrost frozen breastmilk?
Frozen breastmilk should ideally be defrosted in the fridge, and can be stored there for 12 hours. It can also be defrosted in a jug surrounded by hot water. Never re-freeze breastmilk once it has thawed.

Even if you are in a rush, do not defrost or warm your breastmilk in a microwave. If you need the milk in a hurry, defrost it under cool, then warm, running water, or place it in a bowl of warm water. Dry the outside of the container before you open it, and use it straight away. Microwaving your breastmilk will decrease its nutrients and natural antibodies.  

 How long can you store breastmilk for?

  • in the fridge for up to 8 days at 4C or lower – if you're not sure of the temperature of your fridge, or it is higher than 4C, use it within 3 days of expressing
  • for 2 weeks in the ice compartment of a fridge
  • for up to 6 months in a freezer, if it's -18C or lower

Breast milk that's been cooled in the fridge can be carried in a cool bag with ice packs for up to 24 hours.

Can you can add freshly expressed milk to breastmilk that’s already in the fridge?

Yes, if it has been expressed on the same day and you leave it to cool it thoroughly in the fridge first before mixing the two batches. Bear in mind, that you can only keep it until the original milk is five days old.

There are two colours of my frozen milk. Is this normal? 

Yes. your milk has been stored for some time, you may notice that it separates between the creamier/fatty part and the watery part (hind milk and fore milk). This is normal, so just give it a gentle shake to mix it up again. Do not shake it aggressively like you would formula, as this may deplete some of its nutrients.