Practical Tips for Packing, Freezing, Re-Heating and Storing Breastmilk

Once you are accustomed to the basics of expressing breastmilk, you might want to look for new ways to make expressing a bigger part of your life and extend the convenience of this way of feeding your baby...

Maybe you love to breastfeed and know all the benefits of breastmilk, but want to go back to work, share the night feeds, or you just want a break from breastfeeding sometimes. Or perhaps you are a mum who is exclusively expressing whose baby for one reason or another cannot feed from the breast.

Maybe you are working and expressing so that your childminder can feed your little one during the day, and you have invested in a great Medela breast pump, but now you have so much extra milk you don’t know what to do with it.

It’s important to store your breastmilk the right way so you can preserve its nutrients and immunity-boosting benefits for your baby. Human milk actually has anti-bacterial properties that help it to stay fresh. You just have to store, freeze, and rewarm it properly.

Here are a few tips for how to pack, freeze, store and thaw breastmilk to give your baby an efficient source of nutrition and immunity, even when you’re not there to breastfeed:

Equipment You Will Need for Storing Breastmilk

Storing breastmilk may sound complicated – or even a little intimidating – at first. But, once you get the hang of it, it really is a simple process. Here’s what you will need to get started.

  • A great breast pump that fits your lifestyle.
  • A good size freezer.
  • Storage Containers, Option 1: Medela Breastmilk Bottles: These are made out of BPA-free polypropylene and are proven to be safe for babies. They work directly with Medela Calma feeding solution. Our breastmilk bottles are designed to store and protect your breastmilk through all the stages of refrigeration, freezing, and warming. They help to maintain breastmilk’s complex life enhancing beneficial nutritional properties.
  • Storage Containers, Option 2: Medela Pump and Save Bags: If you prefer not to use a bottle for storage, you can save space in your freezer by using a bag. Pump and Save bags take up less space than breastmilk bottles, and you can pump milk directly into the bag, preventing milk loss. The bags are pre-sterilized and ready to use with a double membrane to preserve and protect breastmilk’s beneficial nutrients during the freezing, refrigeration and warming process.

Tips for Storing Breastmilk

Medela offers extensive guidelines for storing breast milk at room temperature, in the refrigerator, or in the freezer. Our tips for storing breastmilk include:

  • Wash your hands before touching bottles and bags, and avoid touching the interior of bottles or caps.
  • Pump or express your breastmilk into clean bottles or bags. If using Pump & Save bags, always use a new bag for each pumping session.
  • To avoid waste, store milk in small portions by putting only 60 to 120 ml (two to four ounces) of milk in the container (that’s the amount your baby is likely to eat in a single feeding).
  • Fill the container up to 3/4 only. Milk will expand when freezing.
  • Squeeze out the air at the top of the milk bag before sealing. Disposable bottle liners or plastic bags are not recommended because with these, the risk of contamination is greater.
  • Mark the collection date on the storage container.
  • Include your baby’s name on the label if your baby is in daycare.
  • Check out these Breastmilk Storage and Handling Guidelines for more information.

How to Freeze Breastmilk

Breastmilk can be safely frozen and stored for up to 12 months, but it requires special handling:

  • Breastmilk should be stored and frozen in small amounts of 60ml to 120ml per bottle or bag. The reason for this is that it takes less time for smaller amounts to thaw, and also this is close to the typical amount that babies consume at each feeding session.
  • When freezing breastmilk, be sure to leave some space in the container for the liquid to expand – you should only fill the bottles up to ¾ full, and do not fill bags with more than 150 ml of breastmilk.
  • Cool the breastmilk before putting it in the freezer, and never refreeze breast milk once it has been thawed.
  • If you want to refrigerate breast milk for several days or freeze it, it’s important to seal the bottles tightly and use solid lids.
  • Put breastmilk inside the main compartment of the refrigerator at the bottom– do not store it in the door of the refrigerator, since the temperature there can be less consistent.
  • The needs of babies change over time. Therefore breastmilk is ever changing and its composition changes with the age of the baby. Therefore it makes sense to use frozen breastmilk within 3 months in order to match the baby’s needs.

Tips for Thawing Breastmilk

Thawing breast milk requires careful attention and following a step-by-step process – you want to make sure the breastmilk is at the right temperature for your baby to consume:

  • Thawing with water: Place the frozen breastmilk (in its sealed container) into a bowl of cool water, or hold it under a faucet of cool running water. You can use this process to thaw the frozen milk until it is melted or in a liquid state, but still cold – then simply dry off the bottle with a towel, and put the cold liquid breastmilk in the refrigerator until ready to feed your baby. Run the breastmilk under warm water before feeding your baby – but make sure the temperature is not above 37°C.
  • Thawing breast milk in the refrigerator: Simply put the frozen breastmilk in the refrigerator and leave it there overnight. Once it is thawed the next day, swish the container around to re-mix any fats that separated overnight during storage.
  • Once you have thawed the breastmilk, you can feed the thawed milk to the baby immediately, or store it in the refrigerator for up to 24 hours.
  • You can also use thawed breastmilk away from home. If you are on holiday or bringing breastmilk with you to another location, bring a cooler full of ice packs to help keep the breastmilk cool.

Safety Tips for Thawing and Rewarming Breastmilk

There is nothing dangerous about thawing and rewarming breastmilk, as long as you follow a few simple guidelines.

  • Never use a microwave or boiling water to thaw or warm breastmilk. The reason for this is that high temperatures will damage the breastmilk’s essential nutrients. Also, microwaved breast milk can cause the milk to heat unevenly throughout, creating “hot spots” that are dangerous to the baby.
  • Do not let thawed breastmilk sit out at room temperature.
  • Do not refrigerate warmed breastmilk. Any milk that the baby does not consume should be discarded.

Once you get into the expressing flow (pun intended) you will find that expressing, storing and using milk gets much easier.

Do you freeze and thaw breastmilk for your baby? Which methods of storage and freezing have worked best for you? Please leave a comment to share your thoughts, or join the discussion on the Medela Australia Facebook page.