Medela Tips for Pumping Breastmilk - Packing, Freezing, Storing and Re-heating

You love to breastfeed and know all the benefits of breastmilk, but want to take a break from breastfeeding sometimes. Or perhaps you are an exclusive breast pumping mom whose baby for one reason or another cannot feed on the breast.

You will or have invested in a good quality breast pump, providing you extract milk. 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:
  • A great breast pump that fits your lifestyle.
  • A good size freezer.
  • Breastmilk Bottles or Bags (bags for breastmilk are an economical option and save space in your freezer. They are pre-sterilized, ready to use and are made with a double membrane to preserve and protect breastmilk’s beneficial nutrients.

There are extensive guidelines for storing breast milk.  Here are the principal ones:

  • Wash your hands before touching bottles and bags, and avoid touching the interior of bottles, caps and, bags.
  • Pump or express your breastmilk into clean bottles or bags.
  • To avoid waste, store milk in small portions by putting only 60 to 120 ml of milk in the container (similar quantity of a breastfeeding session).
  • Fill the container up to ¾ 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.

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. It takes less time for smaller amounts to thaw, and also it is a similar quantity of a breastfeeding session.
  • 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 or bags are sealed properly.
  • Put breastmilk inside the main compartment of the freezer–not store it in the door, since the temperature there can be less consistent.
  • The needs of babies change over time so composition of breast milk changes with the age of the baby. Therefore it makes sense to use frozen breastmilk within 3 months.

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:

  • 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 until it is melted/in a liquid state, but still cold –put the cold liquid breastmilk in the refrigerator until ready to feed your baby.
  • In the refrigerator: Put the frozen breastmilk in the refrigerator.  Once it is thawed, 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.
  • Run the breastmilk under warm water before feeding your baby – but make sure the temperature is not above 37°C.
  • You can carry thawed breastmilk away from home with a cooler full of ice packs to help keep the breastmilk cool.
Safety Tips for Thawing and Rewarming Breastmilk:
  • Never use a microwave or boiling water to thaw or warm breastmilk. High temperatures will damage the breastmilk’s essential nutrients and 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 breast pumping flow (pun intended) you will find that having a good supply of fresh breastmilk can open up a new more relaxed lifestyle, giving you more time to do other activities with your baby or for yourself. You might even get to drink a cup of coffee when it is still hot!


Medela offers breastfeeding accessories and breast pumps to mothers in Quebec and around the world. A long-time champion of breastfeeding, Medela is the only company to develop products based on the latest research by leading breastfeeding experts and feedback from breastfeeding mothers. As a result, Medela pumps are the number one choice for healthcare professionals, healthcare facilities and mothers around the world. Only you can provide what’s best for your baby. Medela can help.

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