How to Safely Use Thawed Breast Milk

Article By
Sonni-Ann
Published On
23 May, 2023
Read Time
3 minutes

Storing some breast milk in the freezer can be really useful. But if you're new to expressing and storing breast milk you may be wondering how best to defrost it, and you're not alone. This is one of many questions that new parents have about feeding their baby.

To help you out, we're going to run through how to safely thaw frozen breast milk and cover some top breast milk storage tips to save you both time and effort.

Different methods for defrosting breast milk

In the refrigerator

You can gradually defrost frozen breast milk in the refrigerator.

In a bowl of warm water

You can defrost frozen breast milk that's in a sealed container by putting it in a jug of warm water.

Under running warm water

Alternatively, you can run warm water at a maximum temperature of 98.6°F over a bottle or bag of frozen breast milk.

How long to defrost breast milk

The amount of time that breast milk takes to defrost depends on which method you choose:

  • In the refrigerator: This is the best method, but it can take breast milk up to 12 hours to defrost in the fridge. So, it's recommended you get out what you need for the next day the night before to give it time to thaw overnight.
  • In a bowl of warm water: This breast milk thawing method should take around 20 minutes.
  • Under warm running water: This method takes around five to 10 minutes, but it's not the most eco- or wallet-friendly option.

How long does defrosted breast milk last?

Once fully thawed, defrosted breast milk that was previously frozen can be kept at room temperature for up to two hours or stored in the refrigerator for up to 24 hours.

Safety advice for thawed breast milk

  • You should never defrost or warm breast milk in the microwave. This can heat it unevenly, potentially leading to burns. It can also destroy the nutrients in your milk.
  • Throw away any leftover thawed milk after 24 hours.
  • You should never leave frozen breast milk to defrost at room temperature.
  • Never re-freeze defrosted breast milk.

Tips for using frozen breast milk with minimal waste

We know that pumping, freezing, and defrosting breast milk is a lot to think about! The following tips may help simplify the process and reduce the risk of any of your precious breast milk being wasted.

Start with the oldest milk

When getting milk out of storage to feed your baby, use a first-in, first-out approach. It can help to label your expressed milk with the date it was pumped before you store it in the freezer. That way, you know you're always using the oldest milk first. 

Use storage bags

Our pre-sterilized breast milk storage bags are made for breast milk, and help it thaw faster.

Freeze milk in ice cube trays

Most ice cube trays have individual sections that hold around 1oz each. These can be handy for measuring out the right amount of breast milk needed for each feed.

How do you defrost breast milk quickly?

Slowly defrosting breast milk in the fridge is best. But if you need to thaw frozen breast milk fast, you can defrost it in a jug of warm water or run it under running warm water.

If it's been defrosted in the refrigerator, breast milk should be used within 24 hours. You should start counting the time when the milk is completely thawed and not from when you first put it in the refrigerator.

Yes, babies can have cold breast milk. But if your little one prefers their feed warmed slightly, you can warm it up once it's defrosted by: 

  • Placing the bottle in a fresh warm jug of water.
  • Running under the warm tap.
  • Using a specially designed bottle warmer.

Test the temperature of the milk before feeding it to your baby. You can do this by placing a drop on your wrist or the back of your hand. The milk should feel warm, not hot.

Breast milk shouldn't be reheatedif your baby doesn't finish their feed. So, it's best to only warm a small amount at a time.

Breast milk that's been frozen and then thawed can sometimes smell different from fresh breast milk - some parents say it smells like soap or has a slightly metallic taste. This is because of the release of fatty acids but won't cause any harm. Don't worry, if you've followed the guidelines we've covered above, your thawed breast milk will be safe to give to your baby.