How to Freeze Breast Milk: Common Mistakes and Must-Dos

One of the most common questions our lactation counselors are asked is regarding how to freeze breast milk. The most important thing to remember is that having a huge stash of frozen breast milk is not the be-all and end-all of breastfeeding. Number one is making sure your baby is fed in the moment. Then you can work on building a “stash” – whatever that looks like for you. We have some great tips for passively collecting milk to start building a stash (whether for the next feeding or to freeze) that can be found here.

How to Freeze Breast Milk

As I’m sure you’ve heard it is best to freeze breast milk in smaller quantities. The main reason for this is that frozen breast milk, once thawed, should be used within 24 hours of thawing. According to the Academy of Breastfeeding Medicine the “ability to inhibit bacterial growth is lessened, especially by 24 hours after thawing”. So how much milk should you freeze? Anywhere from 1 to 4 ounces is appropriate.

In what can I freeze my breast milk?

Using Milk Storage Bags

I’m sure everyone knows that there are a variety of companies who make breast milk storage bags. These are convenient for storing, freezing, and transporting breast milk. As far as favorite brand I personally prefer the Ameda Store N Pour Bags because they make transferring milk into a bottle simple. However, you can definitely cut the end off of the Medela or Lansinoh bags (or any of them, really).

Regardless of the brand, the ounce measurements are notoriously inaccurate on storage bags. So before you transfer milk from the bottle to the bag take note of the amount. Be sure to record the amount of milk you are storing and the date pumped. If you are storing milk from multiple days in one bag to freeze, the date should be that of the oldest milk in the group.

Wow! Look at how much less space the bag on the left will take up because it was frozen flat.

Another tip is to freeze your bags laying down so they are flat. This reduces the surface-area-to-volume ratio meaning that, not only will the milk freeze faster, but it will thaw more quickly, too. Another HUGE benefit of this is that these bags will take up less room in the freezer than if you froze them standing up.

Milkies makes a product called Freeze that will assist you in storing your bags of milk flat and help maintain “first in, first out” milk rotation. If your stash exceeds what this product holds you can use a storage organizer (like this one) for the overflow.

Storage Bag Alternative

There is a more eco-friendly option! A product that I recently came across that I LOVE is the Milkies Milk Tray. This freezes milk in 1 ounce sticks that you can then store, en masse, in a zip top bag or glass container in the freezer. When you’re ready to feed baby, simply pop however many 1 oz sticks you need into the bottle. It’s definitely a mess-free way to get bottles ready! What I also love about this product – you don’t need to worry about milk storage bags leaking when they are in the refrigerator. And, you can use this product when your little one starts eating solids to freeze purees that you make.

Other Things to Consider

When freezing your breast milk (or storing it in the refrigerator) you will want to make sure you are storing it in the freezer (or refrigerator). Do not store breast milk in the door. The temperature in the door does not remain as constant as on the shelves. When possible you want to avoid temperature fluctuations of expressed milk.

You do not need to stress over the time of day that you pump your milk. Some women will keep milk pumped in the morning after drinking coffee separate because of the caffeine that is transferred to the milk (and only feed it to the baby during the day). That is totally your prerogative.

Milk storage guidelines are always changing! The current recommendations, per the Academy of Breastfeeding Medicine are summarized here:

We can also send you a copy if you text MILK to 914-200-1707.

I’m not sure if I’m late to the game or if there are others who didn’t know this also, but: Amazon will tell you if items may be eligible for purchase with your FSA or HSA funds. How awesome is that??