Managing Your Freezer Stash

Freezer Stash- n. Collection of surplus breastmilk frozen for later use. Whether you are considering starting up a freezer stash or looking for advice on how to use yours, this post is for you! You might be wondering why it might be beneficial to freeze milk, how best to store it, when and how to begin using it, and how to figure out how long it’ll last! All this and more is coming your way. Read on, momma!
*Trigger warning- This blog post contains images and descriptions of large breastmilk freezer stashes. If this troubles you, please close out of this blog post.*

Disclaimers: This post contains affiliate links and codes from trusted brands. All images in this post were either donated with permission or taken by me.

Do I need a freezer stash?

There’s no cut-and-dry answer for this.

Many mommas who predominately nurse baby at the breast do not choose or need to store extra milk. It may be wise, however, to save a few day’s worth of ounces in the freezer (breastmilk fed babies can take up to 30 ounces a day) in case of emergencies. One momma I worked with was admitted into the hospital with appendicitis without warning and was glad she had a bit of milk stored up! Saving a bit of milk can also come in handy if you’re planning to be apart from baby. If you are planning to be separated from baby over the time you’d nurse, you’ll need to leave milk for the baby, and pump at the time you’d normally nurse.

For exclusive pumpers with oversupply, it’s wise to keep a day or two ahead in the refrigerator, and freeze the rest. This milk can be fed when you begin to wean and extend the time you are able to offer breastmilk. Some mommas choose to donate their extra frozen milk formally (milk bank) or informally (mother-to-mother, directly.)

Mommas who supplement with formula can offer partial breastmilk and partial formula, and freeze the rest. This can actually help exclusive pumpers reduce the number of times they pump daily and have proven to pump for longer than they originally planned because their schedule becomes more manageable. A partial diet of breastmilk is still hugely beneficial to your baby, offering white blood cells and antibodies in addition to daily nutritional benefits.

My personal stash story:

With my first baby, I set a goal to exclusively pump for six months. When I hit the six month mark, I began to reduce my pumping schedule to gain a bit more freedom, and began supplementing with formula. Since my son was starting many other foods at this age, supplementing was not a huge mental hurdle for me- I grouped formula in with all the other foods nurturing my baby that I did not personally make. (You don’t give yourself a hard time for not producing pureed yams and apples with your breasts, right? Just group formula in with other additional nutrition!) I switched to 50/50 breastmilk and formula. I stashed my extra milk in the freezer and was able to not only surpass my original pumping goal, but to offer breastmilk longer than I imagined!
With my second baby, who I also exclusively pumped for, I created an unintentional freezer stash because she was having trouble digesting my milk in addition to a milk protein allergy. I donated 1,000 ounces of frozen breastmilk that contained dairy to another baby. When we discovered that she was digesting my milk comfortably with a 50/50 breastmilk-formula ratio, I was able to stash extra breastmilk and once again feed greater freedom with my pumping schedule and offer breastmilk longer than I imagined.

Check for high lipase!

Lipase is an enzyme found in all breastmilk that helps break down fats. It’s a good thing! But some women struggle with high levels of this enzyme, causing their milk to smell or taste funny. You usually won’t notice the smell until you defrost your milk after freezing. High lipase can cause your milk to smell soapy or metallic. (Breastmilk without high levels of lipase usually has a mild smell or no smell at all, and slightly sweet taste.) High lipase milk is ok for baby to drink, but they may not want to. I strongly encourage you to TEST EARLY for high lipase before stashing away a ton of milk! Freeze and defrost milk early to test this out. How do you “test” your milk? Just thaw some breastmilk and give it to your baby! If baby takes it, no problem! If not, you’ll have to scald your milk BEFORE feeding or try one of the tricks listed in my blog post on high lipase.

How do I store all this milk?

Storing breastmilk in “bricks” can really help freezer space and organization…AND flat bags thaw quicker! I stored 5 ounces of milk per bag, removed as much of the excess air as possible, frozen flat on a tray, and then assembled into bricks of 50 ounces in gallon-size ziplock bags. When freezing super flat using a “freese-it-flat” or between boxes of fish sticks like me, you get reallllly flat bags capable of stacking together nicely in gallon ziplocks! This uniformity makes it very easy to stack and count. Check the image below and the storage page of my website for more information on the logistics of milk storage.

I highly suggest freezing in breastmilk storage bags instead of bottles. More and more companies are making silicone freezer bags as a reusable option. (Save on Junobie brand with code PUMPMOMMA10) Some mommas store smaller quantities of milk in silicone trays and then once frozen, transfer to larger storage containers. (Save on SouperCubes with code PUMPMOMMAPUMP10)

Many mommas end up buying a chest freezer for their breastmilk. I recently helped a friend stock their 5 cubic foot chest freezer with approximately 2,000 ounces of breastmilk. If you are a massive overproducer, you might need a larger chest freezer. We personally purchased a 3.5cu feet smaller model chest freezer and still call it the “milk freezer” to this date (even though it’s now full of chicken nuggets instead of breastmilk!)

How long will it last in the freezer?

Breastmilk is good for up to 12 months in the freezer. The CDC used to specify different lengths of time for different types of freezers. They changed their recommendations to “best by 6 months, good up to 12 months” regardless of freezer style.

First in, First out!

When it’s time to begin using your stash, think “First in, First out!” Make sure to rotate your freezer stash by feeding the oldest milk first, and freezing new milk. When doing the “brick method” as described above, write the MONTH really large on the sides/top of the brick- this way, you can immediately know what milk to pull from the freezer! (You can write a date range if you are really organized, but I find that the month is good enough.)

How do I begin using my stash?

This part is up to you! Here are a few ideas of how I’ve seen mommas use their freezer stash.

• BOTTLE-A-DAY – Give one bottle of frozen breastmilk per day
• FREEZER FRIDAYS – Choose one day of the week to use frozen milk
• DAYCARE – Use frozen breastmilk on daycare days
• SUPPLEMENT – Go 50/50 with thawed breastmilk and formula, either half bottles of breastmilk and
• MIX IT UP- Combine frozen and fresh breastmilk in feeding bottles *must be used within 24 hrs of final thaw
• DONATE – Consider donating excess breastmilk formally (through a milk bank) or informally (direct mother-to-mother donation)
• EXTEND THE END – Extend the time your baby receives breastmilk by continuing to feed frozen milk after you have weaned from fresh milk production.

For more info on introducing a bottle after exclusively nursing, visit my blog post on the topic.

Safely combining frozen milk with fresh breastmilk or formula

It’s completely fine to combine your frozen breastmilk with freshly expressed breastmilk or formula as long as you do it safely. It’s a wise idea to make sure your baby takes frozen milk first, so you do not waste whatever you mix it with. For mommas with high lipase, mixing it with fresh milk or formula may disguise the stronger flavor of the thawed milk!

When mixing thawed breastmilk with freshly expressed milk, temperatures don’t matter as long as you are feeding it to baby right away. You can even thaw larger amounts and combine with fresh in a pitcher, as long as you use this combined milk within 24 hours of complete thaw (going by recommendations for thawed milk here instead of fresh!)

When mixing thawed breastmilk with formula, prepare formula as directed first, then add thawed breastmilk. Use within 24 hours after mixing. *DO NOT use breastmilk as a replacement for water when preparing powdered formula!* Breastmilk can actually help your baby digest the formula!

Can I feed my older baby milk from when they were younger?

Absolutely! They will most likely need the same amount, or a tiny bit more, than they current drink. I suggest offering the amount you are used to offering, and heating up more if needed, so you do not waste milk. The only word of caution I have about this comes to colostrum. That thick yellow milk from the first few days after birth is still hugely beneficial to your baby, but may act as a bit of a laxitive if given in concentration, so I suggest diluting it in more mature milk. You can even give an older child your baby’s frozen milk! Some people use it in cereals, smoothies, or sippy cups!

How long will my stash last?

Here’s where you’ve got to do a bit of math. Take the amount of ounces you froze and divide it by the number of ounces your baby drinks per day. (Example- 1000 ounces divided by 30 oz/day = 33 days of milk.) Most breastmilk-fed babies continue to take the same daily total ounces until they are 12 months old, when most pediatricians suggest increasing solid meals and reducing milk to ~16oz/day.

What about a power outage?

The thought of losing an entire freezer stash is horrifying, isn’t it? I highly suggest equipping your chest freezer with a freezer alarm (they even make wifi freezer alarms now!), and taking the necessary precautions for impending outages. I have an entire blog post on what to do if your power goes out, so be sure to bookmark it incase your house experiences a power outage (especially during hurricane or winter storm seasons!)