The New Mom’s Guide on How to Store Breast Milk



If you’re like a lot of moms, you’ll be headed back to work after a few weeks of being at home with your baby. You may have mastered pumping on the go, whether at work, on an airplane or in a car, but if you don’t know how to store breast milk properly, the liquid gold you worked so hard for could be a waste.


The first thing is to make sure that you have a reliable breast pump. My favorite breast pump that I have used is the Spectra S1. I had tried another brand prior to using the Spectra but I didn’t feel like I was getting enough milk.


I wanted to create a new mom’s guide on how to store breast milk answering all of the questions I had when I was a new mom who was pumping and headed back to work. It’s important to know from the beginning of your pumping experience the in’s and out’s associated with pumping and storing breast milk.


*This post may contain affiliate links, which means I receive a small commission, at no extra cost to you, if you make a purchase using this link. I only recommend products I love or would personally use.


breast milk storage bags


How to store breast milk?

The best way to store breast milk really depends on the circumstance. If you plan to use the breastmilk within 6-8 hours, you can typically leave the breast milk to sit out. If it is going to be longer than 6-8 hours, you can place the expressed breast milk in a bottle or a breast milk storage bag and place it in the refrigerator.


When breast milk is properly stored in the refrigerator, it will keep for 3-5 days. If you won’t need the milk within those 3-5 days, you’ll need to store the breast milk in the freezer. The best way to do that is in breast milk freezer bags. Properly stored breast milk can be kept in the freezer for 6-12 months.



How to use breast milk storage bags?

The first thing you need to know about storing breast milk in bags is that you need to use plastic bags that are designed specifically for breast milk. You don’t want to use the same type of bag you’d use to give your kiddo a bag of snacks. You’ll end up with spilled milk and likely a big mess.


Figuring out how to use breast milk storage bags will depend on the kind of bags you plan to use. Some breast milk storage bags connect right to the breast pump, while most others do not. If your storage bag connects right to the breast pump, there should be small holes in the top of the bag where the bag will connect to the pump. You’ll open the bag, place the pump piece down into the bag, pull the bag up around the pump part, and then hook the bag to the pump part.


breast milk freezer bags




What to do if your bags aren’t designed to connect to a breast pump?

If your breast milk storage bags are not designed to connect right to the breast pump, that’s not a big deal. All you’ll need to do it take your expressed breast milk that is likely in a bottle, open the breast milk storage bag, and carefully dump the milk into the bag. I always liked to squeeze the zip seal part of the bag because it was the sturdiest part and I knew I had control of the bag, so it wouldn’t slip out of my hand and spill the milk.


Once you have placed the correct amount in the bag, you’ll want to carefully remove as much air from the bag as you can by holding the edges of the zip seal, using the other hand to gently squeeze the bad, and then quickly seal the bag up.


Either before or after you do this, you’ll want to make sure you label the bag. Usually, there is a place for you to write your baby’s name, the date, the time, and the volume.


Then you’ll want to lay the milk flat in the freezer. Once the milk is frozen, you can place the milk in the freezer wherever you want to store it long term, preferably not the freezer door.



Why do I need to record the time the milk was pumped?

It is important that you write the time of day when you pumped the milk because of your milk composition changing throughout the day. In fact, your breast milk will provide your baby with melatonin, which aids in sleep. Babies do not produce melatonin at such a young age, so breast milk pumped in the evening is best given in the evenings. How awesome and incredible is that?



How much milk should I put in a breast milk freezer bag?

This is a great question! You’ll want to store the approximate amount of breast milk your baby takes for a feeding. If you are just starting to build your freezer stash, a typical recommendation is usually 2-4 ounces per bag or bottle. From my personal experience, I would store about 2-3 ounces per container.



What are the best reusable breast milk storage containers?

If you want reusable breast milk storage containers, you have two options. You can invest in the Kiinde Twist breast milk storage bags or the Tommee Tippee Pump and Go Bags, which are washable and reusable. In fact, you can buy a piece that will connect to your breast pump and the milk will go right into the bag.


The bags can be stored in the refrigerator and freezer. They can be washed as re-used as often as you need to. Another bonus of these systems is that they have bottles specifically made for the bags. So, you can take a bag out of the refrigerator, warm it up, and connect the bag inside the bottle.


The other reusable breast milk storage containers and baby bottles that are freezer safe. You can use either glass or plastic bottles. One thing you’ll want to make sure that the bottles you’re using are safe to store in the freezer. Another thing to note any time you’re storing breast milk is to leave about an inch of space at the top of your storage container because the milk will expand as it freezes.


breast milk storage bottles


What are the best options for eco-friendly breast milk storage?

If you want to store your expressed breast milk in bottles, the eco-friendliest storage option would be glass bottles. A lot of people will tend to shy away from the plastic bottles if wanting bottles that are both eco-friendly and “green”. You can also use silicone molds to store your breast milk in the freezer as well. My best advice here would be to make sure that you have bottles with a wide enough neck that you’ll be able to place the frozen breast milk cubes down in them to thaw.



Best Breast Milk Storage Bottles


  1. Ameda Breast Milk Storage Bottles

Ameda breast milk storage bottles are great for pumping and storing your breast milk. One great thing about using bottles is that you eliminate the waste associated with using plastic storage bags. They are a two-piece set consisting of a bottle and lid. They are dishwasher and freezer safe. The bottles are made of plastic that is BPA and DEHP free. The bottles can hold up to 4 ounces of milk.



  1. Lifefactory Glass Baby Bottles

If plastic isn’t your thing, then the Lifefactory Glass Baby Bottles are a good alternative for you. They come in both 4 and 9-ounce sizes and they have a silicone plastic covering. They are made with a thermal shock-resistant borosilicate glass body, which makes them easily transferable from freezer to warm water for thawing if you have to.



  1. Evenflo Breast Milk Collection Bottles

The Evenflo collection bottles are a plastic bottle that is designed to hold 5 ounces of milk. They come with a plastic bottle and a 2-piece lid for storage. You can place the bottles in the freezer for storage just like the plastic storage bags. There is an adaptor that you can use with your breast pump to be able to pump right into the bottles. Then you can place a bottle top with nipple right to the bottle for easy feeding.



  1. Lansinoh Breastmilk Storage Bottles

These bottles are freezer and dishwasher safe, which is awesome for busy moms. You can pump directly into the bottles with a Lansinoh breast pump or with the Lansinoh breast pump adaptor. You can attach a Lansinoh nipple right to the bottle which is an added level of convenience. The bottles come with a cap for easy storage.



  1. Medela Plastic Breastmilk Bottles

The Medela plastic bottles are the bottles I used the most when I was pumping at work. The biggest reason I used these bottles compared to any of the others was that I was given a LOT of them. They worked for what I needed, so I kept using them. I shared about my experiences pumping on the go, and one of the great things about these bottles is that you can pump directly into them if using a Medela pump, or you can get an adaptor for your breast pump. They are the best breast milk storage bottles for going back and forth between work and home and they can be placed in the freezer. You can also put a Medela nipple on the top and give your baby a bottle.





Best Breast Milk Storage Bags


  1. Lansinoh Breast Milk Storage Bags

Lansinoh brand breast milk freezer bags are by far the best breast milk storage bags in my opinion! I think they were the easiest to open and use out of all the bags I tried. I don’t like bags that are too stiff or too flimsy. If you are wanting to pump directly into a bag, you can do that if using a Lansinoh pump, or you can get an adaptor for your breast pump. They are easy to fill, they don’t leak, and they are easy to freeze and thaw. I had no issue with them!



  1. Target Up and Up Breast Milk Storage Bags

I have tried a lot of breast milk storage bags, and Target was actually one of my favorite brands. It is funny to me because if you search for the best breast milk storage bags, these never pop up. That made me wonder if the people writing the reviews ever actually did any of their own trials. I like that the Target brand bags are cheaper than most brands, yet offer the same quality. If you’re looking for a great bag at a reduced cost, try these!



  1. Kiinde Twist

The Kiinde system is a great system available for nursing/pumping moms. They have developed an all in one system from the pumping of the breast milk all the way to consumption with just the use of the bag. You can pump directly into the bags, freeze or refrigerate the milk, and then use the bottle adaptor to give the baby a bottle using the very same bag. The level of convenience that comes with this system is barred none. You can use either the 6 ounce or 8-ounce bags depending on how much you want to store at one time. Also, they are one of the few reusable breast milk storage bags available. You can wash and reuse the bags which is another added bonus.



  1. Tommee Tippee Pump and Go Milk Storage Bags

Much like the Kiinde system, Tommee Tippee has an all in one system as well. You can pump into the bags using an adaptor and then take the bagged milk, attach a bottle top, and give the baby the milk. This is seriously a game changer for anyone who is super busy and wants to eliminate a step or two. Tommee Tippee also has a bottle warmer that is designed specifically for their breast milk storage bags.



  1. Medela Pump and Save

The Medela Pump and Save bags are highly respected as well because of their user-friendliness. You can attach the bag right to the breast pump without the hassle of transferring the milk from a bottle to the bag. If you are pumping on the go, and need to be quick and convenient, this is a great option for you. There is an area for you to write on the bag, they are self-standing, and they come in a pouch which is nice because that way they aren’t all over the place. The bags have a 6-ounce capacity.



  1. NUK Seal ‘n Go

The NUK Seal ‘n Go bags are designed to hold up to 6 ounces, though I have heard of people putting up to 7 ounces in them with no issue. NUK breast milk storage bags are much like several of the other bags, in that they have a stand-alone design, they can be placed in the freezer or refrigerator, and they have a double seal with a leak-proof guarantee.



  1. Ameda Store ‘n Pour

Ameda store and pour bags are awesome if you are using an Ameda breast pump. Much like the Kiinde system, as well as the Medela Pump ‘n Save, you can pump directly into the pour and store bags without the extra step of needing to pour the expressed milk into the bag. The bags are easy to label and store in your freezer. These bags have a really nice, unique feature, which is the tear-and-pour spout. There is a place on the side of the bag that you can tear off and easily pour the milk out of the bag without spilling. The bags are also designed so that they can stand on their own. They are DEHP and BPA free. They are labeled for 5 ounces of milk, but many people recommend putting no more than 4 ounces of milk in them.



  1. Mommy’s Precious

These bags make a big promise of no leakage. They also claim that their measurement labels are 95% accurate. The bags are labeled to store up to 8 ounces of breast milk. The bags are also designed to sit up on their own and lay flat for freezing. Unlike most brands who offer bags in a set of 100, Mommy’s Precious offers a package of 110. For me, the best part is that they have a 100% satisfaction guarantee.



  1. Nurture Right Breast Milk Storage Bags

Nurture Right bags come pre-sterilized, meaning that there is a seal on the bag that you will remove before putting milk in the bag. Most brands offer this to ensure that the bag has not been compromised prior to putting milk in the bag. The bags are leak-proof and durable. They also lay flat for freezer storage and provide a place for you to label your bag. Another great benefit is that you can store up to 6 ounces of milk in them, and they are easy to get the air out of and seal.



  1. Dr. Brown’s Breastmilk Storage Bags

I have not personally used this brand of breast milk storage bags, but based on reviews, they’re like several of the other brands of bags. The bags are designed to hold breast milk and they can be placed in the freezer or refrigerator. They are sealed prior to you placing milk in them to guarantee sterilization.  They are labeled to hold up to 6 ounces of breastmilk. People rave about them because they fit perfectly into a bottle warmer. If that’s a key factor for you, then these may be the storage bags for you!


  1. Philips AVENT Breast Milk Storage Bags

There is a lot of back and forth about a variety of factors associated with these bags. Some claim that they are very durable, and others say they are. Some say they leak and others claim no leakage. It’s a tough one to call with this brand of storage bags. It seems to me that either you love them, or you don’t. One thing that is really appealing to me about these bags is that they do seem to have a wider opening at the top, and they have a very large area for labeling. So, if you’re going to be transporting milk back and forth between home and daycare, these may be a great option for you to try!



  1. Milkies Durable & Leak-proof Breast Milk Storage Bags

The Milkies brand of bags offers something many other brands do not. The bags are made with a reinforced double layer, double zip plastic design. They are made from the highest quality food-grade plastic available, which I know can be a very important factor for some people. They hold a little more than 6.5 ounces. Another great thing about these bags is that the breast milk storage guidelines are printed right on the bag, which is amazingly convenient!





How long is breast milk good for after pumping?


How long can you leave breast milk out?

Breast milk can sit out in a bottle or breast milk storage bag for 6-8 hours at room temperature. Anything past 8 hours, you’ll want to discard the breast milk just in case it has started to go bad.



How long can I store breast milk in my freezer bag?

Breast milk stored in a freezer bag filled with frozen freezer packs can be kept in the bag for about 24 hours. At the 24-hour mark, you’ll either want to freeze the breast milk or place it in the refrigerator.



How long can refrigerated breastmilk sit out?

Once breast milk has been refrigerated, and then pulled back out the fridge, you’ll want to make sure that you use the breast milk within 4 hours. Once you have reached that 4-hour mark, it is safest to discard the breast milk.



How to thaw breast milk?

The best and safest way to thaw breastmilk is to remove the breast milk storage bag from the freezer and place it standing upright in the refrigerator. You don’t want to have breast milk sit on the counter at room temperature. If you forgot to set the milk in the fridge, and you need the milk right now, reheating breast milk can be done by thawing the milk in cold water. As the milk begins to thaw, slowly heat the water until the milk is at room temperature. Be cautious that the milk isn’t too hot for your baby.


NEVER microwave breast milk! Microwaving breast milk can cause hot spots in the milk that are dangerous for your baby. Also, microwaving breast milk can kill the antibodies that are there to help strengthen your baby.


Once you have thawed the breast milk, you’ll need to use the milk within 24 hours. At the 24 hour mark, you’ll want to discard the milk.



How to tell if breast milk is bad?

If your breast milk is spoiled, it will have a very sour smell. The same kind of smell you would expect from soured cow’s milk. If the breast milk has gone, it will be very evident.



Why does breast milk separate?

When breastmilk is stored in the refrigerator, it will often separate into two layers. The top layer will often be thick, the then it will look like cloudy water on the bottom. The reason for this is that the top layer is milk fat. That is the “good stuff”, or liquid gold as many will call it.



Why does breast milk change color?

Your breast milk will often change colors. That is nothing to be concerned about, and in fact, it normal. Depending on a mother’s diet, your breast milk will often mimic the color of the foods you eat. For instance, if you eat a lot of greens, your breast milk may have a green hue to it. Breast milk will also often have a green or blue hue to it.





It should be pretty evident that there are a lot of things you need to consider when trying to figure out how to store breast milk in a way that is easiest for you. There is a lot of information here to digest. Come back once you’ve had a chance to think through some things and review your options again. That way you are making a decision you are comfortable with.

I hope I have helped you out and not overwhelmed you with too much information. I wanted to create a one-stop shop for new moms because there is SO MUCH information out there! It was my goal to make finding exactly what you’re looking easier and less time-consuming.



blessings to you, Lisa





how to store breast milk



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