Do you have extra breast milk that you need to freeze? Here are the basics of how to store your breast milk in the freezer, how to pick the best breast milk storage bag for you, and how to figure out how many milk storage bags you’ll need.
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Breast milk storage bag basics
Before you buy breast milk bags (and especially before reading any reviews), a few general things that you should know:
- Most storage bags cannot be reused – bags made out of plastic are sterilized for single use. However, there are now also special reusable breast milk storage bags made out of silicone.
- All plastic breast milk bags leak sometimes, so if you go to amazon, you’re going to see “my breast milk leaked when I used these bags” in the reviews for every single option. Your goal is to get a bag that leaks less often than most other bags, and then to defrost your milk in a way that minimizes or eliminates waste.
- The milk measurements on breast milk bags (for pretty much all brands) are not particularly trustworthy. If accurate amounts are important to you, measure the amount of milk in a bottle or on a food scale before you put it in the storage bag.
- Keep a Sharpie with your breast milk freezer bags and write down the amount and date pumped on the bag. If your milk may be used in a childcare setting at some point in the future, write your baby’s name on it as well.
- When you’re freezing breast milk, lay it flat to freeze and then put the resulting frozen brick into a gallon-sized zip-top plastic bag for long-term storage. Storing breastmilk flat saves space versus freezing upright. Additionally, the plastic bag will help prevent the breast milk from getting freezer burn.
- Once you fill up a zip-top plastic bag, write the month that milk was pumped on a sheet of paper in big block letters with your Sharpie and then put that in the bag. This way, you don’t have to dig through your freezer to find the oldest milk, which you should use first.
How much milk should you freeze in each bag?
There’s no definite answer for this – everyone manages their milk differently.
If you have no idea how much you should freeze in one bag, I’d start with freezing about what your baby takes in one feeding.
If you end up needing less than you have frozen in one bag, you can thaw the milk in cold water or in the refrigerator and put it in separate bottles for multiple feedings. Just make sure you use the milk within 24 hours of thawing.
Pumping into breast milk bags versus just using them for storage
There are two ways to use breast milk freezer bags:
- Pump directly into the storage bag (usually by attaching the bag to the pump using an adapter).
- Pump into a bottle and pour the milk you want to freeze into the bag. (Note: If you do this, use your flange as a funnel to avoid spilling milk.)
Which one you’ll want to do depends on your system for handling and storing breast milk. If you pump just enough milk for your baby (with maybe a little extra to freeze), and you are usually with your baby, it probably doesn’t make sense for you to pump directly into storage bags.
On the other hand, if you are an oversupplier who frequently freezes the milk from one pumping session per day, pumping directly into the breast milk storage bag saves you the hassle of washing two bottles.
Also, some people who work or are apart from their baby during travel prefer to transport milk in breast milk bags instead of bottles, because they take up less room. If you’d rather carry breast milk back and forth in storage bags, then pumping into them directly might be easier.
Six best breast milk storage bags
Below are six of the best breast milk storage bags:
✅ Strong bags with a double seal
✅ Durable, silicone bags that don't leak
✅ Easy to freeze flat
✅ Pump into, store, and feed from the same container
✅ Extra thick sides for durability
Medela Pump and Save
✅ Can pump directly into bags using included adaptors
Here is more information on the pros and cons of each type.
1. Lansinoh Breast Milk Storage Bags
Lansinoh makes a great, lower-priced breast milk bag that is compatible with several breast pumps.
- Strong bags with a double seal
- Ability to pump directly into the bags using an adaptor with Lansinoh pumps as well as with some Ameda, Evenflo, and Medela pumps
- Easy to store breast milk flat with these bags
- Holds more milk than other bags (technically 6oz, but I’ve put up to 8oz in there without any issues)
- Low price
- Adapters not compatible with Spectra S1 or S2 (only the Spectra manual pump)
Here’s a Lansinoh bag in action in a story:
2. Junobie Reusable Breast Milk Storage Bags
Junobie bags are made of silicone, are very strong and are reusable!
- High quality, silicone bags that don’t leak.
- Reusable and eco-friendly
- Can be used after you finish breastfeeding (similar to Stasher bags)
- Doesn’t make sense for building a large freezer stash (more useful if you frequently freeze and use milk)
- The bags are on the expensive side
You can get 15% off Junobie reusable breast milk storage bags when you use this link.
Below are some stories that I did on Junobie bags:
3. NUK seal N’ Go Breast Milk Bags
NUK breast milk storage bags are another basic, low-priced option.
- Durable bags with a double seal
- Easy to pour out of
- Lays flat well in the freezer
- Low price
- Not designed to work with any adaptors
4. Kiinde Breast Milk Storage Twist Pouch
The Kiinde Breast Milk Storage Pouch isn’t just a breast milk bag, it’s a whole feeding system!
- With this breast milk bag, you can pump into it and then store, warm and feed right from the bag (you will need to buy an adaptor separately that fits your pump; all major breast pump models are supported)
- No need to ever transfer milk, which means fewer spills
- No washing bottles, ever
- Higher price point, and exclusive pumpers will need a lot of bags
- Higher level of waste than pumping into reusable bottles (however, these bags are recyclable)
- To use the full system, your baby will have to take the Kiinde Squeeze bottle for feeding (some babies are picky about what bottles they will take)
You can see how it works in the below stories:
If you want to check it out, you can get a free Kiinde starter pack here. You just pay $6 for shipping! If you like it, you can get the whole system for 50% off.
5. Dr Brown’s Breast Milk Storage Bags
These storage bags are built to be extra sturdy.
- Has extra thick sides for durability
- Double seam to prevent leaks
- Doesn’t lay as flat as other breast milk bags (and it’s difficult to get the air out), which makes storage harder
- Not designed to work with any adapters
6. Medela Pump & Save
The Medela Pump & Save bags come with adapters that can be used with most Medela breast pumps.
- Can pump directly into these bags using adaptors, which are included
- Good for pumping when you’re away from your baby
- Easy to spill when pouring into bottles if you don’t remember to turn the bag sideways (otherwise the milk pours out of the adapter holes)
- Smaller than other breast milk storage bags (only holds up to 5oz)
- Can be difficult to seal if you get any breast milk in the sealing area
What to consider when choosing a breast milk storage bag
So which of these six breast milk storage bags should you get? Here are some things to think about.
Do you want to pump directly into breast milk storage bags?
If so, you’ll want a breast milk bag that is intended to work with an adapter and works with your pump.
(For breast milk storage bags compatible with Medela, your options are Pump and Save, Lansinoh, and Kiinde. If you’re wondering how to pump into storage bags with a Spectra, Kiinde is your best bet.)
If you do not want to pump into storage bags, I would cross the Pump and Save and Kiinde breast milk bags off of your list.
Do you want to use reusable breast milk storage bags, or disposable bags?
If you’re planning to freeze a lot of extra milk and build a large freezer stash (possibly so that you can wean early), it makes sense to use disposable bags.
However, if you prefer to store milk in bags because it takes up less room, or if you have a system of freezing and using milk (maybe you freeze milk you pump at work on Fridays to feed on Mondays), then the Junobie reusable bags can make a lot of sense.
How many breast milk storage bags do you need?
It depends on whether you’re pumping into bags or not, and how much extra you’ll have to store. If you’re pumping into bags, you’ll need twice as many as the number of pumping sessions you’ll be doing that.
For example, if you pump directly into storage bags once a day due to oversupply, you’d need two bags per day, or about 60 per month.
On the other hand, if you’re storing extra milk that you pump into bottles, you can calculate it by determining the number of ounces you want to store in each bag and the amount each day that you usually have leftover.
Say you have 5 oz extra each day and want to store in 3 oz portions. You’d have an extra 35 oz each week, which divided by 3 is 12 bags. Twelve bags per week means you’d need about 50 per month.
If you will need a lot of breast milk storage bags, price might be a big factor in your choice. While prices fluctuate, the Lansinoh, Dr. Brown’s and NUK bags tend to be the cheapest.
How much storage space do you need in your bags?
If you generally freeze milk in small portions, this isn’t something you need to worry about, but if you like to freeze 6oz or more in a bag, the Lansinoh is the best option.
What do you think is the best breast milk storage bag? Tell us in the comments!