Breast milk - Milk
Author: TLN

Storing Breast Milk: A Beginner’s Guide

Updated June 2020

All you need to know about safely storing breast milk

Building up a stash of breast milk gives you the ability to schedule date nights, Costco runs and anything else you need to do with the peace of mind that your little one will have access to your breast milk when they need it. While pumping provides you with the ability to build up your supply, there are a few breast milk storage guidelines to follow to make sure your pumped breast milk is safely stored for baby. To help you get started, we’re sharing the basics of successfully storing breast milk, complete with tips and tricks for new moms.

Breast Milk Storage Guidelines

In general, breast milk is relatively simple to work with, but many new moms encounter questions on their pumping journey. For example, how long can you leave freshly expressed breast milk at room temperature? Can you refreeze already frozen breast milk? How long does breast milk last? What’s the limit for keeping that liquid gold fresh in the fridge? According to the Centers for Disease Control and Prevention, here are a few times to keep in mind when you’re storing your freshly expressed and frozen breast milk:

Freshly Expressed Breast Milk

  • At room temperature: up to four hours (or even up to six hours, according to the Mayo Clinic)
  • In the refrigerator: up to four days 
  • In the freezer: between six and 12 months

Previously Frozen Breast Milk

  • At room temperature: up to one to two hours 
  • In the refrigerator: up to 24 hours
  • Do not refreeze previously frozen breast milk 

If your baby doesn’t finish the bottle in one feeding, you have about two more hours to use it before it’s best to throw it out. 

The CDC’s breast milk guidelines define room temperature as 77 degrees Fahrenheit or cooler. For milk left at higher temperatures of 80 to 85 degrees Fahrenheit, we recommend exercising a bit more caution and closely following a three- to four-hour time frame. If your room is in this temperature range or warmer, it may be better to refrigerate your breast milk or place it in an insulated cooler with cold packs.

stored breast milk with dates

What’s Better: Breast Milk Storage Bags or Bottles?

You’ll need to decide how you want to best extend your breast milk’s shelf life: in bags, bottles, or a combo of each. While the best option is whatever works for you, here are a few pros and cons you should know for each storage option. 

Storage Bags

Storage bags are super reliable and almost never break (but remember to seal them all the way so your hard-earned liquid gold doesn’t leak!) and can save you extra space in your freezer or diaper bag because of their thin shape. Storage bags are not reusable, so they tend to add up in price. 

Pro-tip: Freeze your bags lying flat so they can easily stack on top of each other, making milk organization a breeze. You also can buy them almost anywhere—hello, impromptu trip to Target! 


Storing breast milk in bottles tends to be more cost-effective since they’re reusable. They’re also more eco-friendly since you can get multiple uses out of them. However, one downside is that bottles are a bit bulkier and can take up more space in cooler bags. If you plan to pump and use bottles for breast milk storage while on the go, make sure to bring at least four to six bottles with you so you’re fully stocked and can easily combine and transfer from pump to cooler.

Whether you plan to use bottles or bags, having a few extra bags on hand is always great when you need to pump in a pinch. Have a stash at home, in your purse, in the car, at the office—heck, keep a stash at the gym just in case you need them. 

Storing Breast Milk on the Go

As a mom, you have enough on your plate, so worrying about saving your breast milk while out and about shouldn’t be one of them. Enjoy that night out with your friends—just pump and keep some handy extra bags stored in your purse and voilà, you’re good for another four hours! Plus, unless you’re partying hard, who’s really out for that long anyway? #SleepIsGoals

When you get home, it’s always best to immediately store your breast milk in the fridge or freezer. If you plan to use it that night or within the next few days, a refrigerator is fine, otherwise, the freezer is best. 

If you’re pumping in an office and need to stick to a pumping schedule, advocate for a mini-fridge (or at least access to a fridge) where you can store your breast milk during the workday. If you need tips on transporting and storing breast milk, we’ve got you covered.

For any on-the-go occasion, we recommend these products to make storing breast milk super manageable while you’re out living life:

YETI® Cooler

YETI cooler


Why We Love It: This small-but-mighty cooler is just what moms need for a day (or night!) away. It’s compact enough to be ultra-portable, but strong enough to keep your precious cargo cold for hours. Plus, it’s resistant to mildew and punctures.

PackIt® Bags

Packit bottles and coolers


Why We Love It: PackIt® Freezable Breastmilk and Formula Coolers are great because instead of containing ice packs that need to be refrozen, these lightweight and stylish coolers use a built-in freezable gel that keeps up to four 5-ounce bottles cold for hours. Just fold up the bag and freeze it overnight. That means fewer parts for you to keep track of and more space in the freezer at home.

Lansinoh Milk Storage Bags

Lansinoh milk storage bags


Why We Love It: Lansinoh’s breast milk storage bags are known for being super sturdy and reliable, due in large part to their double Click ‘n’ Secure™ seal that helps prevent your breast milk from spilling or spoiling. Plus, you can pump directly into the bags, meaning one less step in your on-the-go pumping session. Just be sure to check that the bags are compatible before you try to pump with them or buy a hundred in bulk.

Kiinde® Twist Cooler Bag

Kiinde Twister cooler bag


Why We Love It: The slim pockets in the cooler keep your storage bags upright, so there’s no need to worry (or cry) over spilled milk. Plus, the design helps secure bags tight against the ice packs for maximum cooling. Every milk bag touches an ice pack, helping to keep every ounce of your breast milk cool while you’re away or traveling with baby!

At The Lactation Network, we’re here to support you at every step of your breastfeeding journey. Looking for the perfect insurance-covered breast pump for your lifestyle or need to reorder some supplies? Check out our shop!