How to Freeze Breast Milk

Step-by-Step Instructions for Collecting and Storing Breast Milk In the Freezer

A pacifier and two plastic bottles filled with breast milk
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Breast milk is often referred to as "liquid gold." It can be collected and stored safely in the freezer for many months. Whether you're pumping extra breast milk to relieve breast engorgement or stocking up your freezer to have plenty of breast milk when you return to work, it's easy to save every extra drop that you pump or express by following these simple guidelines.

Level of Difficulty: Easy

Time Required: 25 - 30 minutes

6 Steps

In just six easy steps, you'll have properly frozen breast milk that can be used for up to a year.

Choose Your Storage Container

There are many different types of containers that can be used to store breast milk including breast milk storage bags, plastic bottles, glass containers, and breast milk trays.

When selecting the container that's right for you, think about how long you plan to keep your breast milk in storage. Some breast milk storage bags, for example, are mainly designed for freezing and can be stored flat, and then stacked, which saves a lot of space.

If you use disposable bottle liners for freezing breast milk, they may require additional protection to stop leaking and contamination. If you'd like to freeze your breast milk in harder containers, glass gives the most protection, because it is the least absorbent. Whichever container you choose, it should be clean, BPA-free, and safe for the storage of food.

Gather Your Equipment and Supplies

If you'll be hand-expressing your breast milk, all you need is a clean collection container. If you'll be pumping, gather your pump, pump flanges, tubing, and collection container.

All of your pumping supplies should be clean and dry to prevent any bacteria from entering your breast milk as you pump. Depending on the amount of breast milk that you're able to pump, you may need to have additional collection containers ready.

Wash Your Hands and Breasts

You should wash your hands and your breasts before you begin to pump or express your breast milk. Any germs on your skin can get into your breast milk as you're collecting it. The best way to minimize contamination is by keeping everything as clean as possible. 

Pump or Express Your Breast Milk

Pump for about 10 minutes on each side and collect your breast milk. If you are using the same collection container as your storage container, do not fill it all the way to the top. When your breast milk fills approximately 2/3 to 3/4 of the container, remove it from the pump and replace it with another bottle.

If you are pouring your breast milk from the collection container into a different storage container, complete the collection of your breast milk then pour your milk into the storage containers.

Never fill storage containers to the top. Breast milk needs room to expand when it's frozen.

Seal Your Container

If you're using a storage bag, make sure to close the seal securely and completely. If you're using a plastic or glass bottle, use a solid one-piece screw on cap for the best seal. Bottle nipples should not be used as a cap when you're freezing breast milk.  

Place the Container in the Freezer

Label your breast milk with the date and time of the collection and put it in the freezer as soon as possible. The length of time that you can store your breast milk depends on the type of freezer that you have: 

  • A freezer located inside of a refrigerator can be used to store frozen breast milk for two weeks.
  • Breast milk can remain frozen in a stand-alone deep freezer for one year.
  • Pumped breast milk may be kept in a standard freezer that's part of a side-by-side or top-and-bottom refrigerator-freezer unit with separate doors for up to six months. Set yours to a level that makes your ice cream rock-hard. Most freezers reach this temperature, but if you are concerned at all, you should buy an inexpensive freezer thermometer to set your mind at ease.
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  • Pumping and storing breastmilk. Office on women's health. US Department of Health & Human Services

  • Academy of Breastfeeding Medicine Protocol Committee. ABM Clinical Protocol # 8: Human Milk Storage Information for Home Use for Full-Term Infants. Original protocol March 2004; Revision #1 March 2010. Breastfeeding Medicine. 2010;5(3).

  • Lawrence, Ruth A., MD, Lawrence, Robert M., MD. Breastfeeding: A Guide for the Medical Profession Eighth Edition. Elsevier Health Sciences. 2015.

By Melissa Kotlen
Melissa Kotlen is an International Board-Certified Lactation Consultant and Registered Lactation Consultant.