HOW TO FREEZE BREAST MILK
Breast Milk Pouch Preparation, Freezing & Storage.Freezing breast milk properly is essential to preserving its nutritional quality, making feedings easier, and keeping your baby safe. It is important to follow breast milk storage guidelines to ensure the safety and quality of the milk.
Whether you’re building a stash for returning to work, traveling, or just want peace of mind knowing there’s extra milk available, this guide will walk you through how to freeze breast milk correctly—from bag selection to final storage.
Why Proper Freezing Matters
Flat and evenly distributed frozen breast milk pouches are important for even re-warming and freeze drying. You also want your pouches to have homogenized fat distribution—this means those healthy milk fats are evenly spread out in the pouch rather than sticking to the sides. Uneven milk storage can lead to longer warming times, uneven thawing, and a less enjoyable feeding experience for your baby.
Proper freezing also saves space in your freezer, reduces waste, and helps avoid dreaded leaky bags. Remember, breast milk expands when frozen, so it’s important not to overfill storage bags to prevent spills, bag tears, and ensure safe storage.
Before You Begin: Sanitation is Key
Before handling any expressed breast milk, follow these quick hygiene steps:
- Wash your hands thoroughly with soap and warm water.
- Wipe down all work surfaces.
- Sterilize any bottles, pump parts, or bag holders you plan to use.
- Avoid touching the inside of the breast milk storage bag.
Keeping your milk safe from contamination is just as important as freezing it correctly!
Preparing to Freeze Breast Milk
Before freezing breast milk, following proper preparation and handling procedures is essential to ensure the milk remains safe and healthy for consumption. Here are some steps to prepare your breast milk for freezing:
Before Expressing or Handling Breast Milk
- Wash Your Hands: Before expressing or handling breast milk, wash your hands thoroughly with soap and water. This simple step helps prevent any bacteria or contaminants from entering the milk, ensuring it stays safe for your baby.
- Use a Clean Pump and Equipment: Make sure your breast pump and any other equipment you use to express milk are clean and sanitized. Proper cleaning prevents bacterial growth and keeps your milk safe and nutritious.
- Label and Date the Container: Label the container with the date and time you expressed the milk. This helps you keep track of how long the milk has been stored and ensures you use the oldest milk first, following the FIFO (first in, first out) method. You can also utilize higher melatonin content milk for evening feeding.
- Store in a Clean Container: Use pre-sterilized breast milk storage bags to store the expressed milk. If using other storage devices, make sure they are sterilized and air-tight to prevent any contamination and oxidation exposure. Breast milk storage bags are specifically designed for this purpose and are a great option.
- Cool the Milk Prior to Freezing: Cool the expressed milk by refrigerating it before freezing. This step helps slow down bacterial growth and preserves the milk’s nutrients, ensuring your baby gets the best quality milk. Gently swirl the milk to emulsify the fats prior to freezing.
By following these steps, you can ensure that your breast milk is properly prepared for freezing, maintaining its safety and nutritional value.
Step-by-Step: How to Freeze Breast Milk in Storage Bags
1. Chill Milk Immediately After Pumping
Freshly expressed breast milk should be placed in the refrigerator after collection. Let it chill fully in the collection bottle before transferring it to storage bags. Cold milk also transfers more cleanly and reduces the chance of fat clinging to the sides of the bag.
2. Swirl—Don’t Shake
Once your milk has cooled in the fridge, gently swirl the bottle to re-incorporate any separated milk fat that may have collected at the top of the milk. Shaking can damage delicate components like live cells and proteins in your milk. Swirling brings everything back together evenly. Freshly expressed milk retains better nutritional properties, including bacteria-fighting capabilities, antioxidants, vitamins, and fat content, compared to refrigerated or frozen alternatives.
3. Choose a Quality Storage Bag (More on That Below!)
We recommend using bags designed for breast milk storage. Avoid using regular food-grade bags like sandwich bags—they may not be pre-sterile, and allow oxygen to permeate into the milk. They also may not withstand freezing without cracking or leaking.
Factors such as temperature, cleanliness, and proper sealing influence the safe storage duration of human milk and methods to maintain its quality.
4. Transfer With Care
Carefully pour the milk into a sterile breast milk storage bag. Avoid touching the interior of the bag. Use a funnel if you find it tricky to pour from the bottle without spilling.
Remember to maintain hygiene when handling your breast milk to maintain the safety and quality of the milk.
5. Don’t Overfill
Most bags have a fill line—respect it! Overfilling can cause the bag to burst during freezing. In general, aim for 4 to 6 oz per bag.
Tip: Use a kitchen scale to weigh the bags before sealing—it helps ensure consistency in your storage stash. Bottles and bags have a tendency not to be accurate measuring tools. Remember, once thawed, do not refreeze the breast milk to maintain its quality and safety for your baby.
6. Seal it Tight
Press out as much air as possible before sealing. You can place the pouch on the edge of a table to help express the air out of the pouch. Double-check that the zip seal is fully closed. This helps prevent freezer burn and leaking.
7. Freeze Flat First
Lay the bag FLAT in the freezer for its initial freeze. You can use a breast milk pouch flattener tool to get a truly uniform shape. Flat pouches stack neatly and thaw faster.
Let the bags freeze overnight before stacking and organizing.
8. Stack & Store
Once fully frozen, you can stand the bags upright or stack them horizontally. You can use a dedicated bin, plastic storage bin, gallon ziploc bags, or a freezer organizer to keep things tidy and avoid playing “Milk Jenga.”
Best Breast Milk Storage Bags: What to Look For
Not all bags are created equal. Here’s what to look for when choosing the right one:
Product Features
Feature | Why it Matters |
|---|---|
Pre-Sterilized | Reduces risk of contamination. |
Leak-Proof Seal | Prevents messy spills in the freezer. |
Durable Plastic | Holds up well to freezing and thawing. |
Freezer-Safe | Designed to withstand freezing temperatures without cracking. |
Measurement Markings | Helps track ounces and portions accurately. |
Writable Label Space | You’ll need to date and label each pouch. |
BPA-Free Material | Ensures safe storage for baby milk or food without harmful chemicals. |
To store your milk safely in the refrigerator, place it in the back where the temperature is most consistent and avoid storing it in the door due to fluctuating temperatures.
Labeling Tips for Your Breast Milk Bags
Remember to label your bags with the date, time, and amount. This makes it easier to follow FIFO (first in, first out) guidelines when feeding your baby.
Add additional dietary notes if you are keeping track of introducing new food tolerances.
Use a waterproof permanent marker to prevent smudging. Some bags come with writable sections specifically for this purpose.
Pro Tip: If your baby attends daycare, write their name on each bag too.
Freezer Storage Tips
- Designate a freezer section just for milk to avoid cross-contamination with raw meats or strong-smelling foods.
- Avoid storing in a freezer door; milk stored here will experience greater temperature shifts.
- Use bins or baskets to group bags by week or month.
- Rotate regularly — use the oldest milk first.
- Freeze vertically after flattening to save space.
- Use a designated deep freezer for optimal freezing temperatures.
Mistakes to Avoid When Freezing Breast Milk
- Using generic food bags – They’re not sterile, allow oxygen exposure, and can leak or burst.
- Overfilling – Bags can explode in the freezer if filled beyond the line.
- Not labeling – You’ll forget when it was pumped and may waste milk.
- Skipping the flattening step – It leads to chunky, uneven thawing.
- Microwaving frozen milk – Always thaw in the fridge or warm water. Microwaving destroys nutrients and causes hot spots.
Thawing Frozen Breast Milk
Thawing frozen breast milk correctly is just as important as freezing it. Here are the best methods to thaw your milk safely:
- Thaw in the Refrigerator: Place the frozen breast milk in the refrigerator overnight to thaw. This is the safest and most recommended method, as it allows the milk to thaw gradually and evenly.
- Thaw in Cold Water: If you need the milk more quickly, place the frozen breast milk in a bowl of cold water. Change the water every 30 minutes to keep it cold until the milk is fully thawed.
- Thaw in a Warm Water Bath: For an even faster option, place the frozen breast milk in a warm water bath (not hot water) and let it thaw. Stir occasionally to ensure even thawing. This method is quicker but still gentle on the milk’s nutrients.
- Never Thaw in the Microwave: Microwaving can create hot spots and damage the milk’s nutrients. It’s also not recommended to thaw frozen breast milk at room temperature, as this can lead to bacterial growth.
Once thawed, use the breast milk within 24 hours. If you don’t plan to use it within 24 hours, it’s best not to refreeze it, as refreezing can affect its quality and nutritional content.
FAQs: How to Freeze Breast Milk
How long can I store frozen breast milk?
The CDC recommends that breast milk should be used within 12 months and has an optimal freshness taste and aroma of 6 months when stored in a deep freezer.
Can I combine milk from different pump sessions?
Yes, but chill each batch before combining, and it is recommended to combine milk expressed on the same day.
Can I freeze milk directly after pumping?
It’s best to chill milk before transferring it to the storage bag to help the fats stay mixed and reduce expansion during freezing.
Can I reuse breast milk bags?
No—they are single-use only. Reusing can lead to contamination and leaks.
Freeze Breast Milk Confidently
Proper breast milk freezing is more than just tossing a bag in the freezer—it’s about maximizing nutrients, minimizing waste, and making life easier for you and your baby.
Flat milk storage pouches with evenly distributed fat ensure a fantastic future baby bottle or freeze-dried pouch! By choosing the right bags, sealing correctly, and staying organized, you’ll build a milk stash that’s efficient, safe, and mom-approved.
BoobieJuice Freeze-Dried Breast Milk
Once you’ve perfected the process of freezing your breast milk — with flat, evenly distributed pouches and safely stored portions—there’s one more step that can make your milk stash even more powerful and portable: freeze drying it with BoobieJuice.
Our natural freeze drying process takes your very own breast milk and turns it into a nutrient-dense, shelf-stable powder—all without compromising the goodness you worked so hard to pump. By halting lipase breakdown and removing the need for refrigeration, your milk stays just as nourishing, just far more convenient.
Whether you choose our On the Go Single-Serving Pouches or At-Home Big Multi-Serving Pouches, BoobieJuice makes it easier than ever to use every drop of your breast milk—anytime, anywhere.
No thawing.
No cooler bags.
No wasted milk.
Freeze dry your breast milk with BoobieJuice and turn that freezer stash into freedom.
