How to Store Breast Milk Properly & How to Pump


Breast milk is the perfect food for your baby, but you may not be able to feed your baby right from your breast at every feeding. Many moms have to head back to work, while others have a hard time nursing.

Whatever the reason, there’s nothing wrong with pumping and storing breast milk.

But it’s important to make sure that you store your milk properly.

[Read more about Breast Milk]

How Long Can You Leave Breast Milk Out After Pumping?

Manual breast pump full with breast milk is in front of the baby.You’ve just pumped milk for your little one, but you expressed more than you needed. How long can breast milk sit out before it starts to go bad?

Here’s the good news: the milk will probably stay good until your next feeding.

At room temperature, breast milk stays good for about six hours before it starts to spoil. But experts recommend storing the milk properly within four hours if you don’t plan to use it.

How long can breast milk stay at room temperature if the room is warm? Three to four hours is the limit.

If you’re still feeding every two to three hours, it shouldn’t be an issue to store your milk at room temperature until your next feeding. But if the time in between feedings is any longer than a few hours, you’ll want to move your milk to the refrigerator.

Breast Milk Storage Guidelines

Following the proper storage guidelines for your breast milk is essential and will help ensure that your baby gets the most nutrients possible.

There are a few ways to store your breast milk, including:

  • Refrigerator
  • Freezer
  • Ice packs or insulated coolers
  • Deep freezer
  • Travel bag meant for breast milk

You may want to print out a breastmilk storage chart (like this one) and stick it on your refrigerator as a reminder of how long to store your milk and at what temperature.

We’re going to explore all the ways you can safely store your breast milk and the best ways to handle your milk after it’s expressed.

We’ll answer questions like:

  • How long can breast milk stay out?
  • Can you refreeze your breast milk?
  • How long will my milk stay good in the freezer?

How Long Can You Store Breast Milk in the Refrigerator?

Breast milk storage bags for in refrigerator.If you have leftover breast milk after your baby feeds and you don’t plan to use it in the next few hours, placing it in the refrigerator can help extend its shelf life by quite a bit.

How long can you keep breast milk in the fridge?

  • Fresh milk: 3-8 days if stored in the back away from the door
  • Thawed milk: 24 hours if stored in the back away from the door

While you can store it up to eight days, it’s best to use the milk within 72 hours, or three days. After this point, the nutrients in the milk start to degrade.

If your breast milk has been in the refrigerator for a few days, it may separate. Separation is completely normal, and is just the fat rising to the top. Just give the milk a good swirl or shake before feeding to reincorporate the fat.

Can I Add Fresh Breast Milk to Refrigerated Breast Milk?

Can you mix breast milk from different days? You might want to continue pumping to keep up your milk supply, but your baby’s appetite isn’t quite keeping up. Can you add freshly expressed milk to milk you have in the refrigerator?

It’s not a good idea to add warm milk to cool milk, but you can add small amounts of cool milk to refrigerated milk.

Ideally, you want to store milk that’s been expressed on the same day, but you can mix milk from different days.

Just make sure that the original milk doesn’t stay in the fridge for more than four days. The newly-added milk doesn’t do anything to prevent the original milk from spoiling.

Can You Freeze Breast Milk After Refrigerating?

Breast milk frozen in storage bags for baby.Can you toss your breast milk into the freezer after it’s been refrigerated? That depends.

If your breast milk has already been in the freezer for a few days, you may run into issues if you freeze it. Many moms say they notice their milk spoils very quickly if they freeze it after the two- to three-day mark.

Experts say it’s best to just freeze your milk ASAP if you don’t think you’ll use it right away.

If you do need to freeze milk that’s been in the refrigerator, be sure to smell it first. The milk will have an off smell if it’s started to spoil. You may even want to give it just a little taste test. Spoiled breast milk will taste disgusting.

Long story short: Yes, you can freeze refrigerated milk, but it’s better just to freeze right away. And if you’ve thawed out your milk after freezing, it’s not safe to refreeze it.

How Long Is Breast Milk Good for in the Freezer?

How long is frozen breast milk good for? A lot longer than refrigerated milk, but it won’t stay good forever.

  • If stored in the freezer compartment of a refrigerator (old-school fridges): 2 weeks
  • If stored in a self-contained freezer (most common) at <39F: 6  months
  • If stored in a deep freezer at 0F: 12 months

Experts recommend freezing your milk in two- to five-ounce portions. Smaller portions of breast milk will thaw more quickly, and you’ll avoid over-feeding or wasting milk.

Also, you’ll want to leave a little room at the top of your container because the liquid will expand as it freezes.

If you plan to use expressed milk within a few days, it’s better to store it in the refrigerator. Freezing the milk will destroy some of its antibodies, the substances that help fight infection.

Can I Freeze Breast Milk in Plastic Bottles?

Four plastic baby bottles with breast milk on the table.There’s a lot of debate between moms whether it’s better to store milk in breast milk storage bags, or breast milk storage containers.

Both are fine as long as the container you choose is BPA-free and sterilized.

Plastic is the better option. Glass can easily crack, chip or break, especially if you’ll be freezing the milk.

Many moms find that storage bags are the best option for freezing, but they can also rip or tear easily, which can be a problem. If you plan to store your milk in bags, you may want to place your bags in storage containers as an extra precaution.

[Related: 9 Ways Storing Breast Milk]

Regardless of what type of storage container you choose, make sure that you label and date the milk so that you use it before it goes bad.

Can I Store Expressed Milk in Feeding Bottles?

Yes, breast milk can be stored in feeding bottles, but you need to make sure that the bottles are designed for breast milk storage. And you never want to store the milk with the nipple attached.

Feeding bottles designed for storage will come with special caps designed to keep the milk as fresh as possible. If you store the milk in the refrigerator with the nipple attached, you’re introducing potentially harmful bacteria to your vulnerable baby. And you’re letting oxygen into the milk, which makes it spoil faster and destroys it nutrients.

There are so many companies that make storage-friendly feeding bottles, and these are usually the most convenient option because you can go from storage to feeding more quickly than with storage bags.

How to Thaw Breast Milk Properly

Defrosting breastmilk with water normal temperature.When you’re ready to use your frozen milk, it’s important to make sure that you thaw it properly. Improperly thawing your milk can make it spoil or lose more of its nutrients.

How to Defrost Breast Milk Properly

What’s the best way to thaw your milk? The refrigerator.

  • Thaw in the fridge slowly for 12 hours.

Most moms find it easier to put the milk in the fridge the night before you need it, so it’s ready to go when you’re ready to feed.

If you forget to take your milk out of the refrigerator, you can hold the container under running water to thaw it out quickly. Start out using cool water, and gradually increase the temperature until the milk is completely defrosted.

Do not let your breast milk thaw at room temperature.

You can leave your thawed out milk in the refrigerator for up to 24 hours.

Can you refreeze breast milk? No.

It is not safe to refreeze breast milk that has thawed.

How to Warm Breast Milk Properly

Baby bottle electric heater isolated on white.Now that you understand how to thaw breast milk, you may be wondering how to warm it up. After all, thawed milk from the refrigerator is still cold. Babies prefer their meal to be just the right temperature – body temperature.

[Read more about Warm Brest Milk]

There are right and wrong ways to heat up your breast milk. If you do it improperly, you may wind up spoiling the milk or destroying all of its beneficial nutrients.

The safest ways to warm breast milk are:

Running Water

Warm running water is one of the gentlest ways to warm your breast milk.

  • Hold the container under running water. Start with cool water and gradually increase the temperature. Just be careful not to let the water get scolding hot.
  • Place the bottle or bag in a bowl of warm water. Just make sure that no water can leak into the bottle or bag. Place a towel over the bowl to trap the heat.

The goal is to heat the milk to body temperature – no warmer, no colder.

Once your milk is warm, give the milk a swirl to make sure it’s heated evenly.


Steaming is another way to heat your breast milk safely, but it needs to be done properly to avoid overheating the milk.

Here’s how it works:

  • Fill a saucepan with water, and heat until boiling.
  • Place a metal cooling rack on top of the pot.
  • Place the bottle or bag on the cooling rack to warm the milk.
  • Swirl the bottle or bag to ensure the milk is heated evenly.

Do not put the milk directly into the hot water.

Bottle Warmer

Many moms prefer to use a bottle warmer when warming up their breast milk. The nice thing about a warmer is that you can just place your bottle or bag inside, set it and forget it until it’s ready for use.

Some bottle warmers require you to add waters, while others do not. Some are powered by electricity, while others are battery-powered (great for travelling). Most are compatible with bottles of all sizes.

Some models will even sterilize your pacifiers for you.

Can You Reheat Breast Milk?

Most experts will tell you that it’s unsafe to reheat breast milk. Heating, even gently, can destroy precious nutrients. Reheating will destroy even more nutrients and may even spoil the milk.

As a general rule of thumb, you only want to warm enough milk for one feeding session. If you have any leftover after heating the milk once, then it’s best to toss it.

If you can’t stand the thought of throwing out your breast milk, follow your instincts when deciding whether to feed it to your baby. If it looks or smells off, then it probably is, and you should throw it out.

Can You Microwave Breast Milk?

NO! Never under any circumstances should you microwave your breast milk. Microwaving will heat the milk unevenly and create hot spots, which will destroy nutrients and make the milk too hot for your baby to drink.

Bags of milk may also explode in the microwave.

Test Your Milk Before Feeding

Before feeding your baby, test the milk to make sure it’s just the right temperature. Squirt a little milk onto your wrist. The milk should feel warm, but not hot.

How to Hand Express Breast Milk

The mom is breastfeeding her baby with hand expressing.Even if you plan to use a breast pump, it’s important to learn how to hand express your breast milk. You never know when you might need to express your milk by hand. Maybe your pump stops working, or maybe you need to release some milk to relieve pain from engorgement.

Either way, knowing how to express milk by hand is a useful skill that every mother should have. Make sure that you choose a quiet, comfortable and private place to express your milk. It’s important to be relaxed.

The World Health Organization recommends the following technique for hand expressing.

  • Start by washing your hands to avoid contaminating the milk. You’ll need a collection container with a wide mouth. Cups work well for this.
  • Before you start expressing, massage your breasts gently with your fingertips and hands. You can use a soft, warm towel for this, too, if you want.
  • Lean slightly forward to allow gravity to do some of the work.
  • Place your thumb on top of your breast and your fingers below it about 1.5″ from the base of your nipple.
  • Apply pressure toward the chest wall.
  • If you’re having trouble expressing milk, shift your thumb or finger until you feel firmer breast tissue.
  • Continue to apply steady pressure toward the chest wall – not toward the nipple. While doing so, compress the finger and thumb pads together.
  • Switch breasts every few minutes.

The entire process should take between 20 and 30 minutes.

When Does Breast Milk Start to Come in?

When your baby is first born, you’ll produce a type of milk called colostrum. This milk has the most nutrients and antibodies, and is very different from the breast milk you’ll produce later on.

For first-time moms, it can take three to four days for milk to come in. Moms who have gone through at least one pregnancy may have their milk come in sooner. In the meantime, you’ll be producing colostrum.

Don’t worry, you can offer your baby your breast as soon as she’s born. Skin-to-skin contact is important just after birth, and will encourage your little one to latch on. Some babies will feed within the first hour of being born, while others will just want to rest.

How to Pump Breast Milk

If this is your first time pumping breast milk, you might feel a little intimidated or overwhelmed (maybe both). Don’t worry – it looks more initimidating than it truly is.

First, make sure that you’re using a good quality pump that pumps at the same speed your baby would nurse.

Ideally, you want to pump after your baby’s morning nursing session, or you can pump as she’s feeding on one breast.

If you’re at work, it’s best to pump at the same times your baby would nurse to keep your milk supply strong.

To pump:

  • Find a comfortable and quiet spot where you feel relaxed to encourage the let-down reflex.
  • Give your breasts a good massage to encourage the let-down. You can also lean forward and shake your breasts gently to get things started. If that doesn’t work, applying a warm compress might.
  • Follow your pump’s directions, and start by using the lowest suction setting possible.
  • Increase the suction as the milk flow gets stronger.
  • Continue pumping until your milk flow slows down and your breasts feel empty.

Once you’re done pumping, label the bottles with the date, and store either in the refrigerator or freezer.

When to Start Pumping Breast Milk

When you start pumping depends on your situation. If nursing is going well and your baby was delivered on time, then doctors usually recommend waiting two to three weeks to introduce the bottle.

If your baby is premature or there’s an issue that prevents you from nursing at birth, then your lactation consultant may recommend pumping right away.

If you have multiples, talk to your lactation consultant about when to start pumping to boost your milk supply.

How to Transport Frozen Breast Milk

Frozen breast milk in storage bags.Traveling with frozen breast milk? Modern conveniences allow moms to store their breast milk, so they can feed their babies on the go.

But if you’re traveling and bringing along your frozen breast milk, you need to store it properly to keep it from going bad.

For Short Trips

If you’re only traveling for a few hours (less than 12), you can store your frozen milk in an insulated cooler surrounded by ice packs.

Once you reasch your destination, transfer your milk to a refrigerator ASAP. The milk should stay fresh in the refrigerator for 24 hours.

For Longer Trips

If you’ll be traveling for 12 hours or more, dry ice can keep your breast milk fresh. Dry ice doesn’t melt, so it will keep your milk frozen for longer.

When using dry ice, make sure that you wear protective gear, as it can cause frostbite if it touches your skin directly. Store your milk and the ice in a foam cooler so that the vapors can escape.

Remove your frozen breast milk with tongs, and transfer to a refrigerator.

If you’re planning to fly with your frozen breast milk, make sure that you inform security once you arrive at the airport. Only pack as much milk as you need.

Does Breast Milk Stain?

Whether you’re traveling with your milk across the country or just to the next town over, you might wonder whether your milk can stain clothing. If you have to pack your milk, there’s a chance that it might leak – onto your belongings.

And if you get milk on your baby’s clothes or your own clothes (very common), you may want to know what to do.

The good news? Breast milk doesn’t stain. It might leave a mark after it dries, but this mark will come clean in the washing machine.

Now that you understand how to properly store breast milk, you can pump until your heart’s content. Just remember to follow the guidelines for storage and consult with your lactation specialist if you’re unsure of how to handle your breast milk.


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