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How to Warm Up Breast Milk: A Complete How-To-Do List

How to Warm Up Breast Milk A Complete How-To-Do List [2023]

As a working mom, factors such as my work, sleep routine, and other obligations posed challenges to breastfeeding. The solution? Like many mothers, you can pump and store breast milk if you wish to continue breastfeeding.

And since breast milk is warm when newborns nurse, many babies prefer it when they drink it from the best baby bottles.

Storing and heating them carefully protected my kids from harmful bacteria and germs. My experience has shown that breast milk may be frozen for months or held for a few days.  

Pumped milk is safe for up to five days in the cooler and up to 6 months in the freezer, though it may lose some of its nutritional and antioxidant qualities. 

Read on how to warm up breast milk and what safety measures to take!

How Can You Properly Warm Up Breast Milk?

How Can You Properly Warm Up Breast Milk

There are several efficient ways to warm breast milk. I made sure to follow these directions carefully to avoid burning my kids.

  • Make use of warm water. Get a bowl of warm water; either reheat breast milk slowly on the stovetop or use the faucet. Breast milk should be poured into the water in a properly sealed container. Let the milk stand for a few minutes until it reaches body temperature. Add warm water if the water starts cooling off too much until the milk is sufficiently warmed. To include the fat that has separated, swirl the milk.
  • Run under the faucet. You can also run breast milk firmly bottled under the faucet. Before bottle feeding breast milk to your child, ensure the tap water is warm (not hot). Although this approach is effective, a lot of water is wasted. So when warming breast milk, the first approach is better.
  • Make a bottle warmer investment. This is most likely the quickest method for warming up a bottle of breast milk, especially for late-night feedings when you don’t have much time. You can get bottle warmers from an online marketplace like Lazada, but follow the instructions carefully to prevent overheating.
  • Make a temperature check. Never give milk to a baby without first testing the milk’s temperature. Shake a few drops onto your wrist to accomplish this. There shouldn’t be any extreme heat or cold in the liquid.
  • Frozen breast milk can be warmed. Before warming frozen breast milk, let it defrost in the fridge. Defrosted milk should be used within 24 to 48 hours. You can also thaw frozen breast milk using the warm water procedure described above, although it will take much longer.
  • Use in two hours or less. You should utilize warmed breast milk within two hours. After thawing, never refreeze breast milk.

QUICK TIP: Breast milk often only lasts up to four hours in a bottle warmer when it is fresh. You should use, keep, or destroy it after four hours.

How to Warm Up Frozen Breast Milk

How to Warm Up Frozen Breast Milk

Breast milk can be easily thawed, but you must follow the right procedures to avoid contaminating the milk. 

When it’s time to thaw breast milk, I always take into account the following advice:

  • Use the oldest milk at your disposal unless there is a valid reason to use more recently expressed milk. Breast milk’s content varies depending on what your baby requires; fresher milk may be more nourishing in some cases.
  • Breast milk should ideally be defrosted by keeping the frozen container in the mini-fridge for a few hours or overnight.
  • Place the milk carton under warm running water to quickly thaw it out. The frozen breast milk container can also be placed in a larger container filled with warm water.
  • Breast milk should not be thawed in a microwave or with hot water. As a result, your baby’s milk can be less nutrient-rich and excessively hot for their mouths.
  • Breast milk naturally separates into a fat layer on the remaining milk. Avoid giving the bottle a vigorous shake; instead, swirl it.
  • Freeze milk in two to four-ounce portions to prevent wastage. By doing this, you can avoid defrosting more than your infant can consume in a few hours and just thaw what you need.
  • Fresh breast milk should be frozen immediately to prevent losing any unless you want to use it within four days.

These are the guidelines I do for defrosting breast milk safely. Remember that if you don’t want to take the chance of overheating the milk, you can feed cold breast milk to your baby.

NOTE: You can buy breast milk from donors. Though donor milk is the best choice for feeding infants, it is crucial to emphasize that it lacks some benefits of breastfeeding with mothers’ milk.

How to Warm Up Refrigerated Breast Milk

How to Warm Up Refrigerated Breast Milk

To warm breast milk from the fridge:

  • Get breast milk from the refrigerator, and reserve it.
  • Use a microwave or a kettle to warm the water. Fill a mug or basin with extremely warm (not boiling) water.
  • Breast milk should be placed in a bowl of warm water in a sealed bag or bottle. For warming, the milk should be kept in a sealed container.
  • Breast milk should be left in a bottle warmer or warm water for 1-2 minutes to attain the proper temperature.
  • Pour breast milk into a bottle using clean hands, or tighten the bottle nipple if it is already in a bottle.
  • If the fat has separated, swirl the breast milk rather than shake it to incorporate it.

Check the temperature of the breast milk before giving it to your child in a bottle. Pouring a little on your wrist will accomplish this. It should be cozy but not sweltering.

Avoid sticking your finger into the milk bottle to avoid contaminating the milk with bacteria. Holding the sealed milk container under hot water from the faucet can also warm it. 

This requires more time and water. Your hand could possibly get burned or scalded.

How to Warm Up Breast Milk on the Go

How to Warm Up Breast Milk on the Go

There are occasions when I need to feed my baby while on the go, without the comforts of home, unless I plan to never leave the house with my little one.

Bring Thawed Bottles

Breast milk thawed can be kept at room temperature for two hours. If your outing is brief, put the bottles in your go-to diaper bag.

Bring a Cooler

Consider a longer-lasting storage option if you anticipate being away for an extended time. Carry the bottles in a milk cooler if your infant drinks chilled breast milk. 

Your breast milk will remain secure for up to twelve hours.

Carry a Travel Heater

Keep the bottles in the cooler, but warm them using a travel bottle warmer if your baby prefers warm breast milk. 

In addition, you can request a glass of hot water from a server at a restaurant or run your container under hot water in a bathroom.

Track how long breast milk has been left out at room temperature and steer clear of keeping breast milk in a hot car to prevent spoilage. 

Always check the bottle’s temperature before delivering it to your child.

It’s typical for your breast milk to change color after warming. It could start to seem blue, yellow, or even brown. Watery breast milk, often blue or clear, is a sign of “foremilk.”

Most of the time, this discoloration does not indicate a problem with your breast milk. Your infant can still safely consume this liquid.

What Should You Avoid Doing When Warming Up Breast Milk?

What Should You Avoid Doing When Warming Up Breast Milk

Want to protect your baby’s health and prevent burning her? Avoid warming your breast milk using these ways.

  • Don’t use the microwave. This device will unevenly disperse heat, raise the risk of burns, and deplete the nutrients in the formula. This technique could be better. Avoid microwaving food or beverages (including formula and breast milk) in plastic since heat may allow the plastic to release BPA and phthalates into food.
  • Avoid using the stovetop. Never put your bottle in a pot of boiling water. This method makes it simple to overheat the formula, and it is unsafe to use plastic bottles because they can melt in high temperatures.

NOTE: Although the sight of blood in your breastmilk may frighten you first, you can continue nursing if this happens; in most cases, the bleeding will stop in a few days. Consult your healthcare professional if it persists or if you have any concerns.

How Should You Store Breast Milk?

How Should You Store Breast Milk

The length of time you plan to utilize breast milk will determine how it should be stored. Here are some useful tips I followed for properly storing breast milk.

  • Wash your hands and all storage containers completely before using the breast pump. If you provide the milk to a childcare provider, mark each container with the date the breast milk was expressed and the child’s name. Find out how your childcare provider wants breast milk labeled and stored.
  • How much breast milk to store? Make small batches. To minimize waste, use 2 to 4 ounces. After your baby has finished feeding, any breast milk still in a bottle must be consumed within two hours or, if rapidly refrigerated, used for the next feeding. An extra container can always be thawed if necessary.
  • Milk should be chilled or refrigerated as soon as it is expressed. The recommended practice is to cool freshly expressed milk as soon as possible. Freshly expressed milk can stay at room temperature (up to 77°F or 25°C) for 4 hours (or 6 to 8 hours if very cleanly expressed).
  • Breast milk can be kept at the back of the refrigerator at a temperature of 4°C or 39°F. Although it can be stored in the refrigerator for up to 8 days, it is better to use chilled breast milk within 4 days.
  • To thaw frozen breast milk, put the container in a basin of lukewarm water or run it under warm water. Never microwave breast milk since it could scald your child.
  • If you won’t use breast milk within 24 hours, freeze it. Don’t fill the breast milk storage container to the top because breast milk swells as it freezes. Once more, place the breast milk on the freezer’s back shelf rather than the door.
    • In a refrigerator with a freezer and a separate door, milk can be frozen for up to 9 months at 0°F or 18°C.
    • If the freezer is a chest or deep freezer (4°F or 20°C), milk can be stored for up to 12 months.
  • To defrost frozen breast milk, store the container or bag in a fridge over the night, lay it beneath lukewarm flowing water, or set it in a jar of warm water. Keep in mind that it is unsafe to microwave breast milk.
  • Once thawed, breast milk can be kept in the refrigerator and must be used within 24 hours.

QUICK TIP: You can learn how to breastfeed without a nursing pillow or cover. However, many new mothers feel that the unique features and extras of nursing pillows are helpful in the initial months.

Which Containers Are Appropriate for Storing Breast Milk?

How Should You Store Breast Milk (2)

Breast milk that has been expressed can be kept in various containers. When I choose a container, it’s crucial to consider the storage location (fridge or freezer) and duration.

To prevent milk wastage, breast milk should be kept in the following sorts of containers in modest quantities (2 to 4 ounces):

  • Glass containers, for me, are the best choice for freezing milk because they keep their constituent parts better than other materials. Glass might break, so it might not be as practical as other materials. Additionally, some daycare facilities might not allow glass containers.
  • Clear, hard-sided plastic containers are frequently a viable substitute for glass ones. Breast milk should always be kept in transparent plastic bottles. Avoid using bottles with the recycle symbol 7 since they may contain BPA.
  • Another option for freezing breast milk is to use freezer bags specifically made for storing breast milk. Investing in bags made expressly for freezing extracted breast milk is crucial. This storage option has the highest likelihood of leakage out of the three. Additionally, if the bag is heated in water and the water level rises above the seal at the top, your milk may get contaminated. Some advice to maintain safety if you choose breast milk freezer bags for storage includes:
    • If you’re using a thinner storage bag, use two of them.
    • Place every breast milk storage bag into a freezer-safe hard plastic container with a cover.
    • Never keep your breast milk in regular plastic storage bags or bottle liners. Use only nursery bags that are specifically made for keeping milk.
    • Water that doesn’t reach the top of the bag should be used to warm the bag. This lessens the chance of water leaking into the bag. There likely was a leak; therefore, you should discard that milk bag if the water you’re using to warm it appears cloudy.

Whichever method you decide on, it’s critical to guarantee a tight seal on the container. Before storing it, ensure the top or seam (if you’re using a freezer bag) is tightly sealed.

How Can You Spot If Your Breast Milk Has Spoiled?

How Can You Spot If Your Breast Milk Has Spoiled

Sometimes it seems like a bottle has been left out too long or the frozen breast milk in the refrigerator isn’t quite right. 

It’s important to remember that breast milk can spoil under these circumstances. There are a few important indicators that breast milk has gone bad.


Much like cow’s milk, the most noticeable signs of deterioration are an unpleasant odor and curdling. 

Your breast milk can separate, but it should combine quickly again. If it doesn’t, it might have deteriorated.

Sour Taste

You should taste your breast milk if you have any concerns. If it’s gone bad, breast milk will taste strongly sour.

Smells Like Soap

Occasionally, breast milk that has been preserved may have a taste or odor that is frequently described as “soapy.” 

This flavor is thought to be caused by an overabundance of lipase in your milk. Although some babies reject the milk due to the change in flavor, this milk is still safe for your baby.

Try fast chilling down newly pumped breast milk after warming it if you think this is what’s happening to your milk. 

Try mixing it with freshly pumped milk if you have previously frozen milk that your baby won’t eat.

There is no known method for removing the soapy taste or smell after the milk has been frozen and thawed. However, some mothers claim adding vanilla essence may make it more tolerable.

If you’re unsure whether your breast milk has gone bad, err on caution and discard it. Note the expiration date of any breast milk you have stored.  

You may write the date and time on many freezer bags and bottles. Initially, use the breast milk that has the earliest date. 

Your freezer should be organized so the older milk is at the front and ready to be removed first.

Frequently Asked Questions

Is It Ok to Overheat Breast Milk?

When breast milk is heated too much, the main danger is that it will burn your baby’s tender mouth and skin when they swallow it or touch the hot bottle.

Furthermore, excessive heat depletes breast milk of many vital elements your baby requires.

If you accidentally heat a bottle of breast milk, you can quickly cool it down so your baby can still drink enough. Make sure the breast milk is consumed within two hours, though.

Why Is It Important to Warm Breast Milk?

Yes, breast milk doesn’t need to be heated. The temperature at which your breast milk must be used after thawing is not critical. 

Your baby can eat it if it has melted into a liquid condition and is free of ice crystals. However, a lot of infants choose warm breast milk. 

Breast milk that has been heated might lose some of its coldness, making feeding time more pleasant. During feedings, warm breast milk can also aid in calming and soothing babies.


Warming breast milk is a relatively frequent procedure. However, safety and quality requirements cannot be assured due to the many variables involved in storage and reheating.

Breast milk can be given to healthy, full-term infants at body temperature or room temperature.

Some healthy full-term and older infants can take chilled milk straight from the refrigerator. This is regarded as the most secure option.

However, breast milk often keeps well in the fridge and freezer, and can be warmed to make it simpler for the infant to consume. 

Use only storage containers or bottles made specifically for breast milk

Nayna Llenos
Nayna Llenos

Hi, I’m Nayna!
I’ve always wanted to be a mother, and I’m lucky and blessed to have two wonderful children to care for and love.
Despite this blessing, there are times wherein I do wonder if I truly am the mother my children need. Am I giving them the right food, care, and discipline to them?
But that is the beauty of parenting — you grow along with your children as they flourish to be their wonderful selves!
I wish to share my experiences with motherhood and how these tips can help you in your parenting journey.
I hope my advices and experiences will prove useful to you and that you have a smooth and wonderful journey as a mother!