How To Scald Breast Milk? Way To Make Breast Milk Last Longer

Breastfeeding is the best thing that you can give your baby, but this wonderful practice isn’t always easy. You are lucky if you are one of those who never need to store lots of breast milk in preparation for work. But for most moms, freezing and storing milk is the reality.

You might be one of those mothers who have stored a nice stash of breast milk bags in the freezer, only to find out later that they taste foul once heated.

Soapy, sour, metallic, rancid or just downright gross; your milk can taste like any or all of these.


This is the reason your baby can sometimes reject thawed breast milk. It can be disheartening for a mother that had stored lots of milk, only to find out later that her little one will not take it.

So I'm sharing with you today some proven tips on how to scald breast milk properly.

But before that...

Let me share why breast milk gets sour in the first place.

Lipase In Breast Milk: The Culprit Behind Sour Milk

baby with mom

It is the lipase enzyme in your breast milk that can sometimes give the “off” smell and taste after freezing.

Fats that make the breast milk taste palatable. Lipase basically eats up these fats in your milk, rendering its rancid or metallic tasting during storage.

Is it because of the diet?

Not all moms have this condition; this is also not limited to your diet. You can never predict if you have this condition unless you taste your breast milk after thawing.

The longer your breast milk is stored, the higher the chances that it will taste different due to the lipase activity.

This is not a problem for those who rarely pump, yet for moms that rely on the freezer to extend their milk’s shelf-life, this is a challenge.

How To Scald Breast Milk

Scalding milk prior to freezer storage prevents the formation of metallic aftertaste and sour smell.

So what exactly is scalding?

Scalding means bring the breast milk to near boil. It’s not fully boiling per se, you are simply heating it enough to make it last longer during storage.

Frozen milk’s nutritional value diminishes through intense heating and prolonged frozen storage, but it is still far superior in quality than all the formula milk brands in the market.

I have done my own experiment with breast milk storage when my babies were still a few months old.

But let me warn you:

Scalding milk takes patience; it is time-consuming especially for a working mother like me. But if you are to ask me, all that time spent doing this extra step daily is worth it. I was able to breastfeed exclusively for ten months, despite juggling my time as a working mom.

To scald breast milk, you will need the following items:

  • Digital thermometer – You will need this so as to be sure that you will not overheat your milk. It will be better if it has an alarm function to trigger you.
  • Stainless steel bottle – When boiled, plastic bottles can leach or melt. Some brittle glass bottles can also break if boiled and immediately cooled. Your best bet is to use a stainless steel container or bottle that can withstand the temperature changes in between warming.
  • Bottle warmer – You will need a bottle warmer if you want to easily control your heating temperature. If you don’t have this on hand, you can also use a stainless steel saucepan for heating.

​Ideally, your breast milk starts to turn sour at around 24 hours or less in the fridge. Before this happens, you have to scald your milk to prepare it for freezer storage. As for myself, I usually scald a whole day’s worth of pumped milk at night before dinner. The process is very simple once you get the hang of it:

1. Put around 4 ounces of pumped milk in the stainless steel bottle. If you're using a saucepan, add in about ¼ cup of sterilized water to the saucepan to heat the milk faster.

2. Prop the bottle into the bottle warmer or into the heated saucepan with water.

Prop in the digital thermometer. Take note to monitor the milk temperature throughout the process. Stir the milk while being heated to prevent the formation of an oily film on top.

Heat the milk to around 150 °F to less than 180 °F for about 15 seconds. Do not bring the temperature higher or you’ll deactivate more nutrients and protein as the milk reaches boiling state.

3. After heating the milk, immediately put the bottle in ice water to cool it fast. If you are using a glass bottle, handle it with care as it can crack in cold water. Submerge the bottle in an ice bath until the milk has cooled down to body temperature.

4. Once the milk has cooled, pack it in small bags, seal, label with date and put it them in the freezer. You can also store the scalded milk in the fridge for around 5 days without worrying whether it will taste sour. Scalding will keep it fresher and longer as compared to freshly expressed breast milk.

5. Wash all the containers and bottles. Ready them for another day’s scalding.

6. To reheat your frozen milk, thaw it in the fridge for around 12-24 hours. You can also put it in running cold and then warm water for a few minutes. If your baby wants his milk warm, immerse it in warm water for a few minutes.

Take note:

Do not use the microwave to scald or even reheat your breast milk. It is unsafe as it can cause uneven heating of the milk; some parts can already be hot enough to burn baby’s mouth while another part will still be cold.

​Tips And Tricks For Successful Scalding And Breast Milk Storage

# Say no to microwave heating

Never ever use the microwave to scald or even reheat your breast milk. The problem does not lie in the microwave itself but from the heat created by it. Warming any liquid through microwave is unsafe as it can cause uneven heating; some parts can already be hot enough to burn baby’s mouth while another part will still be cold. Heating through microwave will also spoil faster your breast milk due in part to the unequal heat distribution created.

# Try and taste your milk

You might be thinking that too much lipase in breast milk is rare. To be sure this isn’t your problem, try to freeze and thaw your breast milk. Take a taste and be your own judge.

Frozen and reheated milk will always taste different than freshly refrigerated milk. Freezing will always make the milk taste like something is “off”. Sometimes, the difference is less obvious but if your frozen milk tastes metallic, then you really need to scald your breast milk.

# Clean and sterilize everything before storage

To minimize the gross breast milk taste, clean and sterilize every container, pump accessory and breastfeeding bottles. You can freeze right away the pumped breast milk but to minimize any sour or metallic odors and aftertaste, but sterilize everything first.

Double bag your milk for sanitation purposes. Double-bagging will also protect your milk from acquiring the smell of other food (such as frozen meat or seafood) that is stored in your freezer.

# Observe proper positioning and storage at the fridge

Your milk bags must be positioned at the center of the freezer. Too close to the sides and you’ll run the risk of uneven freezing and temperature changes. This is especially true for self-defrosting freezers.

Store your breast milk in small portions to minimize wasting and overfeeding. A maximum amount of 4 oz. per container bag will do. Flat the bags to freeze. Take note to rotate and label your stash. The oldest must be on top. Practice first in, first out to make sure that you use up first the oldest batch.

If you can regulate the freezing temperature to stay the same all throughout, it is possible to store breast milk in the freezer for about six months. For leftovers, don’t thaw and refreeze milk, it will grow stale quickly. Once thawed, just put it in the fridge and consume within 24 hours.

# Watch out for signs of infection

If mom’s expressed milk appears to be pinkish or with streaks of blood, you can still scald it and store as usual. If you have a fever or if the milk appears to have pus, do not discard the milk outright but seek your doctor’s advice immediately.

# Make the most use out of your breast milk

If you have some sour-smelling milk, don’t throw it right away. You can use it for baby’s bath. Breast milk can help moisturize and soothe baby’s irritated skin due to eczema, chemical irritation, diaper rash, or sunburn.


bottle feeding baby

Scalded milk is still better than formula milk. It may lose some nutrients during the heating process but this is your best bet to ensure that your frozen milk stays fresh longer. Just take note not to feed baby scalded milk all the time.

For your baby, nothing beats the experience of latching on to mom. Breastfeed your baby whenever there is an opportunity. Eat well and stay hydrated so that you can pump adequately throughout the day.

Scalding involves a lot of effort. Raising a child properly rarely come easy, and all that pumping, scalding and freezing of milk takes a lot of resources and energy. Motherhood is always a challenge, but having a healthy child is worth all that and more.


Sarah Morgan

Chief editor of WellBeingKid.com and striving mom-extraordinaire.Let me share and inspire you with my daily struggles to live a healthier and more fulfilling life.

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