On Scalding

Imagine this: you pump an ounce or so per day while you’re on maternity leave, building up your freezer stash for when you return to work. The day approaches, so you thaw some out to practice giving your baby a bottle. As you gently warm it, hoping your babe will accept the nipple, you catch…an odor.

Your milk smells weird, so you taste it. Soapy. Your baby turns his nose and won’t drink it.

What’s going on here? Well, human breastmilk is a living fluid. We have live cells in our milk that kill bacteria, break down fats. The substance is always soap bubbleschanging.

Sometimes, a woman’s milk will have high levels of lipase, which is the enzyme that breaks down fat. When human milk is frozen, the cold temperatures slow but do not stop the lipase from digesting the fat in the milk, and so it changes in taste and odor.

The milk is still safe for baby to drink, so if your kiddo will tolerate, feed away!

But what should moms do if baby won’t drink the milk?

Unfortunately, the already-frozen milk is already soapy. One option moms have would be to wait until baby is eating solids and mix this milk in with baby’s food to mask the taste.

Going forward, mom or dad can scald the expressed milk to deactivate the lipase enzymes. To do this, heat the milk until it is bubbling but not boiling, then cool the milk quickly. 


A skin might develop on top of the hot milk. This is ok–just scoop it off with a spoon and discard so it doesn’t gunk up your bottle nipple.

Working moms often find they can do this at their desk by using a bottle warmer after they’ve pumped their milk and putting the scalded milk directly into their cooler.

But what if the milk smells sour or rancid?

This milk, too, is most likely safe for baby. The change in taste in this case is likely because of the composition of the milk. Possible culprits could be your drinking water, fish-oil, flaxseed supplements, or any foods like anchovies that contain rancid fats.

Try avoiding all of these and experiment with a small test batch of frozen milk to see if that helps.

In the case of sour or rancid milk, scalding will unfortunately not help…it could make it worse. If avoiding all of the above still results in sour milk when thawed, you could talk to your doctor about taking beta carotene or vitamin E supplements.

If you know a mother planning to build a freezer stash, suggest the following tip:

Freeze a small test batch first, and thaw the milk after about a week to taste/smell if it has changed and her baby will take it. 

This will help avoid discarding or finding new use for large amounts of frozen milk.

Did your milk change flavor after freezing and thawing? Leave us a comment to share your solutions!

**Our blogger is an accredited breastfeeding counselor with Breastfeeding USA.

Image by Lee Haywood via Flickr.

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