Battling and Resolving Excess Lipase in Breastmilk

While it is unknown how common it is for a mother to have excess lipase in her breast milk, causing it to smell or taste soapy, I come across it often enough that I thought it would be helpful to share how to deal with it, from a mom's perspective.    Christina Williams was gracious enough to write this article, walking us through her journey battling and resolving her issue with excess lipase and her baby who refused to take a bottle, even when she went back to work.  Thank you so much, Christina, for sharing your knowledge and determination!


In preparation to be a first-time mom, I’d been tearing through books and following countless blogs for months prior to my daughter’s arrival. I was sure I had everything in order and was ready for anything motherhood had to throw at me. I could distinguish common rashes from those that are more worrisome, had memorized the slide deck of normal infant poop, and had figured out the optimal wash routine for my growing collection of cloth diapers. Was I prepared to do the seemingly simple task of giving my new baby a bottle after we established our breastfeeding relationship? The thought hadn’t even crossed my mind.

We struggled for months to get my breastfed daughter to take a bottle. We tried every trick in the book – countless fancy bottles, different people, positions and places, and my husband even devised a few feeding contraptions. Nothing worked. She could see that bottle coming at her and would seal those cute little lips right up until it was out of sight. Everyone tried to be encouraging, “She won’t starve herself,” they would say. Maybe not, but she sure liked to scare me into thinking she would try. When I went back to work she reverse cycled, completely refusing milk during the day but eating almost constantly through the night. Staying up most of the night and working all day is not a recipe for success for a working mom. I was lucky to squeeze in two hours of broken sleep a night.

Then, when my daughter was nearly 5 months old, I tasted some breast milk that had been in the fridge for a few days. It tasted rancid, soapy, and a little metallic. No wonder she had been refusing it! I thawed some milk from my freezer stash – that was terrible, too. That confirmed it; there is excess lipase in my breast milk.

What is lipase, and what is it doing in my breast milk? Lipase is an enzyme that breaks down the fats in your milk to help baby digest it. When lipase occurs in excess, this process happens much more rapidly and can make the milk taste off or sour after a period of time. Milk with excess lipase is safe to drink, but some babies dislike the taste and refuse it. Sometimes this change happens in a matter of hours, but many women find that they have 24 hours or more before the milk fats break down enough to alter the taste. 

I think I have excess lipase. What can I do about it? Fortunately, lipase can be inactivated at high temperatures, and milk can be safely stored in the fridge or freezer. Milk must be scalded before freezing, as lipase is still active even at low temperatures. Unfortunately, many women find out that they have excess lipase after establishing a freezer stash and finding that their baby won’t take any of it. If you find yourself in this situation, consider donating. Many babies will accept this milk, and it is often used in tube fed babies who can’t taste it, anyway. My regional milk bank was thrilled to accept my milk, excess lipase and all.

The first step is to determine at what point your milk starts to taste funny. I tasted my room temperature pumped milk hourly until I noticed a difference. I found that I need to scald at work after each pump session, as I don’t have enough time before it turns to make it home at the end of the day and do it all at once. Once you’ve determined your personal timeline it will help you make a plan for scalding your milk.

What do you recommend as the easiest, most effective method to scalding pumped milk? There are two popular ways to scald – in a pan on the stovetop and using a bottle warmer. Both methods require that the milk reach a specific temperature and then cooled.  Some methods suggest heating to 180° and cooling immediately. Others*** recommend heating to 144.5° and keeping it at this temperature for 1 minute, or heating to 163° for 15 seconds and then cooling. Personally, I prefer the bottle warmer method and heating to 180°. I find it difficult to reliably heat to either of the lower temperatures and maintain those temps for the recommended length of time, so I tend to stick to the 180° method. Plus, having a new baby makes even basic tasks seem complicated, so I opt for the simplest option.

***Per Lawrence & Lawrence, bile salt-stimulated lipase can also be destroyed by heating the milk at 144.5 F (62.5 C) for one minute (p. 205), or at 163 F (72 C) for up to 15 seconds (p. 771).

How do you scald milk in a bottle warmer? What supplies are needed? How long does it take? I scald at work 2 or 3 times per day. It takes me exactly 7 minutes to scald and clean up.

Here are the supplies I use (total investment, around $70):

-Bottle Warmer – Select a bottle warmer that doesn’t have an automatic safety shut off. You need to heat the milk to a high temperature, so having the auto shut off kick in mid-scald isn’t going to get the job done. I prefer warmers that contain the entire bottle versus those that allow half of the bottle to stick out the top.

-Stainless Steel Bottle - I don't like to heat in plastic, especially to such a high temperature, and I found that heating in glass is sketchy. My glass bottles broke in the bottle warmer on too many occasions, plus the hot glass can’t be transferred directly into cold ice water or it will shatter. It must be poured it into another container first before cooling. Too many steps if you ask me! Stainless steel allows you do all the steps without transferring containers.

-Digital Thermometer - You'll need one of these regardless of what scalding method you use.

-Container for Ice – Select a container that is deep enough to submerge your bottle and around 3-4 cups of ice. I use a large, glass measuring cup.

-Ice - I like to bring a huge bag of ice in once a week. I can never remember to pack a bag of ice from my own freezer every day, and this seems to make the whole process a little easier.


1. Fill up bottle warmer reservoir, fill the stainless steel bottle with milk, and set the timer for at least 5 minutes. I can usually heat 7-8 ounces in 3-4 minutes. It will take longer to heat if you are using a glass container.

2. Prep your ice bowl with a few cups of ice and cold water. I find it helpful to have this ready before I start heating the milk, as the last few degrees change very quickly and you don't want to over heat. Those last 20 degrees seem to happen in just a few seconds.

3. Start the bottle warmer and stick in your thermometer. As your milk is heating, stir it around a bit with the thermometer so it heats evenly.

4. As soon as you reach 180°, quickly remove from heat and submerge in the ice bath. I let it sit with the lid off for a few minutes while I pack everything else up.


5. After a lot of the steam has escaped and the milk is relatively cool, I put the cap on the bottle and put the container with the bottle inside in the fridge. Usually, I put a paper towel over it if I’m putting in the office fridge. It isn’t necessary to put the ice bath in the fridge, but if I leave it on the counter I will inevitably forget about it until it's too late. The fridge is a nice insurance policy for those Mommy Brain moments.

6. Once completely cooled, transfer the milk into a storage container.

Anything else I need to know? I find that my scalded milk doesn’t always last a full 7 days in the fridge. Your experience may be different, but it’s best to make sure it passes the sniff test after a few days before using. Scalding milk may reduce some of the anti-infective properties and nutritional value of the milk, but not enough for it to be of concern unless baby is getting only scalded milk all the time. Lastly, this all may seem overwhelming, but it is completely do-able, even at work. It took a bit to get in the swing of things, but now it’s just a part of my daily routine.

It took a while to get my daughter to start accepting a bottle, even after I started scalding. After all, we had been conditioning her to think bottles are full of gross milk. It took a few months of patience and persistence, but she now does most of her eating during the day and sleeps at night (well, maybe the sleep part hasn’t been worked out just yet). In true baby fashion, she hates the beautiful, enormous collection of glass bottles I picked out when I was too hormonal to know better. She loves the cheapest, least eco-friendly bottles out there. Typical.

Disclaimer: If you suspect you have an issue with excess lipase, please consult your physician or lactation consultant for advice on how to best manage your situation. I am not a medical professional, just a mom sharing my own experience.


Links to other articles about excess lipase:

Simply Rebekah: Excess Lipase (An Introduction through Becoming a Milk Donor)

Kellymom - My Expressed Milk Doesn't Taste Fresh.  What Can I Do?

La Leche League International - Can Diet Changes Help With Excess Lipase


Have you experienced excess lipase in your breast milk?  

Did it cause difficulties with your baby taking a bottle?