The Problem with Excess Lipase | Exclusively Breastfeeding

Breastfeeding is hard. Anyone who tells you it isn’t is either lying or trying to make you feel bad…& I don’t tolerate either. And even if by some stroke of really good luck, breastfeeding is physically easy, then there is the time factor. Breastfeeding takes a TON of time. Pumping, feeding, storing, transporting, heating. I’ll be the first to say, I sometimes had formula envy…because dumping powder in a bottle (and letting someone else do the feeding) often seemed far easier than the route I chose. Breastfeeding is not for everyone–but my motto is & always has been that some is better than none & we do what is right for us.

I decided I wanted to breastfeed long before I ever had a baby. No need to discuss the benefits here–you all know where to find the facts about how it affects both mama & baby. I nursed my daughter until she weaned herself at 14 months. She never had an ounce of formula before switching over to whole milk when she was 12 months old. For us, it was a wonderful experience, mentally & physically. I loved nursing her. & I LOVE that she has only been to the doctor due to illness once in the last 19 months. Those antibodies really do work! But it was not easy & I learned a lot along the way. I learned a really big lesson the hard way and wanted to make sure I shared–because even if this happens to ONE of you, & you have a knowledge base, this post will be worth it!

After the hurdles at the beginning (please, please have a Lactation Consultant lined up to see within a couple days of giving birth!) we settled into a nice pattern. I was producing about 6-8 extra ounces each day & immediately packaging & freezing them in exactly the perfect way, following these guidelines for storing breastmilk. I had a whole system of labeling & organization. I was stoked. I was stockpiling for the winter. I had “the fear” that one day I would just stop producing & I was preparing for the worst.

Fast forward to December. I came down with a nasty sinus infection. I took one dose of sudafed after 5 days of toughing it out & DOWN went my milk supply. I went to defrost my first bag from the freezer (after 4 months of pumping) and caroline refused it. Hmm. Defrosted another bag. Refused it. I took a whiff & a taste & YUCK. No wonder she was refusing it. It was clearly sour. I defrosted bags from different parts of my stash–all the same metallic/soapy taste. Time to hit google. & google answered. I had excess lipase in my milk. o.m.g. Everything strange happens to me…what now, is this??

[29 hours of pumping…& 450 oz of my milk…down the drain. Only positive: buh-bye baby weight!]


Lipase is an enzyme that is present in human milk that does a lot of beneficial scientific things. An excess of lipase causes the enzyme to break down the milk fat soon after the milk has been expressed.


The major problem with excess lipase is that once the enzyme begins breaking down the milk fat, the milk quickly sours. Typically this occurs within 12-24 hours of expressing the milk.

(**update 3/13–please read the comments section, as I received information from a pediatrician reader who confirmed that excess lipase “changes the taste of the milk to where it doesn’t particularly taste as yummy as fresh BM, but there is NOTHING WRONG WITH MILK AFTER THE EXCESS LIPASE CHANGES THE TASTE.” Wonderful info! Thank you, Dr. Judy!)


If you are one of the rare women who experiences this problem, you will notice that you cannot store milk in the refrigerator for more than 24 hours or it sours. You will also find that any frozen breast milk will be sour when defrosted.


There is no known way of salvaging milk that has soured due to excess lipase.

Newly expressed milk can be scalded at 180° F to inactivate the lipase, but this has nutritional consequences to the quality of the milk & may not always work. This must be done prior to freezing. (& sadly, this did not work for me.)


Despite the challenge of having excess lipase in my milk, I was able to exclusively breastfeed my daughter. I still pumped her evening feeding one day in advance, so each nightly “dreamfeed” was a pumped 5 oz bottle. I nursed her every other feeding of the day.

I froze, thus lost, over 450 oz of breast milk before I knew this was a problem for me. I advise every single new mommy I can, do a test freeze of your milk before becoming a dairy queen & pumping like mad! It would have saved me over an entire day of my life. :(

A few more thoughts on the breastfeeding topic…

  • If you cannot afford the help of a Lactation Consultant, La Leche League provides a 24 hour toll free helpline at 1-877-4-LALECHE.
  • Be sure to check out my BABY LIST for all my essential products for nursing–there is a whole list of stuff that helped keep us going!
  • We successfully used a Medela Nipple Shield when my daughter struggled with latch due to engorgement during the first week. A LC can properly fit you with one.
  • I knew only a couple of people who made it to a year of EBFing so I didn’t have too many mamas to share experiences with. I was most surprised by how FAST it went after we started solids. When my daughter nursed, it was for about 5 minutes total each feeding. She was EFFICIENT! (just like her mama!!)
  • Here in San Antonio you have full access to Methodist’s The Lactation Center services by joining the “Women’s Plus” program for $40–EVEN IF YOU DON’T DELIVER THERE. Big plus–as I delivered at the Military Hospital and never saw a LC. The Lactation Center also has a store with an excellent selection of pumps, nursing pillows & Bravado Nursing bras–my favorite!

[comparing the Medela & Lansinoh Milk Storage Bags]


[10 bags (50 oz) of milk in each stack of bags shown here.]


[& both brands leaked when defrosted. Not sure why. But make sure to defrost carefully & in a container!]


I love hearing breastfeeding success stories! What is your biggest tip for new mamas who are just starting?

Hi! Hello! I am Shawna, the founder of Styleberry Blog. This creative corner of the internet has become a learning haven for moms and creatives, offering a warm and encouraging nudge to those who wish to be better and do better, but often don't know where to start. From Decorating to DIY to Diapers and Paleo-ish Dishes, I strive to make the complicated simple and empower women to take action beyond their personal comfort zone. I subscribe to the Shine Theory & so strongly believe that we shine when the women around us shine and mutual support—lifting up instead of tearing down--will always be the culture here. Are you in? I hope so! Beyond the computer, I run Styleberry Creative where I work with clients to create low fuss, high function spaces that are pretty and practical in San Antonio, Texas and beyond. I LOVE making a house a home. My own studs out renovation is now complete and I am now back to working with clients. Please don't hesitate to drop me a line if you'd like to work together! I hope you’ll join me on this fun new adventure! Xo.