Excess Lipase: An Introduction

Update October 2014: I have taken my experiences with excess lipase activity, combined it with interviews with trusted medical professionals, and turned it into a 40+ eBook. If you are looking for more information about excess lipase activity and support from a mother who has been there, then this eBook is for you.

Click here to learn more about my eBook “Why Does My Breast Milk Taste Bad?”


Excess Lipase: An Introduction

I have excess lipase in my breast milk. Coming to that conclusion has been an extremely emotional journey for me. It has been filled with many questions and even more tears.

What is lipase? Lipase is an enzyme that is found in every woman’s breast milk. It is there to help break down the fats in the milk and aid with digestion. There are a few rare women out there who have an excess of lipase in their milk. The extra lipase causes the break down in the fats to happen very quickly and it results in bad smelling and bad tasting milk.

*** UPDATE 2/16/13: I have just learned (from my very well educated lactation consultant & the book Breastfeeding Guide for the  Medical Profession by Ruth Lawrence) that the problem isn’t that women have extra high levels of lipase, but that they have high lipase activity.  What does that mean?  There isn’t extra lipase in your milk, but the lipase activity (breaking down the fats in the milk) is high.  This small clarification in terminology doesn’t change how to test & treat your milk through scalding.  It simply reinforces that there isn’t anything wrong with the composition of your milk.  There isn’t anything wrong with the levels of lipase in your milk; it just breaks down those fats extra fast.

How did I discover I had excess lipase? Nate was home alone with Grace one evening while I was out enjoying a Girls night with church friends. While I was gone Grace refused to drink from her bottle and was very fussy all evening. Just before I got home Grace calmed down enough to drink 2 ounces from the bottle and fell asleep.

Nate and I were both pretty frustrated that the night hadn’t gone well. While we were talking it over, I reached over and picked up the bottle of milk that Nate had been giving Grace. I smelled the milk and then tasted it. It tasted AWFUL! Something was definitely not right. I started freaking out. I have been storing milk in my freezer for months and now there was something wrong with it????

That night I started doing some online research to see what could be causing my frozen milk to “go bad.” That’s when I found out about having excess lipase.

How can I be sure that is the problem? In the online research I did, I came across several women who wrote about scalding their milk to halt the lipase from breaking down the fats. To test my milk I pumped a fresh batch and then scalded half of it. Then I took small portions of each and put them in the fridge and the freezer. Overtime I did a sniff/taste test to see how long the fresh and scalded milk stayed good.

My regular fresh milk still smelled fine in the fridge after 12 hours, but by 24 hours it was starting to turn “bad.” The scalded milk is still good and sweet tasting after a week! My freezer test isn’t done yet. After a week, both samples taste fine. I plan on checking on them both in another week.  UPDATE:  Several months later and my scalded freezer milk is still fresh!

The fact that my scalded milk outlasted my regular fresh milk in the fridge confirms that I have a problem with excess lipase. Normal breast milk should last in the fridge for about 8 to 10 days. Mine only lasted one day. That’s not good. Not good at all, but the scalded milk is still fine!

Can Grace still drink my milk? Yes. There is nothing nutritionally wrong with my breast milk. Any of it that is older than 24 hours just tastes bad. Some babies don’t mind the taste and will drink it just fine. However, Grace doesn’t like it and won’t drink it. Honestly, I don’t blame her at all! It really is nasty.

What can I do about it? Scalding my freshly pumped milk before I freeze it seems to be my only option.

In the future I’ll post the details of how I scald my milk and why this has been such an emotional struggle.

Want more information on excess lipase activity? Click here to check out the book!



  1. cherith says

    hey there, my mother in law has the same thing. I will message her and ask her what she does about it. When I babysat for her, she had me mix the frozen with the fresh…..I’ll try to get more details for you. Good Luck!

  2. Mandy says

    What causes excess lipase? I had gestational diabetes and now learning that I have excess lipase (knowing that’s a pancreas issue), I’m concerned this is something to further investigate.

    • says

      Mandy, I’m not sure that there is a known cause for it. However, I don’t believe it is any cause for alarm concerning your health. The only side affect is that the milk gets a bad taste, but even bad tasting milk is perfectly healthy for babies to drink.

  3. Jessica says

    Hi, Rebekah. Great post! I’m pretty sure I have this issue. I was wondering if your baby was gassy and had frequent runny diapers. My baby has excessive gas and I’m curious if there is a link to this. Thanks!

    • says

      Jessica, although I am not a medical professional, my guess is that the excessive gas isn’t related to the lipase issue. There really isn’t anything wrong with excess lipase milk except for the taste, so it shouldn’t cause digestive issues. Also, I haven’t heard other women complaining about that being a side effect from the bad tasting milk. Perhaps your little one has a sensitivity to what you are eating. Dairy is pretty common.

      Feel free to contact me if you have any other questions about this excess lipase journey!

  4. Beth says

    I’ve been having a sour smell with my frozen milk, not soapy or metallic. I was worried about lipase when she was first born but she took frozen milk happily in October and November. So I didn’t worry. But now as we’re getting ready for me to go back to work in under a week I’m noticing that she doesn’t like the frozen milk (which smells stronger and tastes stronger than fresh) but will drink milk that’s in the fridge for 1 – 3 days. I’m currently testing my milk and am worried that I’m going to have to toss my stash. The milk from the freezer became un-drinkable after 3 hours post-defrosting but my daughter took 1 oz of it and more from me.

    Could the sour taste be lipase?

  5. Jem says

    Just wanted to say thanks for the info :).
    I just had this problem tonight for the second time and originally thought I had not rinsed the bottle out properly so I have been extremely diligent with my rinsing and low n behold it happened again tonight!
    Nice to know im not the only one :)

  6. says

    hi, thank you for the sharing. I have that problem to. And will try to scald my EBM later. Hope that issues will settle with my case. Tq again

  7. Natasha Cox says

    Just wondering if another way to tell about excess lipase in your milk is the quick separation of the whey and the cream (within an hour)… the reason I ask is that my 9wk old will occasionally take an EBM bottle but only when it’s the weakest in fat content..

    • says

      Honestly, I don’t know. I’ve never read/heard anything about milk separation time being related to lipase issues. It is an interesting theory though.

  8. Missy says

    I think I have this problem and wonder if all the milk you had frozen before you realized it needed to be scalded was a lost cause and needed to thrown away. I REALLY don’t want to thow away 4 months of stored breast milk! Please tell me there is a way to fix this problem without throwing all the frozen milk away.

    • says

      Missy, start by using your newest frozen milk and then work backwards. Some women can freeze their milk for a couple weeks before it turns, so your freshest stuff would have the best chance of being ok.

  9. Danielle says

    My daughter isn’t refusing the bottle but last week i went to dump some milk that was sitting out for awhile and it smelled like eggs. It doesn’t taste bad to me and I’ve been giving some to my toddler as well and he takes it just fine. I was wondering if the egg smell could be related? I originally had a hind milk issue so ive been storing my milk in a large container and then dividing it up into bottles then freezing the remaining amount. The smell is pretty overwhelming but from what I can tell it doesn’t taste like eggs or sour.

  10. Goska says

    Wow…interesting how many women experience this. My daughter just turned 9 months and up until now I never had the need to give her frozen milk. I had a lot of excess milk for the first 5 months, probably due to also pumping frequently to keep up the supply. I did not mind spending the extra time pumping as I was always of the thought that I’d rather have too much than not enough. However, on few occasions recently I had to dip into my stash, only to taste how awful the milk was! My milk is not metallic or sour tasting…but rather almost has a ‘pukey’ taste to it. Gross! I have sooooo much milk frozen and am devastated at the thought that I may have to dump it out…however, so far the little one doesn’t seem to mind it at all. She drank 6oz straight just a little while ago and was perfectly content…bless her heart cause I would not touch it! Also, my milk did n it change in taste or smell when refrigerated…I would have it in there sometimes up to 5 days before giving it to her and it always tasted pretty good..definitely not as good as the fresh stuff but nothing close to how the defrosted milk tastes.

    These days I only pump once in the evening and I give her that pumped milk the next day, some mixed with her cereal and the rest for a bedtime bottle. Since she started eating solids and has gotten very fidgety and distracted with age, nursing has become very challenging and my milk supply has diminished greatly!!! I just pray that I have enough for at least the first year of her life and if need be that she will continue to drink the pukey tasting frozen milk. Good luck to all the breastfeeding moms out there!!! Only we know how much dedication it takes to provide our munchkins with the perfect nutrition…it is definitely worth all the sacrifice!

  11. Robin says

    I just tapped into my freezer stash for the first time today. And, yup, I got it… Bad tasting, soapy, nasty milk. I’m crushed. I am going to try what you suggested about testing my more recently frozen milk. Hopefully it isn’t all bad. My daughter would not take the bottle, though she was pretty tired & fussy, so I may try again later.
    Did you find that you had this problem of excess lipase with both of your children? I seem to recall with my older son I had frequently ‘spoiled’ smelling/tasting milk. But with him, we had a lot of other issues with breastfeeding and only lasted 4 months before we decided to end the battle and switch to formula. (Supply, lazy feeder, slow weight gain) With
    my daughter nursing has been wonderful & I want to keep at it for at least a year. I guess I am just curious to know if it is an issue for you once, it always will be.
    Thank you for sharing your story. It has given me much hope. I plan to go the route of scalding before freezing any more of my milk. And I pray that not all my precious stash is a waste.

    • says

      Robin, since writing these posts about my experience with my daughter I have given birth to a little boy. Sadly, I have excess lipase issues with him also. It sounds like you probably had a lipase problem with your first born, but didn’t realize it at the time. This whole thing is just so frustrating, isn’t it?

      I sure hope you can still use some of your freezer stash! Start with your newest stuff and work backwards.

  12. Jen says

    I’m beginning to think this may be the issue I’m having. My refrigerated milk tastes soapy. I’m starting my research… And so sad if all that freezer milk has gone to waste. I return to work in one month… She will be 6 months and won’t take a bottle. This may be why

  13. says

    I have the same problem and was so bummed when I found out. I pump anywhere from 10-20 oz every 4 hrs after my daughter has nursed and have 2 freezers full of milk. My daughter is 9 weeks and will take some bad tasting milk but sometimes won’t take it at all. I was told to just give the fresh stuff when I pump in the morning before work and breast feed when I’m with her and donate all my excess milk. They take excess lipase milk because they pasteurize it all. I wish I knew what caused excess lipase.

    • says

      I wish I knew what caused it too! I never wanted to experiment with different things because I didn’t want to take the risk of “losing” more milk to the bad taste. It sounds like milk donation would be a really good fit for you. You might want to look into scalding some of your milk just to have a small back up stash that you can keep for your daughter.

  14. Dani says

    Hi Rebekah,
    I recently discovered that I may have the lipase issue. I am so sad, because my son is 6 months old and I have a HUGE stash of breast milk in my downstairs freezer. This whole time we though he wasn’t taking the bottle because he preferred the breast, but now I totally think its because my defrosted milk tastes like vomit! I am still in the experimenting phase, but so far my fresh milk tastes ok after being in the fridge for the past 12 hours. What confuses me is that we froze fresh milk immediately the other day, then thawed it a few hrs later, and it tasted horrible!!! Have you ever heard of this? Do you have to scorch your milk immediately, or is it ok in the freezer unscorched for awhile? This is so frustrating! I dont know what I am going to do:(

    • Rebekah says

      Dani, I’m not quite sure what to tell you about your frozen milk. Freezing your milk should slow down the lipase activity, not trigger it to go faster. However, all milk does change flavor some when it has been frozen.

      Concerning your large frozen stash, I would work backwards (newest to oldest) to see if you can still use any of your newer milk. Anything that you can’t use, please consider milk donation.

      Let me know if you have any other questions.

  15. Dani says

    I guess I meant to ask, why is it ok in the fridge right now after 12 hrs, but not in the freezer especially since it was frozen immediately? It just doesnt make sense, unless freezing it has activated the lipase in some way??

  16. Lisa Davido says

    I found out I had a lipase issue and had to dump over 300 ounces of frozen breastmilk after my first son. I’m now pregnant again (3 1/2 years later) and am wondering if I will have the same lipase issue again. Do you know anything about this? Thanks in advance!

    • Rebekah says

      Lisa, there hasn’t been enough research done to know for sure, but it seems most likely that it will happen again. I am on baby number two and I have lipase issues again. Definitely test your milk several times that first month before you freeze a bunch without scalding it.

      Best of luck with the end of your pregnancy and your birth!

  17. Selda says

    If you are not able to donate your freezer stash, there are other ways of using it instead of throwing it away, like making momsicles:

    There are other suggestions in the comments section. One of the moms says she breaks the frozen milk with a hammer and put milk cubes into her child’s cereal every morning.

    Hope this helps. I’ve never had much milk to put in the freezer but I can imagine how frustrating it can be to discover that all those milk would be useless. My milk also has a soapy taste after 24 hours in the fridge but since I feed pumped milk (during the night) to my baby daily as a supplement it has not been an issue for me.

    • Rebekah says

      Thanks for the suggestions, Selda. I’m not sure “momiscles” are a good alternative for milk effected by excess lipase activity because they would still taste bad.

  18. Tricia says

    I’m pretty sure after reading this that I have this issue. My son literally spit milk in my face after it had been refrigerated a couple of days. I decided to taste it and couldn’t believe how bad it tasted! I thawed out my oldest bag of milk (a month old) and it has the same vomity taste. I’m so devastated to figure this out because I have forceful letdown and pumping makes it worse. The few bags I have we’re so hard to get and I can’t believe they’re wasted. Time to start experimenting to see how long it stays fresh. Thank you so much for these posts and all the support you give your readers!

    • Rebekah says

      Oh goodness, Tricia. I am so sorry. I know how frustrating this can be. Let me know if you come across any questions and you experiment with your milk. You can do this, mama! Good luck!

      • Tricia says

        Thanks Rebekah! I’ve finished my experiment with fresh milk (2 days til yuck), and am still working on my scaled milk (3 days and counting!). Luckily my little one is teething and went on a mini-nursing strike. So I’ve been pumping a lot and my overactive breasts have produced extra milk! So to the stove it goes for a redo on my freezer stash. A small victory for what was a very bad day. :)

        • Rebekah says

          Tricia, if you find that scalding works well for you, then you might want to try the bottle warmer method. I think it is easier than needing to “babysit” your milk on the stove.

  19. Sarah says

    Where were you in 2009! I had this issue and it was really hard to find anyone blogging about it. I did the scalding with a bottle warmer right after I pumped. I wish I had thought to do trials with doing it all at home each evening to see if that worked. I have a two month old and have started freezing some milk and am scared to pull it out. I don’t know if your milk is the same with every child or if the over active lipase is just a sometimes thing. Am going to pull some out tonight to give it a try!

  20. Sarah says

    The milk that was two months old was “bad”. But, the milk that was a little less than a month old was ok. Have not tried the fridge test to see how long it will last. Still just trying to get my almost three month old to drink from the bottle! I will just be pumping each day for the next and if we have supply issues that can’t be resolved, will supplement with a little formula. Hoping that won’t happen though.

  21. Carrie says

    Hi Rebekah, just wanted to chime in and thank you for all of this info on lipase. It wasn’t until my second child that I learned my breast milk had the lipase issue. It didn’t bother my son, but my daughter does seem to be affected, and like you, I too have a huge inventory in the freezer, that I did not scald. I will hold onto it and see if she will take it later, if not I will definitely donate it. The bottle Warmer tip is a huge help, will definitely try that. I’ve been scalding each night before I go to bed, not fun, but for s good cause, right?!

    • Rebekah says

      It is NOT fun! It is just one more thing on a never ending to-do list. Hang in there though, Carrie. It is only for a short season of life, right?

  22. April says

    Hi rebekah,

    So finally figured out that I have high lipase activity. My froZen breastmilk smells like vomit and seems like its rancid. Is this milk still safe to drink?! I followed proper storage measures, so don’t think it’s a storage issues. If it is still safe to drink? , I think I’d like to donate my milk since I have over 400 ounces pumped and frozen. It’s devastating to think of all that time and energy and middle of the night wake ups I did to pump extra milk. Sigh. But wasn’t sure if it’s safe to drink since it smells horrible/rancid/pukey. Not soap like at all.

  23. Sarah says

    Hi Rebekah,

    I am a new mom and discovered my milk too tastes nasty after about 30 minutes after pumping :( it tastes more metallic and sour, rather than soapy. I have put it in lansinoh bags to freeze and plastic bottles in the fridge…all the same. I tried scalding it on the stove and that didn’t seem to help. Maybe I didn’t scald it long enough? My daughter seems to be very picky and took a half formula/half gross breastmilk bottle ok, but not great. Really disheartening. I too have tons stored in the freezer and produce a lot. Really just don’t know what to do at this point :(

    • Rebekah says

      Sarah, did you use a thermometer to monitor the temperature? Do you have a knowledgeable lactation consultant that you can talk to?

      Don’t give up, Sarah. You will get through this.

  24. Sarah says

    Thank you Rebekah! No I did not use a thermometer. I watched a video on another blog…basically bringing it to a full simmer, cool down, and store. I am wondering if I should try your method. I would need to buy everything, as I don’t have on hand. I talked to the lactation consultant where I delivered and she basically led me to some blogs and didn’t have any new information for me as I had already been researching. :/

    • Rebekah says

      If you plan to breastfeed/pump for even a month longer, I would say investing in a bottle warmer is worth it. The bottle warmer method is just so much easier! Plus I feel like you have more control over the temperature. On the stove it can quickly go from scalding to a full boil.

      Keep me posted. And again I will say, you can do this!

      Don’t throw away your frozen milk. You can donate it.

  25. Sarah says

    Thank you for your encouragement…it is nice to have someone understand! So do you think I probably have a lipase issue? I couldn’t imagine it being anything else. Also, does scalding always work? I didn’t know if there were any chances it wouldn’t work for some women? Also, does the milk usually stay “fresh” after scalding in the freezer or fridge? Thank you :)

    • Rebekah says

      Sarah, You can “test” your milk for excess lipase activity. Pump a small amount 1/4 oz is enough. Taste it right away and see how it tastes fresh. Then taste it again every couple of hours. If the taste changes, then it is probably a lipase issue. My milk tastes bad after 24 hours. Some women notice a change after 4.

      The scalded milk should stay fresh like “normal” milk (6-8 days in the fridge).

      Scalding seems to work for women, but there hasn’t been official research done.

  26. Sarah says

    Ok, thank you Rebekah for your helpful information! We are going to try scalding with your method and see if it works! I definitely realized I have a lipase issue!

  27. Kara says

    I just tired my milk for the first time ever my baby is almost 6 months old I always thought it would be weird to try my own milk but she always has a hard time taking out of a bottle now I know why this is nasty can use scaled after its frozen why will that not do the same thing?

    • Rebekah Hoffer says

      Scalding the milk will not reverse the bad taste. That is why you need to scald the milk BEFORE the taste forms.

  28. Stephanie says

    Hi Rebekah, have you ever noticed a difference in how long your unscalded milk stays “good” in the freezer based on whether you put it directly in the freezer versus putting it in the fridge for a few hours first? I’m not done testing, but it seems like maybe my lipase activity is slower when the milk is in the fridge for a while before freezing. The only reason I can think of for this would be that when it sits in the fridge the fat separates to the top and then less fat is in contact with lipase while it’s frozen. Thoughts?

    • Rebekah Hoffer says

      Stephanie, that is an interesting theory. I’ve never tested it myself. Once I realized I had this problem, I scalded all of my milk and didn’t put any unscalded milk in the freezer.


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