If you are struggling with breast milk that smells off or sour despite following proper storage guidelines, then you might be dealing with excess lipase.
Having excess lipase isn’t the end of the world and there are a few things you can do to help keep the sour smell and taste from affecting your breast milk.
This guide will help you understand what excess lipase is, how you can avoid the change in taste by scalding breastmilk, and what to do if your baby won’t take the milk.
Excess Lipase and Scalding Breastmilk
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There are a lot of things that I was not prepared for as a pumping mom. Excess Lipase was one of them…
As a working mom who pumped 7-8 times a day to provide enough milk for my baby, you can imagine my shock and horror the first time I thawed a bag of frozen breast milk from my freezer stash (that I worked tirelessly to build before returning to work) and it smelled off…
I had followed all the appropriate storage guidelines. It wasn’t even close to being expired. The freezer bag has no holes and wasn’t compromised in any way.
What did I do wrong???
Being uninformed, I did what any paranoid first-time mom would do, I dumped that entire bag of breast milk (5 WHOLE OUNCES!). Ouch.
I thawed a second bag. Same issue…
I immediately started to worry that something happened to my freezer. Perhaps my milk thawed without me realizing it and then refroze. Maybe ALL the milk I had stored (500+ ounces) had gone bad!?
I wanted to cry.
That was when it was suggested to me by a friend to look up excess lipase and scolding breastmilk.
What is Excess Lipase?
Lipase is an enzyme found in breast milk that helps aid in breaking the fat down so that baby can digest it easier. When the lipase is present in excess, that process happens much more rapidly causing the breast milk to taste different and smell sour.
Most moms, like myself, find that freshly expressed breast milk is fine. Frozen breast milk was the culprit for me. I could store fresh breast milk in the fridge for days and it would taste and smell normal. But frozen milk was another story.
Some moms find their freshly expressed milk turns sour tasting after just a few hours. It all depends on the level of the excess lipase.
How to Tell if Excess Lipase is the Issue?
If you have followed all storage guidelines correctly, then excess lipase is most likely the issue.
Here is a quick test you can do:
- Pump fresh milk
- Pour that milk into two store bags
- Put 1 storage bag into the freezer and one in the refrigerator
- Leave for 24-48 hours.
- Thaw the frozen milk
- Test both samples of milk
- If the frozen sample smells off, then it is most definitely a high lipase issue
Having excess lipase does NOT mean the breastmilk smells rancid. This is more of a soured or soapy smell/taste. Rancid smelling breastmilk might mean you had an issue with storage temperature or the milk is outdated.
Is Excess Lipase Breast Milk Safe for Baby to Drink?
Despite smelling slightly off and assuming proper storage guidelines have been followed, breastmilk with excess lipase is completely safe for your baby to drink.
If your baby takes the milk fine, then don’t worry about the excess lipase. There is nothing that you need to do. Count yourself lucky!
However, some babies will refuse the milk due to the altered taste. If this happens, you can do a few things.
If Baby Refuses the Breast Milk, You Can:
- Pump and feed only freshly pumped milk (that’s tough for moms who work or pump exclusively)
- Scald the Breast Milk (more on that below) before storing
- To save your current breastmilk stash, you can mix (cooled) scalded milk with fresh or frozen milk that contains the high lipase in hopes it will help your baby take it. The ratio will be trial and error.
- If mixing doesn’t work, consider donating the milk to a milk bank as excess lipase is not typically an issue from milk banks.
Scalding Breastmilk
Scalding breastmilk is your best bet for solutions if you want to pump and freeze breast milk when dealing with excess lipase.
Unfortunately, this is not an option for breastmilk that has already been cooled and stored. You need to scald freshly pumped milk.
Steps for Scalding Breastmilk:
- Soon after expressing breastmilk, transfer milk to clean saucepan on the stove
- Heat the milk to about 180 F (82 C) or until you see small bubbles around the edge of the pan
- DO NOT bring to a rolling boil!
- Quickly remove from the heat and quickly cool the milk
- Store (freezer or refrigerator)
While scalding breastmilk does damage some of the anti-infective properties and kill off some of the nutrients, this isn’t a huge issue unless all you ever feed your baby is scaled milk. Make sure they are either breastfeeding or getting freshly pumped milk as well.
Using a Bottle Warmer to Scald Breastmilk
One of the biggest issues I had while working was not having access to a stove to scald breastmilk. This meant anything I pumped at work could not be frozen. That was tough.
One tip I learned fairly quickly was to scald my milk using a standard bottle warmer. It would take less than 8 minutes to scald the milk and clean everything up. Add my 15-20 minute pumping session and I was done in less than 30 minutes.
What You Need to Scald Breastmilk in a Bottle Warmer:
- A Bottle Warm without auto-shutoff feature – I used the Philips Avent Fast Bottle Warmer its one of the few on the market that does not have the auto-shutoff.
- Stainless Steel Bottle – I hate heating the plastic storage containers and storage bags to such a high heat. Stainless steel bottles were my goto. I used the Kid Kanteen Baby Bottles.
- Access to Ice & Container – My office had an ice maker and that was super convenient! Bringing ice from home is another option. Have a container wide enough to give the bottle an ice bath.
- Digital Thermometer – Make sure it’s food grade! I used this one – here.
- Milk Storage Bags – You will need to transfer the milk into storage bags after it is scalded.
Philips Avent Fast Bottle Warmer
Steps for Scalding Breastmilk in a Bottle Warmer:
- Express Milk
- Prep a container with ice and water for an ice bath to dunk the scalded breastmilk bottle into
- Transfer milk to stainless steel bottle and put the bottle cap on but leave the nipple off
- Add water to the bottle warmer and place bottle in the warmer
- Place the thermometer directly into the milk
- Turn on the bottle warmer and watch the thermometer very closely
- As soon as the milk temperature hits 180 F, quickly remove the bottle and place it in the ice bath being careful not to spill the milk or get ice water in the milk bottle
- Once the milk is relatively cool, transfer the milk to a storage container or bag
- Refrigerate or Freeze Breastmilk
You can See How Easy Using a Bottle Warmer is:
Scalding breastmilk may seem like a hassle since you are adding extra steps in addition to pumping but when dealing with excess lipase in your breastmilk it is by far the best way to avoid the altered taste in your breastmilk.
Breastfeeding as often as you can and feeding your baby freshly expressed breast milk when convenient, will help save you the trouble but in order to build a freezer stash, scalding breastmilk is the best way to remedy high lipase.
Have questions or comments? Drop me them below! I would love to hear from you!
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Keep Reading –
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I added 2oz of freshly expressed breastmilk to 0.5 oz of cooled bm without chilling it first. I know is not good to do this, but I was sorting the containers and when I realized what I did it was too late..
My son will eat it today while I am at the docto’s, would it be ok, or should I dump the 2.5 oz intesad?
Thanks in advance.
Hi Eliza,
You should be fine to feed the milk. If it smells sour, then toss it but it likely will be fine since it was such a small amount. And yes, it is good practice to cool the milk first before adding it to previously cooled milk. =-)
Do you have to being the temp to EXACTLY 180 degrees? What if it gets a little higher? I scald in a bottle warmer but it’s not an open top one so I can’t monitor the temperature as it’s being heated so I have to guess how much time to heat it for and sometimes it gets into the 190s
The idea behind not going over 180 degrees is that you want to protect as much of the nutritional value of the milk as possible by not heating it more than necessary. 180 degrees is the point when the enzymes are broken down and going hotter will only further damage the good properties of the milk. I would say do your best to monitor how long it takes to reach that temperature and try your best to stay around 180.
This might be a dumb question, but here it goes… is it ok to put milk that had just been scalded immediately into freezer bags? I have been using a small funnel to pour my milk from the sauce pan I use to scald it directly into the freezer bags. Then I cool them in ice water before putting them in the freezer. Is it ok to put milk that hot into a plastic bag? I feel like this is such a silly question but I can’t find an answer to it anywhere else!
I personally would not. You are right that there is not much info on max temp the bags can handle… There are warnings not to overheat the milk but this is due to the potential to damage the nutritional content of the milk.
The reason I say that I wouldn’t is that I fear it would damage the bag and then would I end up with a leaky bag. You don’t need to completely cool the milk. Just to where it is warm, not hot.
And this wasn’t a silly question at all!
Hi,
I was wondering what size bottles you used in the warmer. I would like to buy the 9oz but need to make sure it will fit. Also, do you think you could do this without a thermometer? I travel for work so I don’t think I can bring a meat thermometer through TSA.
Thank You,
Kathryn
I have used both the Avent bottle and Dr Browns in the Avent bottle warmer. But when using it to scald milk, I like using the Kid Kanteen stainless steel ones. I don’t like the idea of heating the plastic bottles to that temp time after time. But you certainly could. All these bottles are wide-mouthed bottles and fit fine. The opening of the bottle warmer is 78mm. Most standard bottles on the market should fit.
As for the thermometer. You might be able to find a different type than the one I used. I personally have not tried scalding without one. You would really have to watch it. Maybe you can scald some bottles at home and time it and watch it to see how it looks and try to replicate that without a thermometer. I would be very careful trying this, however. It could end up boiling too much or not enough.
Hi, thank you for sharing your experience. So what did you do with your previous stash that your baby didn’t take? Can you scald thawed milk? Also, can I use a glass bottle rather of a stainless steel?
Great questions!
So with my previous stash, I would mix an ounce of it with fresh milk and he took it fine. This slowly used that milk up. I also used some for a milk bath when he got a rash since it was close to expiring and there was no way to give it to him fast enough! It was a huge bummer that he would not take the milk. If your baby will take it, then I wouldn’t even bother to scald the milk but unfortunately, mine wouldn’t.
Scalding thawed milk won’t reverse the excess lipase. The reason you need to scald fresh milk is to slow that process down and keep it from advancing. So you can’t undo it once it’s already affected the milk. Make sense?
As for glass bottles… I personally have not tried them. I really think this is going to depend on the brand and if it is made for the high temp exposure. I would be concerned about it shattering. I would do your homework on this before trying it. But I think glass bottles are amazing!
Can I scald milk that has been in the fridge? For instance, if I pump at midnight, can I put it in the fridge and scald in the morning?
Hi Samantha,
It is ok to scaled milk that has been cooled (not frozen though). The results of this will vary from mother to mother. Since the lipase can begin to change the taste of the milk at various times for each individual, many moms find they need to scald right away. Others can wait a few hours. I would recommend you give it a try and see what happens. Hope this helps!
Thank you for this! I had a lot of milk in my freezer but my almost 4 month old is not taking it. I tried my frozen and fresh and they do taste different but the frozen doesn’t taste “bad” just different. I attempted to scald my first bit of milk tonight. I think I will eventually order the items you used for when you are at work because that is when I pump the most. Few questions;
How long would you wait for the milk to “cool”?
At work did you put it straight into bags into a cooler to take home and then into the freezer?
Even when you were home would you scald it using the bottle warmer?
I have enough fresh for him but I’m just worried if I ever need to be away or I get sick or my supply drops then I would like to have some backup so I want to attempt this to see if it will help him take some frozen milk!
Hi Alex! Great questions!
Q: How long would you wait for the milk to “cool”?
A: If you are talking about scald milk, I would leave it in the refrigerator for a few hours. I would not put scald milk into freezer bags and into the freezer because I would be concerned about the freezer bag leaking due to the heat. It doesn’t have to be cold before going into the freezer as you can put freshly pumped milk directly into the freezer without issue. I just wouldn’t put scald milk directly in the freezer. And you CANNOT combine cold milk with warm milk. You need to cool them to the same temp before combining them. Here is a good article that covers all that and more regarding storage guidelines for breast milk (see that here).
Q: At work did you put it straight into bags into a cooler to take home and then into the freezer?
A: So, once I cooled the milk in the stainless steel bottle after scalding it (with the ice bath), then I would transfer the milk to storage bags. Depending on what office I was in for the day, I would carry a cooler with ice packs and then pop the milk in the freezer when I got home. Or I would store a small cooler lunch bag with the milk storage bags in it in the office refrigerator and then freeze when I got home. Either way, it was chilled and then frozen when I got home.
Q: Even when you were home would you scald it using the bottle warmer?
A: No, I kept the bottle warmer at work. I hardly ever scald the milk I pumped at home since I usually used it right away or stored it in the refrigerator for a day or so. Now, when I was building my freezer stash before going back to work or if I needed to freeze the milk I pumped at home, then I just used a saucepan. I suppose I could have bought a second one and it might have been nice to have a bottle warmer at home to use anyway, but I didn’t.
I hope this helps!
Can I scald milk, refrigerate and add to other scalded milk or do I need to put each in their own freezer bags?
Hi! Yes, you can add cooled milk to other previously cooled milk regardless if it was scald or not! It is important that they are both cooled before mixing them, however. You will also have to use the date of the oldest milk for the expiration. You can see a full list of those expiration guidelines, here. I hope this helps!
Hi, thanks for this brilliant info!
If I scald then store in the fridge, how long is the milk food for and can it be reheated. Going back to work next month and plan to do this: pump at work, immediately scald, store in fridge at work, take home in cooler box at the end of the day and put in fridge at home. Then planned to send this milk to nursery with baby the day after. So basically every day I will pump the milk for the next day… will this be ok?
Yes, it will be fine.
You can follow these same guidelines, here. Freshly expressed (even after you scald it initially) will last 3 days (up to 8 depending on temp). If the milk was previously frozen and then thawed, then it is good for 24 hours.
On a side note, unless you have a super high existence of lipase, you may not have to scald the milk in your case. Most moms don’t find their milk is effected after just a day or two in the fridge. Other moms might see the change happen in a matter of hours. If you haven’t already tested this with your fresh milk without scalding, you might want to. Just wanted to throw that out there! It can take time for the enzyme to break down the milk fat (thus changing the smell and taste). Hope this helps!
Thank you so much for this post! I believe that my breastmilk contains excess lipase and this was by far the easiest steps to follow regarding scalding breastmilk. You mentioned that as long as my baby does not get scalded breastmilk all the time, then it’s okay. But I’m wondering how much scalded breastmilk can I give him in 1 day. He usually takes 30-32 oz of breastmilk a day. Also, if I manage to make my freezer stash last until he turns 1 (cause I plan on pumping for 1 whole year), is it okay to give him scalded milk all the time since he’ll be eating solids and will get some nutrients there? Thank you in advanced!
Great question! I think what you need to consider is the age of your baby. A 6-month-old vs an 11-month-old is a big difference. When you scald breastmilk you damage some of the nutritional and antibody properties of the milk. A 6-month-old is not eating enough variety of food to make up for this lack of nutrition. A better solution would be to freeze some of your milk and then use the rest to mix with the frozen.
So let’s use your 30-ounce example: I typically freeze milk in 2oz or 4oz increments, so what I would do is freeze 16oz, and put 14oz of fresh milk in the refrigerator for the next day’s bottles. Then thaw 16oz from your freezer stash to add to the 14oz of fresh milk (to make 30 oz total) when you are preparing bottles for that day. You don’t need to mix the fresh and frozen (meaning it’s ok to feed one bottle of frozen and one fresh), just as long as their daily intake for long periods of time is not all scalded frozen milk. Does this make sense?
If your baby is close to a year old, then they likely are eating enough variety of foods that you don’t need to worry so much about making sure they are getting fresh milk. I hope this helps!