Breast milk is often called “liquid gold” because it’s filled with antibodies, healthy fats, enzymes, and vital nutrients designed to support your baby’s growth and immunity. One of these natural enzymes is lipase, which plays a key role in helping your baby digest and absorb fats. However, for some mothers, high levels of this enzyme—commonly referred to as Lipase Breast Milk—can cause changes in the taste and smell of stored milk.
If you’ve noticed that your refrigerated or thawed breast milk smells soapy, metallic, or sour, it may be due to high lipase activity. While the milk is still safe to feed, some babies may reject it due to the altered taste. This can be frustrating for moms who pump and store milk regularly.
What Is Lipase in Breast Milk?
Lipase is a natural enzyme found in all breast milk. It plays an important role by breaking down fats, making it easier for babies to digest. Lipase helps babies absorb nutrients like essential fatty acids, which are crucial for brain development and growth.
For most moms, lipase works quietly in the background. But for others, this enzyme continues breaking down fats even after milk is expressed and stored. This can lead to noticeable taste and smell changes, especially in refrigerated or frozen milk.
This is especially important for mothers using freeze-dried breast milk powder for travel or long-term storage.
How Does Lipase Affect Stored Breast Milk?
Lipase activity increases over time when milk is stored. This enzyme continues to break down milk fats, which can change the way your breast milk tastes and smells. While the milk is still safe and nutritious, babies who are sensitive to taste may refuse it.
Common lipase-related changes include:
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A soapy or metallic smell
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A sour or rancid taste
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Thinner texture than fresh milk
These changes usually happen after milk has been refrigerated for a few hours or frozen and thawed. Fresh milk rarely shows these signs.
How to thaw frozen breast milk properly can help reduce unwanted odors and preserve nutrients.
Is High Lipase Milk Safe for My Baby?
Yes. Even if your breast milk smells or tastes different due to high lipase activity, it is still safe to feed your baby. The nutrients remain intact, and there’s no health risk.
However, some babies may reject the milk if they are sensitive to taste changes. In those cases, there are simple steps you can take to reduce the effects of lipase.
Considering other feeding options? Here’s a detailed comparison between breast milk and formula to help you decide.
How to Test for High Lipase in Breast Milk
If you suspect high lipase activity, do this simple test at home to confirm how your milk reacts over time:
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Express fresh milk and store part of it in the fridge using a clean, sealed container
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Taste and smell it at different times — after 1, 6, 12, and 24 hours
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If the milk develops a soapy, metallic, or sour odor, or tastes unusual compared to freshly pumped milk, you likely have high lipase milk
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Repeat the same process using frozen and thawed milk
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Compare each sample to fresh milk for any strong changes in smell or taste
Use a small amount of milk for this test so you don’t waste your main supply. If you find consistent changes in smell or flavor after storage, it’s a good idea to start scalding or adjusting how you store your milk.
What to Do if Your Milk Has High Lipase
If your baby refuses stored milk due to taste, you can use a technique called scalding to deactivate the lipase enzyme before freezing.
Steps to scald milk:
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Warm freshly expressed milk in a clean pan on the stove
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Heat until small bubbles form around the edges (about 82°C or 180°F)
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Do not boil
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Cool quickly and store in clean containers before freezing
Scalding stops lipase activity, preserving the original taste and making milk more acceptable for your baby.
Pros and Cons of Scalding Milk
Pros
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Prevents soapy or metallic taste
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Helps babies accept stored milk
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Extends the freezer life of expressed milk
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Allows better use of stored milk instead of discarding it
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Gives peace of mind for moms who need to build a freezer stash
Cons
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Slight loss of heat-sensitive nutrients
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Extra time and steps for pumping moms
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This must be done immediately after expressing
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Requires careful temperature monitoring to avoid overheating
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It may not be practical when pumping on the go or at work
If you only store milk occasionally or your baby doesn’t mind the taste, scalding may not be necessary. But for moms with high lipase issues and long-term storage needs, it can be a helpful solution.
Preventing Lipase Taste Changes Without Scalding
If you prefer not to scald your milk, here are some helpful tips:
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Store milk in the fridge for shorter periods
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Freeze milk as soon as possible after expressing
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Use frozen milk within 1 to 2 months for the best taste
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Mix fresh and frozen milk to mask taste differences
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Try different thawing methods (like slow thawing in the fridge) to minimize odor
Planning a trip? Read our guide on travelling with breast milk for safe and convenient storage options on the go.
Feeding Tips for Babies Sensitive to Lipase Milk
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Try offering the milk slightly warm—it may reduce the taste sensitivity
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Mix lipase milk with freshly expressed milk in small amounts
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Use a bottle with a slow-flow nipple to keep your baby focused on feeding
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Introduce lipase milk when your baby is calm and not overly hungry
Always make sure the milk temperature for baby is just right for safe and comfortable feeding.
When to Talk to a Lactation Consultant
If milk refusal continues or you’re unsure how to manage high lipase breast milk, consider talking to a lactation consultant. They can:
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Help confirm high lipase activity
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Offer storage and scalding guidance
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Suggest alternatives like freeze-dried milk or donor milk if needed
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Provide emotional support and reassurance
Conclusion
Dealing with high lipase breast milk can be frustrating, but it’s manageable. Understanding the lipase enzyme effects and knowing how to handle milk taste changes can make feeding easier for both you and your baby. With methods like scalding, mixing, or adjusting storage times, you can continue giving your baby the nourishment they need, even if they’re picky about taste.
Every mom’s journey is different, and every baby is unique. Stay patient, try different solutions, and don’t hesitate to reach out for help. Breast milk—no matter how it’s stored—is still a powerful and healthy source of nutrition.
Frequently Asked Questions
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What causes high lipase in breast milk?
It’s a natural variation. Some moms produce more active lipase than others. There is no way to control how much lipase your body makes—it’s not related to diet, hydration, or health. It simply depends on your biology. Lipase itself is beneficial because it helps babies digest fat better.
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How soon does the taste change happen?
For some moms, milk tastes different after just a few hours in the fridge. For others, it may take 12 to 24 hours or only happen after freezing and thawing. It’s best to test a small batch of stored milk to see how your milk reacts over time.
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Is high-lipase milk bad for my baby?
No. It’s still safe and full of essential nutrients, antibodies, and healthy fats. The milk remains beneficial even if the taste is off. The only concern is that some babies may be more sensitive to the flavor and might refuse it at first.
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Will scalding damage the milk?
Scalding slightly reduces some heat-sensitive nutrients, like certain enzymes and vitamins, but overall, it keeps most of the milk’s benefits intact. It’s one of the best options if your baby refuses previously frozen milk due to taste changes.
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Can I mix scalded and unscalded milk?
Yes, but only after the scalded milk has completely cooled. Mixing hot milk into cold or frozen milk can raise the temperature and increase the risk of bacterial growth. Always chill scalded milk first before combining it with previously stored milk.
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Does high lipase mean I’m unhealthy?
Not at all. High lipase levels are not harmful to you or your baby and have nothing to do with your health, diet, or milk quality. Lipase is a beneficial enzyme—it just becomes an issue when its activity affects milk's taste after storage.
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Can I donate high-lipase milk?
Most milk banks accept milk with high lipase as long as it passes safety screenings and is properly stored. However, some banks may do a taste or odor check, and a few recipients may have preferences regarding milk flavor, especially for medically sensitive babies.
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What does high lipase milk smell like?
It often smells soapy, metallic, or slightly fishy. These changes are more noticeable after refrigeration or thawing. The milk may look normal, but it can have a strong odor that’s different from freshly expressed milk.
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Is there a way to remove the smell from thawed milk?
Unfortunately, no. Once the taste or smell has changed, it cannot be reversed. Scalding milk before freezing is the only known method to stop the lipase activity and prevent future odor or taste changes.
- Will my baby outgrow sensitivity to lipase milk?
Possibly. Some babies adjust to the taste over time, especially as they get older and start eating solids. If your baby continues to refuse it, try small amounts mixed with fresh milk, or use it in cereals or purees to mask the taste.