Your breast milk tastes soapy due to high lipase activity, an enzyme that breaks down fats too quickly, especially in stored milk, creating fatty acids that give it a soapy, metallic, or sour taste; it's still nutritious but can be managed by scalding milk before freezing or mixing fresh with stored milk if your baby rejects it.
Soapy-smelling milk Some mothers make milk that has higher-than-average levels of the enzyme lipase, which over time breaks down fat in expressed milk (Mohrbacher, 2010). This fat breakdown can cause cooled or frozen milk to develop a soapy smell and taste.
Is High Lipase Milk Dangerous to Your Baby? Dr. Chang points out that while excess lipase can change the taste of the milk, it does not make it harmful to the baby. In fact, it may even have benefits for your milk.
Breakdown of fats
Lipase in breast milk breaks down fats into fatty acids (a process called lipolysis) and it is these fatty acids that are thought to cause the soapy taste.
Perhaps you've given your pumped milk a sniff test, and you notice that it has a soapy, metallic, or even rancid scent. When breast milk has an unpleasant odor, something called high lipase is often blamed. While high lipase content may be a cause of breast milk with a bad or sour smell, this isn't always the case.
HOW TO PREVENT HIGH LIPASE IN BREASTMILK
Does Your Stored or Frozen Breastmilk Have a Soapy or Metallic Taste or Smell? If you have soapy or metallic tasting breastmilk, this could be a sign of high lipase.
Milk is naturally bubbly when shaken, whether we're talking about breast milk or cow's milk. This is due to the protein content, or lipase, present. The more lipase your breast milk has, the bubblier it may appear as your pumped bottle fills up (especially when combined with a forceful letdown).
Symptoms include:
1. What does breast milk taste like? In general, breast milk is considered normal when it characterizes a pleasant smell, mild taste, neither too salty nor too sweet. Especially when the baby is newly born, the breast milk (colostrum) at this stage is very thick and fragrant, and then it gradually becomes thinner.
The 5-5-5 rule for breast milk is a simple guideline for storage: freshly expressed milk lasts up to 5 hours at room temperature, up to 5 days in the refrigerator, and up to 5 months in a standard freezer, though the CDC notes it can be frozen for up to 12 months for best quality within 6 months. Always label containers with the date and time, use small batches (2-4 oz), and place milk in the back of the fridge or freezer for consistent temperature.
Freezing breast milk does not completely inactivate the lipase enzyme, though it does slow down its activity. While freezing prevents the enzyme from causing a soapy or sour taste immediately, lipase activity can resume upon thawing.
It's important to differentiate between high lipase milk and spoiled milk. Spoiled milk will have a distinctly sour and unpleasant smell, unlike the certain specific aromas associated with high lipase which are metallic, soapy, or fishy.
High Lipase Milk is Safe
The odor might be mild, or it might be pretty strong and unpleasant. It is actually harmless though. It's perfectly safe to use this milk to feed your baby.
Your first milk, colostrum, is less sweet because it's higher in nutrients and protein and lower in fats and lactose. As your mature milk comes in (a few days after birth), it will contain more sugar and taste sweeter.
The rusty color is usually due to mixing of colostrum, or first breast milk, with a small amount of blood [2]. The rusty-colored milk usually appears during the first few days of breastfeeding. In most cases, the syndrome is spontaneously cured within 3 to 7 days after the onset of lactation [2,5].
We are unable to change the composition of your breastmilk and prevent high lipase levels occurring in your breastmilk, but there are treatment methods to manage the lipase in your expressed breastmilk. These involve what we call scalding, or heat treating your milk. This works to inactivate the lipase.
Alcohol consumption: Regular or excessive alcohol intake can irritate the pancreas and lead to both acute and chronic forms of pancreatitis, resulting in elevated lipase levels. High-fat diet: Consuming large amounts of fatty foods can temporarily increase lipase as the body works to digest the fat.
If you do have excess lipase activity in your breast milk, you might notice a difference in its smell and taste after pumping and storing, though how long this takes to develop can vary from person to person. Some possible changes include: Milk that has a soapy smell or taste. Milk that has a metallic smell or taste.
The watery milk is seen at the bottom while the creamy layer is seen on top. If you swirl the milk a few times and it is still separated into 2 layers then that may indicate that it has gone bad.
How much milk does a newborn need? You may find that your baby starts feeding with regularity and zero fussiness. However, if your baby's feeding habits change to the point where he is wailing and fussing during feedings, then you may have too much breastmilk for your newborn.
Gen Z isn't drinking as much milk due to health concerns (lactose intolerance, acne), ethical/environmental worries about dairy farming, the influence of social media promoting alternatives, increased awareness of dairy's downsides, and a desire for healthier, more personalized options like plant-based milks, though they still enjoy other dairy products like cheese and yogurt. They question traditional health advice and are swayed by peer culture and eco-consciousness, leading them toward alternatives for taste, values, and lifestyle fit.
High lipase activity in breast milk can cause the milk to develop a soapy or metallic taste and smell when stored. This change occurs because the enzyme breaks down the fats in the milk more quickly, releasing fatty acids that alter the milk's flavor.
A very high level of lipase is usually a sign of acute pancreatitis. Higher than normal levels of lipase may be caused by: Diseases of the pancreas, including a blocked duct (tube), or pancreatic cancer. Chronic kidney disease. Peptic ulcer.
if your baby is at least 6 months old, adding one to two drops of alcohol free vanilla extract per ounce of breastmilk can help improve the taste of high lipase breastmilk.