How to remove lactose from milk: A complete guide to DIY and commercial methods

January 1, 2026 •

3 min read

An estimated 65% of the global population has a reduced ability to digest lactose after infancy. For those with this intolerance, it is possible to remove lactose from milk, enabling them to enjoy dairy products without digestive discomfort. The primary methods involve using the natural enzyme lactase or advanced filtration processes.

Quick Summary

This guide details the process of creating lactose-free milk, explaining both the enzymatic hydrolysis method used commercially and the straightforward process for home preparation. It compares techniques and discusses the resulting flavor profile.

Key Points

Enzymatic Hydrolysis: Adding the lactase enzyme is the primary way to break down lactose into simpler, more digestible sugars.
DIY Simplicity: Making your own lactose-free milk is an easy and cost-effective process using commercially available lactase drops and refrigeration.
Altered Flavor: The resulting lactose-free milk will have a sweeter taste than regular milk due to the presence of glucose and galactose.
Dual Commercial Process: Large-scale production combines ultrafiltration to remove some lactose with enzymatic treatment to break down the rest for precise results.
Nutritional Equivalence: Lactose-free milk retains the same essential nutrients as regular dairy, such as protein and calcium.
Intolerance vs. Allergy: It's crucial to remember that lactose-free milk is still dairy and is not a substitute for those with a milk protein allergy.

Understanding Lactose and Lactase

To understand how to remove lactose from milk, it is first essential to know what lactose is and the role of the lactase enzyme. Lactose is a disaccharide, or a complex sugar, found naturally in milk and other dairy products. It is composed of two simpler sugars: glucose and galactose. The human body normally uses the enzyme lactase, produced in the small intestine, to break down lactose into these more digestible components.

When a person has lactose intolerance, their body does not produce enough lactase. This means the lactose isn't properly broken down in the small intestine and instead travels to the large intestine. Here, gut bacteria ferment the undigested lactose, leading to uncomfortable symptoms such as bloating, gas, abdominal pain, and diarrhea. Lactose-free milk is essentially regular milk that has been pre-treated to break down the lactose before it is consumed, thereby preventing these symptoms.

Methods for Making Lactose-Free Milk

There are two main approaches to removing lactose from milk: a straightforward DIY method using lactase drops and the more sophisticated commercial processing used by large dairy companies. Both achieve the same goal, but through slightly different means and with varying results.

Method 1: Using Lactase Enzyme Drops at Home

This is the most accessible method for home use and is very cost-effective. Liquid lactase enzyme drops are widely available at pharmacies and online retailers.

Step-by-step guide to making lactose-free milk at home:

Purchase Lactase Drops: Buy a bottle of liquid lactase enzyme drops, following the specific brand's instructions for storage, usually refrigeration.
Add Drops to Milk: Follow the manufacturer's dosage recommendations. A common suggestion is to add 7-10 drops per liter of milk.
Mix Thoroughly: Gently stir or shake the milk container to ensure the lactase is evenly distributed.
Refrigerate and Wait: Place the milk back in the refrigerator for at least 24 hours. The enzyme requires time to break down the lactose completely. Some guides suggest a longer period for maximum lactose conversion.
Enjoy: The milk is ready to be consumed after the waiting period. You will likely notice a sweeter flavor profile than regular milk.

Method 2: Commercial Ultrafiltration and Enzymatic Treatment

Commercial dairy producers use a more complex, two-step process to create lactose-free milk on a large scale. This method typically results in a product with a more neutral, less sweet flavor compared to the at-home enzymatic process. The process involves filtering milk to remove some lactose, followed by adding lactase to break down the remainder. Pasteurization then kills bacteria and deactivates the enzyme.

Comparison of Lactose Removal Methods


Feature	DIY Method (Lactase Drops)	Commercial Method (Filtration + Enzymes)
Equipment Needed	Standard milk container, lactase drops	Industrial-scale filtration and pasteurization machinery
Lactose Removal	Varies based on dosage and time; typically 70-80% or higher	Precise and nearly complete; verified to be under 0.1%
Flavor Profile	Significantly sweeter due to simple sugars	Milder, more neutral flavor profile
Cost	Cost-effective for individuals, saves money over buying pre-made	Higher initial cost due to manufacturing process, reflected in retail price
Process Time	Requires a 24-48 hour wait period in the refrigerator	Immediate availability for consumer after factory processing

What to Expect with Lactose-Free Milk

Lactose-free milk offers the same nutritional benefits as regular milk, including protein, calcium, and vitamins B12 and D (if fortified). The primary difference is the taste and texture. Because the lactase enzyme breaks down lactose into sweeter-tasting glucose and galactose, the milk has a noticeably sweeter flavor profile. Some people may also perceive a slightly different texture, though this is often minimal. It is also important to remember that lactose-free milk is still a dairy product and not suitable for individuals with a cow's milk allergy. It only addresses the sugar component, not the proteins.

Conclusion

Whether for personal health or cost savings, knowing how to remove lactose from milk provides a valuable and convenient option. The DIY method using lactase drops offers an easy and affordable way for individuals to create their own lactose-free dairy at home with minimal effort. For those who prefer a more traditional flavor and industrial-scale precision, commercial products that utilize a combination of ultrafiltration and enzyme treatment are readily available. By understanding these processes, those with lactose intolerance can continue to enjoy the nutritional benefits of dairy, tailoring the method to best fit their needs and preferences.

Authoritative Outbound Link

For more detailed information on lactose intolerance and the science behind digestion, visit the National Institute of Diabetes and Digestive and Kidney Diseases.

Frequently Asked Questions

No, boiling milk does not remove lactose. Lactose is a sugar that is not destroyed by heat, and only the addition of the lactase enzyme can break it down into digestible simple sugars.

No, lactose-free milk often tastes sweeter than regular milk. This is because the lactase enzyme breaks down lactose into glucose and galactose, which our taste receptors perceive as sweeter than the original lactose molecule.

For optimal results, it is best to add the lactase drops to the milk and refrigerate it for at least 24 hours. This allows the enzyme sufficient time to break down the lactose.

No, lactose-free milk is not suitable for people with a milk allergy. A milk allergy is an immune system response to the proteins in milk, while lactose intolerance is a digestive issue related to the sugar. Lactose-free milk still contains milk proteins.

No, the enzymatic process is unaffected by the milk's fat content. However, some sources suggest full-fat milk may be easier to digest for some lactose-intolerant individuals because the fat slows digestion.

No, not all dairy products contain lactose. Hard, aged cheeses like cheddar and parmesan contain very little to no lactose because bacteria consume it during the aging process. Fermented products like yogurt also have lower lactose levels.

Yes, lactase enzyme drops are considered safe to consume. They contain the same natural enzyme that the human body produces to digest lactose. Always follow the manufacturer's instructions for dosage.

Store-bought lactose-free milk often uses a two-step process involving filtration first to remove some lactose before adding enzymes. This controls the final sweetness. Homemade versions only use the enzyme, leading to a sweeter flavor.