Does Straining Yogurt Remove Lactose? The Facts on Lactose and Yogurt

December 15, 2025 •

2 min read

Straining yogurt does remove a significant portion of lactose, though it does not eliminate it entirely. The amount of lactose in yogurt is also reduced during the fermentation process by live cultures.

Quick Summary

The straining process, especially in Greek yogurt, reduces lactose levels by removing whey. Fermentation and probiotics further aid digestion. However, yogurt is not entirely lactose-free, especially for those highly sensitive.

Key Points

Partial Removal: Straining reduces, but does not eliminate, lactose from yogurt.
Lower Content: Strained yogurts like Greek yogurt have less lactose than regular yogurt.
Probiotic Benefits: Yogurt's live cultures help digest lactose.
Individual Tolerance: Sensitivity to lactose varies among individuals.
Lactose-Free Options: For no lactose, choose products specifically labeled as such or use lactose-free milk.
Fermentation Time: Longer fermentation further lowers lactose content.

The Role of Straining in Reducing Lactose

Yogurt production involves fermentation, where bacteria convert lactose into lactic acid, affecting the final lactose content. Straining, used to make Greek yogurt, concentrates the curd by removing whey, which contains lactose and water-soluble nutrients. This process results in a thicker yogurt with reduced lactose.

How Much Lactose is Removed?

The amount of lactose removed depends on the extent of the straining. For example, a 6-ounce serving of regular yogurt can have 10–12 grams of lactose, whereas the same serving of Greek yogurt may have as little as 4 grams. However, yogurt still contains some residual lactose unless specifically labeled as 'lactose-free'.

Probiotics and Their Contribution

Probiotic bacteria in yogurt further assist in digestion. These live cultures produce lactase, which helps break down remaining lactose, reducing digestive issues. This makes probiotic-rich yogurts, particularly strained varieties, a more tolerable dairy option for many.

Regular Yogurt vs. Greek Yogurt: A Comparison

Here is a comparison of plain regular yogurt and plain Greek yogurt:


Feature	Regular Yogurt	Greek Yogurt (Strained)
Lactose Content	Higher (10-12g per 8oz)	Lower (4-9g per 8oz)
Protein	Lower	Higher (often double)
Texture	Thinner	Thicker
Tanginess	Less tangy	More tangy
Whey Content	Higher	Lower
Carbohydrates	Higher	Lower

Additional Factors Affecting Lactose Levels

Several factors besides straining affect the final lactose content:

Fermentation Duration: Longer fermentation allows bacteria to consume more lactose, reducing the final concentration.
Probiotic Presence: Not all yogurts have live cultures. Look for the 'Live and Active Cultures' seal.
Thickeners and Additives: Some yogurts use thickeners instead of straining, which might not reduce lactose as effectively.
Type of Milk: Lactose content can vary based on the milk used (cow, goat, sheep).

Making Your Own Lower-Lactose Yogurt

For greater control over lactose levels, you can make your own strained yogurt at home. Start with regular yogurt containing live cultures and strain it further using a cheesecloth or fine mesh sieve. The longer the straining, the lower the lactose content. Alternatively, use lactose-free milk.

Conclusion: Does Straining Yogurt Remove Lactose?

Straining yogurt does reduce lactose, making products like Greek yogurt a more digestible option. Bacterial fermentation and straining both play a role. However, suitability depends on individual lactose sensitivity. For severe intolerance, lactose-free options or homemade yogurt from lactose-free milk are the safest choices. For others, the lower lactose and added probiotic benefits can be beneficial.

For more information on the benefits and production of Greek yogurt, consult sources like the U.S. Dairy.

Frequently Asked Questions

No, Greek yogurt is not lactose-free, though the straining process reduces the lactose amount. Only products labeled 'lactose-free' are truly free of lactose.

Straining removes the whey, a liquid containing a significant amount of lactose.

Many people with mild to moderate lactose intolerance can consume Greek yogurt due to its lower lactose content and live cultures.

Greek yogurt has less lactose than regular yogurt because of the straining process, typically about half the amount.

Yes, probiotics produce lactase, an enzyme that helps break down lactose.

Yes, longer fermentation allows more lactose to be consumed by the live cultures, reducing the lactose content.

Use lactose-free milk, which is pre-treated with lactase, to make yogurt at home.