How to Get Lactose Out of Yogurt

According to the National Institutes of Health, approximately 65% of adults worldwide have a reduced ability to digest lactose after infancy. For those with lactose intolerance, consuming yogurt often leads to discomfort, but with a few simple techniques, you can learn how to get lactose out of yogurt and enjoy its creamy texture and probiotic benefits without the side effects.

Quick Summary

This guide details two primary methods for significantly reducing lactose content in yogurt: extended fermentation and straining to create Greek yogurt or labneh. Both techniques leverage natural processes to make yogurt more digestible for those with lactose sensitivity. Practical steps and tips are provided for each approach.

Key Points

• Extended Fermentation: Ferment yogurt for 24 hours to allow live cultures to consume a significant amount of lactose, resulting in a tangier, low-lactose product.

• Straining Yogurt: For Greek-style yogurt or labneh, strain the yogurt to remove lactose-containing whey, which also thickens the consistency.

• Combine for Maximum Reduction: For the lowest lactose content, first, ferment for 24 hours and then strain the finished yogurt to remove residual whey.

• DIY vs. Store-Bought: Making your own low-lactose yogurt offers more control over the final lactose content and probiotic level than commercially available options.

• Choose Your Starter Wisely: Use a high-quality plain yogurt with live, active cultures as your starter. For a homemade product, avoid ultra-pasteurized milk.

• Don't Discard the Whey: The liquid whey strained from yogurt is rich in nutrients and can be used in baking or other recipes, making it a zero-waste process.

Extended Fermentation: The 24-Hour Method

Fermentation is the natural process where beneficial bacteria, known as cultures, consume the lactose (milk sugar) and convert it into lactic acid. For commercially produced yogurts, this process is often short, leaving a significant amount of lactose behind. By extending the fermentation time, you can give the cultures more opportunity to break down the lactose, resulting in a virtually lactose-free product.

Supplies for 24-Hour Fermentation

• 1/2 gallon (2 quarts) of whole milk (avoid ultra-pasteurized, as it can affect texture)
• 1/4 cup of high-quality plain yogurt with live, active cultures
• Yogurt maker or Instant Pot with yogurt function
• Thermometer
• Sterilized glass jars with lids

Step-by-Step Process

1. Heat the milk: Pour the milk into a saucepan and heat it to 180°F (82°C) while stirring occasionally to prevent scorching. This denatures the milk proteins, resulting in a thicker yogurt.
2. Cool the milk: Remove the milk from the heat and allow it to cool down to 105-115°F (40-46°C). This is the ideal temperature for the starter cultures to thrive without being killed.
3. Add the starter culture: In a separate bowl, whisk the starter yogurt with a small amount of the cooled milk until smooth. Pour this mixture back into the main pot of milk and whisk thoroughly to combine.
4. Incubate for 24 hours: Pour the inoculated milk into sterilized jars or the Instant Pot liner. Incubate for a full 24 hours, maintaining a consistent temperature. A yogurt maker or Instant Pot automates this perfectly.
5. Chill the yogurt: Once fermentation is complete, move the yogurt directly to the refrigerator. Chilling for at least 6 hours helps it set further and enhances the flavor. Do not stir it until it is fully chilled.

Straining Yogurt to Remove Lactose

Another highly effective method is straining. Lactose is a water-soluble carbohydrate, so it resides in the liquid whey that separates from the milk solids. By straining the yogurt, you remove a significant portion of this whey, concentrating the yogurt and reducing its lactose content. This is how Greek yogurt and even thicker labneh are made.

Tools for Straining

• A large bowl
• A fine-mesh sieve or colander
• Cheesecloth, a nut milk bag, or coffee filters
• Plain yogurt (homemade or store-bought with live cultures)

Straining Instructions

1. Prepare the setup: Place the sieve over the large bowl, ensuring there is plenty of space for the whey to collect. Line the sieve with several layers of cheesecloth or a nut milk bag.
2. Add the yogurt: Spoon your plain yogurt into the lined sieve. Cover the top with plastic wrap to prevent the yogurt from absorbing any refrigerator smells.
3. Refrigerate and wait: Place the entire setup in the refrigerator. For Greek-style yogurt, strain for 8-12 hours. For an even thicker, cream cheese-like consistency (labneh), strain for 24-48 hours.
4. Enjoy: The longer you strain, the thicker the yogurt becomes and the more lactose is removed. Transfer the thickened yogurt to an airtight container. The collected whey can be used for other recipes, like baking.

Comparison of Lactose-Reduction Methods

Feature	Extended Fermentation	Straining	Store-Bought Lactose-Free Yogurt
Principle	Beneficial bacteria consume lactose over a longer period.	Whey, containing lactose, is physically removed.	Lactase enzyme is added during processing.
Final Texture	Rich and creamy, similar to traditional yogurt.	Thick and concentrated, like Greek yogurt or labneh.	Varies by brand, but generally creamy.
Flavor Profile	Tangier due to higher lactic acid content.	Tangier and more concentrated due to whey removal.	Often tastes slightly sweeter than regular yogurt due to enzyme action.
Process Time	24+ hours of fermentation.	8-48 hours of refrigeration.	No at-home process required.
Equipment Needed	Yogurt maker, thermometer, jars.	Sieve, cheesecloth, bowl.	None, just a store visit.
Cost	Less expensive in the long run.	Minimal cost for straining tools.	Can be more expensive than regular yogurt.

Can I Use Both Methods for a Super Low-Lactose Yogurt?

Yes, absolutely. For the lowest possible lactose content, you can start by performing an extended, 24-hour fermentation. Once the fermentation is complete and the yogurt has been chilled, proceed with the straining method. This two-step process ensures the maximum amount of lactose has been broken down and then physically removed. The result is an exceptionally thick, tangy, and highly digestible yogurt. This is the preferred method for individuals with severe lactose intolerance, like those following the Specific Carbohydrate Diet (SCD).

Conclusion

Whether you opt for a longer fermentation time or the simple straining method, you can effectively reduce the lactose content in yogurt at home. For those with a mild sensitivity, store-bought lactose-free yogurt is a convenient choice, but for maximum control and digestive comfort, making it yourself is the best approach. By extending the fermentation process, live cultures consume more of the lactose, while straining removes the whey where lactose resides. Combining both methods offers the highest degree of lactose reduction, allowing even those with significant intolerance to enjoy the nutritional benefits of dairy yogurt.

Authoritative Source

• Luvele US: https://www.luvele.com/blogs/recipe-blog/how-to-strain-homemade-yogurt

Frequently Asked Questions

Does fermentation really remove all the lactose from yogurt?

Extended fermentation for 24 hours significantly reduces lactose, but it may not remove all of it. The longer fermentation time allows the live cultures to consume most of the lactose, but trace amounts may remain.

Can I use store-bought yogurt to make more low-lactose yogurt?

Yes, you can use a high-quality, plain yogurt with live active cultures as a starter for your next batch. This method of using a starter is common in homemade yogurt production.

What is the difference between lactose-free and dairy-free yogurt?

Lactose-free yogurt is a dairy product where the lactose has been broken down using an enzyme. Dairy-free yogurt contains no dairy at all and is made from plant-based sources like soy, coconut, or almond milk.

How do I know if my yogurt has successfully fermented for 24 hours?

A 24-hour fermented yogurt will be noticeably tangier and slightly thicker than a standard fermented one. The final texture also depends on the fat content of the milk used.

What are some practical uses for the leftover whey?

Whey is great for baking, as it can be used to replace water in bread, pancakes, and other recipes. It can also be added to smoothies for extra protein or used as a starter for other fermented products.

Does straining yogurt remove other nutrients besides lactose?

Straining primarily removes the whey, which contains the lactose. While some water-soluble vitamins might be lost, the yogurt becomes more concentrated in protein and fat, which are in the milk solids.

Can I use lactose-free milk to make low-lactose yogurt?

Yes, you can use store-bought lactose-free milk to make yogurt. This will result in a yogurt that is already low in lactose from the start, which can then be fermented and strained for an even lower lactose content if desired.