How long does cheese age before lactose is free?

November 17, 2025 •

3 min read

Over 65% of the world's population has some degree of lactose intolerance, yet many can still enjoy cheese. This is because the cheesemaking process, including aging, significantly reduces or eliminates lactose, explaining how long cheese ages before lactose is free.

Quick Summary

The duration of cheese aging required for minimal lactose varies by cheese type and production method. Lactic acid bacteria consume lactose during fermentation and aging, with most lactose being removed with the whey. Hard, aged cheeses typically contain very low to negligible amounts of lactose.

Key Points

Lactic Acid Bacteria: During cheesemaking, bacteria consume lactose and convert it to lactic acid, a critical first step in reducing lactose content.
Whey Separation: The majority of lactose is washed away with the liquid whey during the cheesemaking process, especially for harder cheeses.
Aging Further Reduces Lactose: As cheese matures, any remaining trace lactose is broken down by bacteria, with longer aging periods resulting in lower lactose levels.
Hard Cheeses are Best: Aged, hard cheeses like Parmesan, aged cheddar, and Swiss are typically lowest in lactose and safest for many lactose-sensitive individuals.
Fresh Cheeses Retain Lactose: Softer, fresher cheeses such as ricotta and cottage cheese have much higher lactose content due to minimal aging and less whey removal.
Tolerance Varies: Not all aged cheese is completely lactose-free, and individual tolerance levels differ. Check labels and choose longer-aged varieties for the lowest content.

The Science Behind Lactose Reduction

Understanding how lactose diminishes in cheese requires a look at the cheesemaking process. Lactose, the natural sugar found in milk, is not fully present in the final cheese product for several key reasons.

Fermentation by Lactic Acid Bacteria (LAB): Early in the process, starter cultures of LAB are added to the milk. These bacteria consume the lactose and convert it into lactic acid. This process is crucial for developing the cheese's flavor and texture.
Whey Separation and Drainage: After fermentation, the milk curdles and separates into solids (curds) and liquid (whey). The majority of the lactose, being water-soluble, is contained within the whey. When cheesemakers drain off the whey, a significant amount of lactose is removed. The efficiency of this step is why hard cheeses, from which more whey is drained, end up with less residual lactose than soft cheeses.
Continued Aging: For aged cheeses, the remaining trace amounts of lactose continue to be consumed by the bacteria during the maturation period. For many hard cheeses, this process progresses until the lactose is virtually eliminated.

General Timelines for Low-Lactose Cheeses

While the goal isn't always complete lactose freedom, for most aged cheeses, the lactose content becomes so low it's not a concern for many people with lactose intolerance. There's no single timeline that applies to all cheese, as the specific aging period for near-lactose-free results varies by cheese type.

Swiss and Gruyère: Often reach virtually lactose-free levels after around 3 to 4 months of aging.
Aged Cheddar: Lactose levels become very low after about 12 months. Extra-mature varieties aged 18 months or more typically have negligible amounts.
Parmigiano-Reggiano: Requires a minimum of 12 months of aging, often more. The Parmigiano-Reggiano Consortium confirms it is naturally lactose-free due to its production and aging process.
Aged Gouda: Longer-aged Goudas (over one year) are much lower in lactose than younger versions. Extra-aged varieties are an excellent choice for those avoiding lactose.

The Spectrum of Lactose Content

Not all cheeses follow the same path to low-lactose status. Cheeses with shorter aging times or those where less whey is removed will retain more lactose.

Soft and Fresh Cheeses: Varieties like ricotta, cottage cheese, and cream cheese are produced quickly, and little whey is drained. As a result, they retain higher levels of lactose compared to their hard, aged counterparts.
Processed Cheeses: These can vary greatly in lactose content depending on the ingredients used. Always check the label, as fillers can sometimes impact lactose levels.
Washed-Curd Cheeses: For some cheeses, like Gouda, the curds are washed with water to remove additional lactose and control acidity. This method, combined with aging, helps reduce lactose significantly.

A Comparison of Cheeses by Lactose Content


Cheese Type	Aging Duration	Lactose Content (Approx.)	Suitability for Lactose Intolerance
Parmigiano-Reggiano	Min. 12 months	<0.01 g per serving	Excellent
Aged Cheddar	12+ months	<0.1 g per serving	Excellent
Swiss (Emmental)	Min. 3-4 months	<0.1 g per serving	Excellent
Aged Gouda	12+ months	<0.1 g per serving	Excellent
Feta	Min. 2 months	<0.1 g per 100g (sheep/goat)	Very Good
Brie	Short	0-1 g per 100g	Good (varies)
Fresh Mozzarella	Very short	1-3 g per 100g	Moderate
Ricotta	Fresh	High	Poor

Can you trust 'aged' cheese to be lactose-free?

While many aged cheeses have minimal lactose, it's not a universal guarantee. The length of aging and specific production methods are key. An extra-sharp, two-year-old cheddar will have far less lactose than a mild, three-month-old cheddar. Additionally, some individuals may have a higher sensitivity and could react to even trace amounts. Reading labels and understanding the specific cheesemaking process is always the best strategy for those with severe sensitivity. Some commercial brands also explicitly add the enzyme lactase to ensure their product is lactose-free.

Conclusion

The aging process is the primary mechanism by which lactose is removed from cheese, driven by the fermentation activity of lactic acid bacteria. For many varieties, this process, combined with whey drainage, leads to a product with negligible lactose, often within 3 to 12 months or more, making them safe for many with lactose intolerance. Hard, aged cheeses like Parmigiano-Reggiano, Swiss, and mature cheddar are the most reliable options. For those with higher sensitivity, checking labels for verified lactose-free products or choosing the longest-aged varieties is advisable. The journey from milk to a low-lactose cheese is a fascinating one, powered by microbial action that benefits flavor and digestibility.

You can learn more about cheesemaking and lactose reduction at this resource on how lactose disappears during the process.

Frequently Asked Questions

Yes, Parmigiano-Reggiano, with a minimum aging of 12 months, is virtually lactose-free due to its production and aging process. Most Parmesan varieties contain less than 0.01 grams of lactose per serving.

No, not all cheese becomes lactose-free. The extent of lactose reduction depends on the cheesemaking method and aging duration. Hard, aged cheeses are the most likely to become virtually lactose-free, while fresh, soft cheeses retain higher levels.

While generally higher in lactose than hard cheeses, some soft cheeses are relatively low. Mozzarella and Brie, for instance, contain less than 1 gram of lactose per 100g, but it is always best to check the nutritional information on the specific product.

The most reliable way is to check the nutritional label. Some labels, especially on specifically designated lactose-free products, will state that the sugar content (which in milk is lactose) is zero or very low. For many aged cheeses, checking the carbohydrate or sugar count is a good indicator.

The primary process is fermentation, where lactic acid bacteria convert lactose into lactic acid. The second key step is the draining of the whey, which removes most of the water-soluble lactose.

Many people with moderate lactose intolerance can enjoy aged cheeses without issue, as the lactose levels are minimal. However, individuals with severe intolerance or a very low tolerance threshold should consult with a healthcare professional before consumption, as individual sensitivities vary.

No, milk from goats and sheep also contains lactose. While some feta made from sheep or goat milk may be aged and lower in lactose, the milk itself is not inherently lactose-free. The aging and production process is the critical factor for lactose reduction, regardless of the animal milk used.