Do Fermented Drinks Have Less Sugar?

December 30, 2025 •

3 min read

Fermentation is an ancient process that has been used for centuries to preserve food and enhance flavor. During this process, microorganisms like yeast and bacteria consume sugars, converting them into other compounds. As a result, the final sugar content of a fermented drink is often significantly lower than the original ingredients, making it an appealing choice for those monitoring their intake.

Quick Summary

Fermentation utilizes sugar as a food source for microbes, resulting in a lower sugar content in the final drink. The amount of sugar reduction depends on the fermentation time and specific process. This makes many fermented beverages a lower-sugar alternative to sugary sodas and juices.

Key Points

Microbes consume sugar: The fermentation process relies on bacteria and yeast to consume sugar, leading to a reduced sugar content in the final drink.
Longer fermentation, less sugar: The duration of fermentation is a key factor; the longer the microbes ferment, the more sugar they convert, resulting in a less sweet product.
Check for added sugars: Many commercial brands add extra fruit juice or sugar after fermentation, so it's vital to check the nutritional label for the final sugar count.
Fermented vs. sugary drinks: Fermented options like kombucha and kefir are significantly lower in sugar than sugary sodas or juices.
Probiotics aid metabolism: The probiotics in fermented drinks may help support a healthy gut microbiome, which can assist in regulating blood sugar.
Plain is best: For the lowest sugar content, opt for plain, unflavored, or homemade versions of fermented drinks, which have no added sweeteners after fermentation.

Understanding the Fermentation Process

Fermentation is a metabolic process where microorganisms, such as yeast and bacteria, convert carbohydrates like sugar into alcohol or organic acids under anaerobic conditions. For fermented drinks, this essentially means the microbes 'eat' the sugar, leaving behind a lower-sugar product. The specific outcome depends on the type of fermentation (e.g., lactic acid or alcohol), the microbial cultures used, and the duration of the fermentation itself.

How Sugar Reduction Varies

The sugar content of a fermented drink is not a static number; it's a dynamic variable influenced by several factors:

Duration of Fermentation: The longer the fermentation period, the more time the microbes have to consume the sugars. For example, a kombucha fermented for three weeks will have significantly less sugar than one fermented for just one week. This is why homebrewers can customize the sweetness of their drinks by simply extending or shortening the fermentation time.
Initial Sugar Content: The amount of sugar in the starting ingredients (e.g., the sweet tea for kombucha or milk for kefir) directly impacts the final sugar level. While fermentation reduces sugar, a drink that starts with a high sugar concentration will likely still end up with more residual sugar than one that started with less.
Microbial Culture: Different microbial cultures consume sugar at different rates and produce different end products. The SCOBY in kombucha, for instance, operates differently than the kefir grains used to ferment milk.
Post-Fermentation Flavoring: Many commercial fermented drinks add extra fruit juice or other flavorings after the initial fermentation. This adds sugar back into the product, so it's crucial to read the nutritional label to understand the total sugar content.

Comparison of Fermented Drinks vs. Non-Fermented Counterparts

Fermented Drinks vs. Sugary Sodas and Juices

Compared to conventional sugary beverages like soda and fruit juice, the sugar difference is dramatic. While a 12-ounce can of soda contains approximately 39 grams of sugar, an 8-ounce serving of unflavored kombucha often contains just 2–6 grams. This stark contrast makes fermented options a compelling choice for those looking to curb sugar intake.

Yogurt vs. Milk

Plain yogurt is a fermented milk product. During its creation, bacteria ferment the lactose (milk sugar). This process reduces the overall sugar content; plain yogurt can have about 23% less sugar than the milk it was made from. However, be wary of flavored yogurts, which often have high amounts of added sugar.

Table: Sugar Content Comparison


Beverage Type	Example	Typical Sugar Content (per serving)	Key Takeaway
Fermented	Plain Kefir (1 cup)	~7 grams	Significantly lower sugar than milk and soda.
Fermented	Unflavored Kombucha (8 oz)	2–6 grams	Very low in sugar, especially homemade versions.
Non-Fermented	2% Milk (1 cup)	~12 grams	The unfermented version of kefir contains more sugar.
Non-Fermented	Soda (12 oz)	~39 grams	Contains exceptionally high levels of added sugar.
Non-Fermented	Apple Juice (8 oz)	~25 grams	Natural fruit juices can still be high in sugar.

The Role of Probiotics and Gut Health

The reduced sugar in fermented drinks is a major benefit, but it's not the only one. The fermentation process also creates beneficial probiotics and organic acids. A healthy gut microbiome, supported by probiotics, has been linked to better blood sugar regulation. By opting for low-sugar fermented drinks, you are not only reducing your overall sugar consumption but also potentially supporting your gut health and metabolic balance.

Making Healthier Choices

To get the most benefit, it is advisable to choose unflavored, raw, or homemade versions of fermented drinks. Always read the label of store-bought products to check for added sugars, as some brands sweeten their products after fermentation. Many people find the naturally tangy, less sweet flavor of these beverages becomes an acquired taste, offering a healthier and more complex alternative to syrupy-sweet sodas and juices.

Conclusion

Fermented drinks generally do have less sugar than their unfermented or commercially sweetened counterparts because the microorganisms responsible for fermentation consume a significant portion of the sugar. This makes them a preferable choice for individuals seeking to reduce their sugar intake. However, it is essential to be a discerning consumer by reading labels and opting for products with minimal or no added sugars post-fermentation. By doing so, you can enjoy the benefits of a lower-sugar beverage while also nourishing your gut with beneficial probiotics.

Fermentation is a time-tested method for reducing sugar content, improving digestion, and creating nutrient-dense foods.

Frequently Asked Questions

Fermented drinks have less sugar because the microorganisms used in the fermentation process, such as bacteria and yeast, consume the sugar as their food source. They convert these sugars into other compounds like organic acids and carbon dioxide, leaving behind a drink with a lower sugar content than its unfermented base.

No, not all kombucha is low in sugar. While the initial fermentation process does reduce sugar, many commercial brands add additional fruit juice or sweeteners after fermentation to enhance flavor. To ensure you're getting a low-sugar option, always check the nutrition label and look for unflavored varieties.

Yes, plain kefir generally has less sugar than milk. The kefir grains ferment the lactose (milk sugar) during production, converting a portion of it into lactic acid. For example, one cup of plain kefir contains approximately 7 grams of sugar, while an equivalent amount of 2% milk contains about 12 grams.

To determine if a fermented drink has added sugar, read the ingredients list on the product label. Look for ingredients like fruit juice concentrates, cane sugar, or other sweeteners listed in addition to the base ingredients. Some brands will also explicitly label their products as having no added sugar or low sugar.

Yes, sugar is a necessary ingredient for fermentation as it is the fuel source for the microbes. For kombucha, it is added to sweet tea, and for milk kefir, lactose is the natural sugar source. However, the microbes consume this sugar, so the final product will be much lower in sugar than what you started with.

Lower-sugar, unflavored fermented drinks can be a better option than high-sugar sodas and juices for people with diabetes. The probiotics they contain may also support blood sugar regulation. However, it is always recommended to consult with a doctor or registered dietitian before making significant changes to your diet.

The lowest sugar fermented drinks are typically unsweetened, raw, or homemade versions that have undergone a longer fermentation period. Drinks like water kefir or kombucha made without added fruit juices or sweeteners after fermentation are good examples. You can also find some commercial brands that market themselves specifically as low or no-sugar.