Does Kombucha Have Living Bacteria in It? A Deep Dive into the Brew

December 21, 2025 •

4 min read

Kombucha is a fermented tea that has surged in popularity, celebrated for its unique tangy flavor and purported health benefits. At the heart of its creation lies a unique microbial community known as a SCOBY, which is the direct source of the living bacteria present in the final beverage. However, not all store-bought kombucha contains live bacteria, making it essential for consumers to understand the production process.

Quick Summary

Kombucha is made using a symbiotic culture of bacteria and yeast (SCOBY) which ferments sweetened tea, producing live bacteria, or probiotics. The presence of these live cultures depends on whether the final product is raw and unpasteurized or has undergone a heat-treatment process that eliminates the microbes.

Key Points

Source of Live Bacteria: The fermentation process, driven by a symbiotic culture of bacteria and yeast (SCOBY), is what introduces living bacteria, or probiotics, into kombucha.
Read the Label: The only way to guarantee live bacteria is to select raw, unpasteurized kombucha, which is typically labeled as such.
Pasteurization Kills Probiotics: Heat-treated or pasteurized kombucha is shelf-stable but lacks the naturally occurring live microbes because the heat process kills them.
Supports Gut Health: The probiotics in live kombucha contribute to a diverse and healthy gut microbiome, which can aid digestion and support the immune system.
Check for Refrigeration: Real, live kombucha must be kept refrigerated to slow down fermentation; if it's found on a store's room-temperature shelf, it has been pasteurized.
Safety Considerations: While generally safe, individuals who are pregnant, breastfeeding, or immunocompromised should consult a doctor and may prefer pasteurized kombucha due to the small risk of bacterial contamination.
Visual Indicators: The presence of sediment or visible strands in kombucha is a sign of live cultures and is a normal part of the fermentation process.

The Science Behind Kombucha: How Live Bacteria Are Made

At its core, kombucha's essence comes from a biological process called fermentation. This is orchestrated by a symbiotic culture of bacteria and yeast, or SCOBY, which is a key ingredient for brewing. The SCOBY is a gelatinous, cellulose-based matrix that serves as a home for a complex ecosystem of microorganisms.

Here’s a breakdown of the fermentation process:

Yeast Action: The yeast in the SCOBY first consumes the sugar added to the tea.
Alcohol and CO2 Production: As it feeds on the sugar, the yeast produces ethanol (a small amount of alcohol) and carbon dioxide, which gives kombucha its characteristic fizz.
Bacteria Action: The bacteria, primarily acetic acid bacteria, then feed on the ethanol and convert it into various organic acids, such as acetic acid and gluconic acid. This conversion is what gives kombucha its distinct tangy or vinegary flavor.

This continuous process is what fills the beverage with a vibrant population of live microbes, or probiotics. These beneficial bacteria are considered one of the main drawcards for kombucha's health appeal.

Raw vs. Pasteurized Kombucha: Not All Are Alike

For consumers, the most important factor in determining if kombucha contains live bacteria is whether it is raw and unpasteurized or has been heat-treated. This distinction significantly impacts the beverage's probiotic content.

Raw and Unpasteurized Kombucha: This is kombucha in its most natural, unprocessed form. It has not been subjected to heat and therefore retains all the live and active bacterial and yeast cultures created during fermentation. You can often tell if a kombucha is raw if it requires refrigeration and has sediment or small, floating strands of SCOBY. The fermentation process continues slowly in the fridge, giving it a shorter shelf life than its pasteurized counterparts.
Pasteurized Kombucha: To increase shelf life and ensure a stable product with a consistent flavor and alcohol level, some manufacturers choose to pasteurize their kombucha. This heat-treatment process kills all the living bacteria and yeasts, including the beneficial probiotics. While it eliminates any risk of harmful bacterial contamination, pasteurized kombucha loses the gut health benefits associated with live cultures. Some brands may add shelf-stable probiotics after pasteurization, but this is a different profile than the diverse, naturally-occurring bacteria in raw kombucha.

Identifying Live Kombucha: A Consumer’s Guide

Since not all kombucha has living bacteria, savvy shoppers should learn how to identify the raw product. Here are some simple indicators:

Check the Label: Look for terms like "raw," "unpasteurized," "live and active cultures," or "contains probiotics". If the label mentions pasteurization or doesn't mention live cultures, it likely lacks the beneficial bacteria.
Location in the Store: Unpasteurized kombucha must be kept refrigerated to slow fermentation. If you find it on a shelf at room temperature, it has most likely been pasteurized.
Appearance: Raw kombucha often has a cloudy appearance, and you may see strands or sediment at the bottom of the bottle. This is a normal sign of the live cultures and is perfectly safe to consume. A perfectly clear liquid is often a sign of pasteurization.

The Role of Live Bacteria in Health

The live bacteria and yeast found in kombucha are what classify it as a probiotic-rich food, much like yogurt or kefir. While the scientific community is still conducting research on the full extent of kombucha's health benefits in humans, probiotics are generally known to support gut health.

Digestive Aid: Probiotics help to maintain a diverse and balanced gut microbiome, which is crucial for proper digestion and nutrient absorption. This can help with issues like bloating and constipation.
Immune System Support: A healthy gut is linked to a strong immune system, and the probiotics in kombucha may help fortify the body's natural defenses.
Antioxidants: The fermentation process and the tea base provide antioxidants, which help protect the body's cells from damage caused by free radicals.

Comparison of Raw vs. Pasteurized Kombucha


Feature	Raw (Unpasteurized) Kombucha	Pasteurized Kombucha
Live Cultures	Abundant live bacteria and yeast (probiotics)	Live microbes eliminated by heat
Flavor Profile	Complex, richer, more dynamic, may vary slightly batch to batch	Milder, more consistent flavor profile
Shelf Life	Shorter shelf life (requires refrigeration)	Extended shelf life (shelf-stable)
Appearance	Often cloudy, with visible strands of sediment	Clear liquid, free of sediment
Safety	Generally safe from harmful pathogens due to low pH and beneficial microbes	Highest safety, but probiotic benefit is lost unless added post-process

Conclusion: Making an Informed Choice

Does kombucha have living bacteria in it? Yes, traditionally brewed kombucha does, but only if it is a raw, unpasteurized product. The entire foundation of kombucha's appeal as a probiotic beverage rests on this distinction. The presence of a Symbiotic Culture of Bacteria and Yeast (SCOBY) during fermentation produces a rich ecosystem of live cultures that can benefit gut health. When choosing a kombucha, always check the label for terms like "raw" or "live and active cultures" and ensure it is refrigerated. For those with compromised immune systems or who are pregnant, consulting a healthcare provider and opting for a pasteurized version is the safest approach. For most healthy individuals seeking the probiotic benefits, the raw, unpasteurized version is the intended choice.

For more information on the symbiotic relationship within a SCOBY, visit Cultures For Health.

Frequently Asked Questions

SCOBY stands for 'Symbiotic Culture Of Bacteria and Yeast'. It is a living culture, often appearing as a thick, gelatinous disc, that consumes sugar in sweetened tea to produce kombucha through fermentation.

Yes, the floating strands are perfectly safe to drink. They are remnants of the SCOBY and are a natural indicator that the kombucha is raw and contains live, active cultures.

Look for kombucha in the refrigerated section and check the label for terms like 'raw' or 'live and active cultures'. Pasteurised kombucha is often shelf-stable and does not mention live cultures.

No, not all store-bought kombucha contains live bacteria. The live cultures are killed if the kombucha is pasteurized for a longer shelf life, so you must choose a raw, unpasteurized product to get the probiotic benefits.

Pasteurized kombucha retains some nutrients from the tea, like antioxidants, but it loses the probiotic benefits because the heat-treatment kills the live cultures. Some brands add shelf-stable probiotics after pasteurization, but this is a different microbial profile.

Commercial kombucha manufacturers adhere to strict food safety guidelines. Homemade kombucha, while potentially containing beneficial microbes, carries a higher risk of contamination if proper sanitation is not followed.

Raw, unpasteurized kombucha must be refrigerated to slow down the fermentation process and maintain its quality and taste. Pasteurized versions are shelf-stable and can be stored at room temperature.

The amount of sugar in kombucha can vary widely depending on the brand and flavor. While sugar is necessary to feed the SCOBY during fermentation, much of it is consumed by the microbes. It is always wise to check the nutrition label.