Kombucha is one of the most intensively studied fermented beverages of recent years. Modern microbiological, nutritional, and clinical studies show that the drink possesses an exceptionally complex biochemical composition. Numerous bioactive compounds are formed during fermentation, including organic acids, polyphenols, enzymes, vitamins, and various microorganisms.
Current scientific literature investigates various properties of Kombucha and its fermentation. The focus includes, among other things, its microbiological composition, organic acids, polyphenols, and possible changes in various parameters studied. However, the results differ depending on the recipe, production method, and study design. Kombucha is therefore primarily a scientifically interesting fermented tea drink with a complex composition.
Fermentation: The basis of its biochemical composition
Kombucha is produced by fermenting sweetened tea with a so-called SCOBY culture (Symbiotic Culture of Bacteria and Yeast). This symbiotic community of bacteria and yeasts forms a variety of bioactive metabolites during fermentation.
A comprehensive review describes Kombucha as a dynamic microbial ecosystem in which yeasts convert sugar into ethanol and carbon dioxide, while acetic acid bacteria further metabolize this alcohol into organic acids (Jayabalan et al., 2014).
Key substances formed during fermentation include:
- Acetic acid
- Gluconic acid
- Glucuronic acid
- Lactic acid
- Polyphenol metabolites
- Bacterial enzymes
This biochemical transformation results in Kombucha having a significantly different composition than the original tea.
Recent microbiological analyses show that more than 200 different microbial species from over 30 genera can be identified in Kombucha (Nutritional Metagenomics Analysis, 2021). Particularly dominant are acetic acid bacteria such as Acetobacter and Komagataeibacter, which are responsible for the production of organic acids.
Polyphenols from tea and fermentation
One area of research concerning Kombucha involves polyphenols and other compounds studied for their antioxidant properties. Tea naturally contains various polyphenols, including catechins, flavonoids, and phenolic acids. During fermentation, their composition can change.
In scientific studies, various phenolic compounds have been detected in different Kombucha samples. Which compounds are actually present and in what concentration depends, among other things, on the tea, culture, and manufacturing process.
Polyphenols and other ingredients are investigated in laboratory and nutritional studies in connection with oxidative processes and various metabolic parameters. However, their presence in Kombucha does not allow for a general conclusion about the drink's antioxidant effect in the human body.
A review examined which phenolic and other compounds were described in different Kombucha samples and how their composition can change during fermentation (Martínez Leal et al., 2018).
The microbiological diversity of Kombucha
The microbiological composition of Kombucha is one of the most important factors for its properties.
A genetic analysis of several Kombucha samples showed that the drink contains a stable community of bacteria and yeasts (Marsh et al., 2014). The most common microorganisms include:
Bacteria
- Komagataeibacter
- Acetobacter
- Gluconobacter
- Lactobacillus
Yeasts
- Saccharomyces
- Brettanomyces
- Zygosaccharomyces
- Pichia
These microorganisms form complex metabolic networks during fermentation and produce numerous bioactive metabolites.
Microbiological diversity is considered one of the reasons why Kombucha is frequently investigated in scientific studies in connection with the gut microbiome.
Impact on the gut microbiome
The gut microbiome is one of the central research topics in modern nutritional science. Fermented foods are particularly in focus.
A controlled clinical study from 2024 investigated the effects of Kombucha consumption on the gut microbiome of adults. The analysis was based on high-resolution shotgun sequencing of stool samples (Ecklu-Mensah et al., 2024).
The results showed:
- Changes in the composition of the gut microbiota
- An increased presence of certain microbial species from fermented foods
- Adjustments in microbial metabolic pathways
Among other things, an increased relative abundance of Weizmannia coagulans and changes in metabolic pathways for vitamin and nucleotide biosynthesis were observed.
Further studies also investigated changes in the gut microbiome in connection with Kombucha consumption. The observed changes varied depending on the study, the product investigated, and the group of people.
An intervention study with regular Kombucha consumption showed changes in the gut flora, including:
- An increase in Bacteroidota
- An increased presence of Akkermansiaceae
- An increase in Subdoligranulum, a known butyrate-producing gut bacterium (Costa et al., 2025).
Butyrate is one of the most important short-chain fatty acids in the gut and serves, among other things, as an energy source for cells of the intestinal mucosa.
The study also examined changes in the Bifidobacterium population, among other things.
Research on digestion and gut function
Several clinical investigations deal with possible connections between Kombucha consumption and parameters of digestive function.
In individual studies, changes in gastrointestinal symptoms were also observed. How reliable such results are and whether they can be transferred to other Kombucha recipes or population groups depends on the respective study design, the product investigated, and other factors.
Microorganisms, organic acids, and other fermentation products are discussed as possible explanations. However, no general effect of Kombucha on digestive complaints can be derived from this.
Organic acids such as acetic acid, citric acid, or malic acid are among the substances that are investigated in connection with physiological processes in the gut. The significance of individual acids and whether effects can be derived from the consumption of a specific Kombucha depend on the composition, quantity, and current state of research.
Research on metabolism and metabolic parameters
Another area of research investigates Kombucha in connection with various metabolic parameters.
A randomized intervention study with 60 participants investigated daily Kombucha consumption over six weeks and analyzed various metabolic parameters and changes in the gut microbiome.
Under the conditions studied, changes in lipid metabolism, triglyceride levels, and the composition of the gut microbiota were observed. Whether and to what extent these results can be transferred to other Kombucha recipes, population groups, or the general consumption of Kombucha cannot be derived from this.
A systematic review summarized studies in which Kombucha was investigated in connection with various metabolic parameters, markers of oxidative stress, and changes in the gut microbiota. The results depend on the study design, the Kombucha investigated, and other factors and do not allow for a general health-related statement about Kombucha as a food.
Antimicrobial activity in laboratory studies
In addition to the microbial effects on the gut microbiome, antimicrobial activity in certain Kombucha samples is also investigated under laboratory conditions.
These are mainly caused by several factors:
- Acetic acid
- Gluconic acid
- Low pH
- Phenolic compounds
In laboratory studies, antimicrobial activity has been investigated in individual Kombucha samples. Acidity, organic acids, and plant compounds play a role in this. These properties are often attributed to the combination of organic acids and phenolic plant compounds.
Vitamins and minerals
In addition to fermentation-related metabolites, Kombucha also contains various micronutrients.
An analysis of the nutrient content showed the presence of several water-soluble vitamins and minerals in the drink (Bauer & Petrusevska-Tozi, 2001).
These include, among others:
- B vitamins
- Vitamin C
- Potassium
- Magnesium
- Iron
These micronutrients partly originate from the tea and are partly formed during fermentation.
Kombucha as a complex fermented food
Modern scientific reviews address Kombucha as a complex fermented food, whose composition is shaped by the interplay of tea, microorganisms, and fermentation conditions:
- Fermentation of tea
- Microbial ecosystem of bacteria and yeasts
- Formation of organic acids
- High concentration of plant polyphenols
- Production of microbial metabolites
This combination leads to an exceptionally complex biochemical structure that is increasingly being investigated in nutritional science.
A current review deals with the microbial diversity, the metabolites formed during fermentation, and various properties of Kombucha investigated in studies (Prajapati et al., 2024).
Kombucha in the context of current research
In addition to its biochemical properties, researchers are also investigating the role of Kombucha in the context of holistic nutrition.
Current scientific analyses intensively examine the microbial diversity, plant compounds, and metabolic products of Kombucha formed during fermentation (Batista et al., 2023).
Among other things, the following areas are discussed:
- Metabolic processes
- Oxidative stress
- Gut microbiome
- General well-being
Popular science summaries of the research also highlight that Kombucha contains a variety of bioactive ingredients created through fermentation (Leech, 2023; Herzig, 2025).
Conclusion: Kombucha – a versatile fermented beverage in the focus of research
Scientific research shows that Kombucha can have a complex composition. During the fermentation of tea, various microorganisms, organic acids, polyphenols, and other fermentation products can be present. Which substances are actually contained and in what quantities depends on the recipe, culture, and production method.
Especially the microbiological composition and the metabolic products formed during fermentation are subjects of current research. Possible connections with the gut microbiome, various metabolic parameters, and digestive processes are being investigated, among other things.
The results obtained so far come from different study models, recipes, production methods, and population groups. Therefore, they do not allow for a general statement about the health benefits of Kombucha or the effect of a specific Kombucha product.
Kombucha is thus primarily a scientifically interesting fermented tea drink whose complex composition and fermentation processes remain subjects of research.
Study overview
Kombucha: Refreshing and Healing through Fermentation
Herzig, K. (2025). Kombucha: Refreshing and Healing through Fermentation. G. Dorschner (rev.). You can find the complete article here.
7 Research Areas Where Kombucha Is Scientifically InvestigatedLeech, J. (2023). 7 Evidence-Based Health Benefits of Kombucha. Healthline. You can find the complete article here.
Ingredients and Metabolites of Kombucha in Research
Martinez Leala, J., Valenzuela Suárez, L., Jayabalan, R., Huerta Oros, J., & Escalante-Aburto, A. (2018). A review on health benefits of kombucha nutritional compounds and metabolites. CyTA - Journal of Food, 16(1), 390-399. You can find the complete article here.
Minerals and Vitamins in Kombucha
Bauer, B., & Petrusevska Tozi, L. (2001). Mineral and water soluble vitamin content in the Kombucha drink. International Journal of Food Science & Technology, 35(2), 201-205. You can find the complete article here.
An Overview of Kombucha – Microbiology, Composition, Fermentation & Health Benefits
Jayabalan, R., Malba, R. V., Lonar, E. S., Vitas, J. S., & Sathishkumar, M. (2014). A review on Kombucha tea—Microbiology, composition, fermentation, beneficial effects, toxicity, and tea fungus. Comprehensive Reviews in Food Science and Food Safety, 13(4), 538-550. You can find the complete article here.
Impact of Kombucha on the Human Gut Microbiome and Key Health Indicators
Ecklu-Mensah, G., Miller, R., Maseng, M. G., Hawes, V., Hinz, D., Kim, C., & Gilbert, J. A. (2024). Modulating the human gut microbiome and health markers through kombucha consumption: A controlled clinical study. Scientific Reports, 14(1), 31647. You can find the complete article here.
Microbiological Study on Kombucha Alchemy: Analysis of Bacterial Compositions
Marsh, A. J., O'Sullivan, O., Hill, C., Ross, R. P., & Cotter, P. D. (2014). Sequence-based analysis of the bacterial and fungal compositions of multiple kombucha (tea fungus) samples. Food Microbiology, 38, 171-178. You can find the complete article here.
What Studies on Kombucha are Currently Investigating
Batista, P., Rodrigues Penas, M., Vila-Real, C., Pintado, M., & Oliveira-Silva, P. (2023). Kombucha: Challenges for health and mental health. Foods (Basel, Switzerland), 12(18), 3378. You can find the complete article here.
Share: