Kombucha is one of the most intensively studied fermented beverages in recent years. Modern microbiological, nutritional, and clinical studies show that the beverage has an exceptionally complex biochemical composition. During fermentation, numerous bioactive compounds are formed, including organic acids, polyphenols, enzymes, vitamins, and various microorganisms.
Current scientific literature investigates various properties of Kombucha and its fermentation. The focus includes its microbiological composition, organic acids, polyphenols, and possible changes in various parameters studied. However, the results differ depending on the recipe, manufacturing process, and study design. Kombucha is therefore primarily a scientifically interesting fermented tea beverage 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, where 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 like 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 investigations, various phenolic compounds have been detected in different Kombucha samples. Which compounds are actually present and in what concentration depends, among other factors, on the tea, culture, and manufacturing process.
Polyphenols and other ingredients are studied 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 beverage's antioxidant effect in the human body.
A review investigated 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 beverage 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 studied in scientific research in connection with the gut microbiome.
Influence on the gut microbiome
The gut microbiome is one of the central research topics in modern nutritional science. Fermented foods are a particular 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 differ depending on the study, the product examined, and the population group.
An intervention study with regular Kombucha consumption showed changes in 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 intestinal lining cells.
The study also investigated changes in the Bifidobacterium population.
Research on digestion and gut function
Several clinical studies focus on 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 examined, 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 studied 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 its composition, quantity, and the current research situation.
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 the effects of daily Kombucha consumption over six weeks. Both metabolic parameters and changes in the gut microbiome were analyzed.
The results showed:
- Changes in lipid metabolism
- A reduction in triglyceride levels
- Changes in the gut microbiota in favor of certain bacterial groups
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 studied, 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 of certain Kombucha samples is also investigated under laboratory conditions.
These are primarily caused by several factors:
- Acetic acid
- Gluconic acid
- Low pH value
- Phenolic compounds
In laboratory studies, antimicrobial activity was 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 beverage (Bauer & Petrusevska-Tozi, 2001).
These include:
- 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, which 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 address the microbial diversity, plant compounds, and metabolites formed during the fermentation of Kombucha (Batista et al., 2023).
The following areas are discussed, among others:
- Metabolic processes
- Oxidative stress
- Gut microbiome
- General well-being
Even popular science summaries of the research highlight that Kombucha contains a variety of bioactive ingredients formed through fermentation (Leech, 2023; Herzig, 2025).
Conclusion: Kombucha – a versatile fermented beverage in the spotlight 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 manufacturing process.
Especially the microbiological composition and the metabolites 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 so far come from different study models, recipes, manufacturing processes, and population groups. Therefore, they do not allow for a general statement about a health benefit of Kombucha or the effect of a specific Kombucha product.
Kombucha is thus primarily a scientifically interesting fermented tea beverage whose complex composition and fermentation processes continue to be subjects of research.
Study overview
Kombucha: Refreshing and healing through fermentation
Herzig, K. (2025). Kombucha: Refreshing and healing through fermentation. G. Dorschner (Examiner). You can find the complete article here.
7 Evidence-Based Health Benefits of Kombucha
Leech, J. (2023). 7 Evidence-Based Health Benefits of Kombucha. Healthline. You can find the complete article here.
The health benefits of the nutritional compounds and metabolites of Kombucha
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.
A review on Kombucha tea—Microbiology, composition, fermentation, beneficial effects, toxicity, and tea fungus
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 markers
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.
The effect of Kombucha on physical and mental health
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.
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