Kombucha - What are the Characteristics of the Fermented Tea Beverage

Kombucha hails from China, where it is considered a purifying and invigorating beverage. It is a microbiological tea culture with a jelly-like consistency, which is produced through the fermentation of tea using SCOBY (a symbiotic culture of bacteria and yeasts). The beverage is created by fermenting mostly black or green tea with added sugar, making use of SCOBY microorganisms, which can differ depending on the climatic, geographical conditions and local availability of specific species of bacteria and yeast. The fermentation process typically takes around 10-12 days. Following this period, a sour, slightly carbonated and fruity beverage containing numerous bioactive compounds is formed.

Kombucha contains the following bioactive substances: organic acids, sugars, vitamins, minerals, amino acids and proteins, lipids, ethanol, and polyphenols. Kombucha contains acetic acid and catechins, which give it antibacterial and antifungal properties. It also inhibits the growth of unwanted bacteria that are Gram-positive (+) and Gram-negative (-). Studies have shown that kombucha made from green tea has a stronger antibacterial effect than kombucha made from black tea. The low pH of kombucha prevents contamination by unwanted yeasts, bacteria, and fungi. It is important to note that most studies on kombucha have been conducted on animal models or in vitro.

Individuals who consume kombucha often report experiencing headaches, dizziness, nausea, vomiting, and allergic reactions. Moreover, cases of lactic acid and acute renal failure 15 hours after drinking tea have been described (R. Jayabalan et al., 2014, S. A. Kole et al. 2009). These are usually isolated cases affecting a small number of individuals, but it is important to note that kombucha consumption can cause unpleasant side effects. When preparing kombucha at home, caution is advised – contamination of the product and the presence of pathogenic bacteria, such as Bacillus, is possible. It is recommended to use suitable containers (without cracks, intended for food contact) for the preparation of kombucha. Due to the alcohol content that arises from the acetic fermentation of the tea, children, pregnant women, breastfeeding mothers, and individuals with advanced kidney and lung diseases should not consume kombucha. Kombucha contains high levels of histamine, therefore it is also not recommended for individuals with histamine intolerance. Kombucha contains sugar, hence the information on consumption for diabetics and individuals with diagnosed insulin resistance is inconsistent.

Required components: dried tea leaves - around 6 g, sucrose or honey - about 100 g, water - 1 litre, SCOBY starter culture - 24 g. Method: Position the ingredients in a pot and boil them for a minimum of 5 minutes. Filter the infusion and move it into a glass vessel. Cool the infusion to room temperature, approximately 20-30°C. Include the SCOBY starter culture. Let the beverage ferment for 10-12 days at a temperature between 18-26°C (best covered with a glass lid). After this period, extract the mushroom, stir the beverage and filter it. Keep the finished Kombucha in a cool place, like the refrigerator, at a temperature of about 4-5°C. Maintaining a high level of hygiene is crucial to avoid contamination of the drink by the microflora on your hands. Thoroughly wash your hands after every pause in Kombucha preparation. You can utilize different types of sugar, such as cane sugar or coconut sugar. Incorporate ginger, lemon or your preferred fruit to the finished beverage. The lifespan of the mushroom is roughly 2 years, but you can replace it more frequently. A mushroom offspring is generated at each fermentation process of a new Kombucha, which can be employed in a subsequent process. Kombucha is a revitalizing beverage with antioxidant properties that is produced by the involvement of fermenting bacteria that have a beneficial effect. The American Food and Drug Administration (FDA) stated that human consumption of Kombucha is safe. Nevertheless, the majority of research on the benefits and health-promoting effects of this beverage has been conducted in vitro and on animals. Scientific evidence of its effects on humans is still deficient.