What is Kombucha ?

Kombucha looks like a fungus but the comparison stops there. The kombucha is a tough, slippery, waxy mass composed out of several layers. Those layers are made of a transparent, very tough tissue with a series of brown spots, mainly at the bottom. Looking through a microscope you can see that the brown spots are concentrations of yeast cells.

The smooth, white side of the fungus is the top side, the fungus grows upward from here. The bottom side is rough and brown. The fungus first grows in width, then in thickness and it takes the form of the receptacle in which it lies. A round demijohn gives a round fungus, a square receptacle a square fungus. The larger the recipient the larger the fungus.

The kombucha fungus can be a smooth, transparent, waxy round plate one time or a white/grey uneven mass the next. Sometimes it’s a leathery thick layer with scarred tissue or a convex slice with bubbles on top and slimy threads below, giving it a jellyfish appearance.

Fact is, kombucha is a variable community of all sorts of yeast and bacteria, a complex of tiny microscopically creatures, a factory that produces all sorts of useful and wholesome substances through complex biochemical reactions.

As a living creature the fungus is subordinate to external factors, such as nutrition and oxygen, temperature, etc. It can vary in composition depending on the influence of the applied cultivation, by its origin and hygiene.

The fungus doesn’t always react to its environment in the same way, so it won’t have the same appearance all the time, just like two apples from the same tree are never alike.


  • Fermentation receptacle:It’s best that the kombucha fungus doesn’t have longterm contact with metal, plastic or other synthetic material. Unwanted chemical reactions will occur and toxic metal salts are formed when using one of these receptacles. The safest, most trouble-free manner is to use a glass receptacle.
  • Clear water:The quality of the water plays a significant role in the preparation of kombucha. Soft, clear drinking water is an absolute necessity, free from chlorine and fluorine (added to the tap water in some countries). The most sufficient method would be the use of tap water combined with a water softener.
  • Tea:Only non-perfumed black or green tea is suitable, these contain essential nutrients the kombucha needs.
  • Sweetener: Sugars serve as the energy source for the kombucha.
  • Warmth:The right temperature is crucial, temperatures below 18 °C are harmful for the fermentation. The optimal temperature lies around 25 to 30 °C. With the use of a warming plate you can easily create a constant temperature for the fermentation process.
  • Oxygen:Oxygen is vital, never hermetically seal your demijohn. Close the jar with a fine meshed cloth that’s held in place by an elastic band. No dirt or vinegar flies are allowed near the fungus.
  • Hygiene:First of all: wash your hands thoroughly with non-perfumed soap. Keep the necessary equipment spotless. Always rinse with clear (boiling) water. Do not use disinfectants like bleach. Keep your workplace clean and free of unnecessary objects. Remove flower pots from the area as the germs can cause infection.
  • Rest: The growth of a new fungus begins with a thin film at the surface of the liquid. This film won’t grow if the surface is disturbed. Later, when the fungus has grown, movement can cause the fungus to sink and the fungus has to start all over again.