What is a "kombucha MOther," "Fungus Japonicus," "mushroom," or "SCOBY*?"
1. Yeast
Yeast are single-celled organisms that "eat" through a process called glycolysis. During this process, the yeast breaks the sugar, sucrose, down into two more digestible sugars, glucose and fructose. All the energy that is gained through glycolysis is used in the continuation of glycolysis or reproduction. Even through yeast reproduce in three ways - by scattering spores, splitting cels, budding - the most common form of reproduction in the tea is budding. During reproduction and glycolysis, the yeast produces the by-products ethanol (an alcohol), minerals, B vitamins, amino acids, sterols, and carbon dioxide. The four most common types of yeast in kombucha are: Pichia fermentans, Kloekera apiculata, Saccharomycodes ludwigii, and Schizosaccharomyces pombe. 2. Bacteria Bacteria are single-celled organisms that need a catalyst to help them eat and reproduce without exhausting themselves. In this case, the bacteria use oxygen, meaning that they use an aerobic process to eat the glucose and fructose that the yeast leave behind, and the ethanol that yeast produces as a by-product. The bacteria then turn the ethanol into acetic acid, giving it a vinegar flavor and smell. There are three types of bacteria that are most common in kombucha. Each of these has a slightly different role in the fermentation process. Acetobacter aceti subspecies xylinum (Brown) comb. nov.: responsible for creating the "pancake" while eating ethanol and oxygen and producing acetic acid. Gluconobacter oxydans subspecies suuboxylans (Kluyver and de Leeuw) comb. nov.: creates gluconic acid while turing ethanol into acetic acid. Acetobater aceti: this bacteria eats the sugars leftover by the yeast and can only digest ethanol if acetic acid is readily available. 3. Cellulose Cellulose is a complex carbohydrate (aka. sugar) that is a by-product of the bacteria's eating and reproduction. Cellulose is what we can see, what makes up the "pancake" and houses the yeast and bacteria. |
* "Fungus Japonicus" is the pharmaceutical name for the mother. SCOBY stands for: Symbiotic Colony of Bacteria and Yeast.