What makes Kombucha delectable?

Fermentation is the oldest form of food preservation, dating back to 10,000 B.C. when the first Lacto-fermented milk products were made. Further back in time, in 6000 B.C., wine was brewed. Fermentation is an ancient practice.

Back then, the miracle process was challenging to control and allowed for disorders that could be pretty harmful. The discovery of the microbe behind the miracle process by Louis Pasture was a major medical breakthrough. It resulted in creating a slew of microbes with various applications in everyday life.

Kombucha is an ancient fermented drink. It offers a fascinating culture that has attracted many researchers worldwide.

The unknown facts about this fizzy fermented drink, like what gave it its sweet and tangy taste profile, why it is fizzy, or why it is tagged as non-alcoholic, are a subject to be explored. Let’s find out the answer to such queries.

Table of Content

Who made the first Kombucha in History?

There are two different stories about its origination.

The first mention of the kombucha mushroom was sometime around 221 BC. It became popular in the Tsin Dynasty of Manchuria for its miracle properties. The locals called it Godly Tsche, the Tea of immortality, or the elixir of life.

Later, in 414 AD, a Korean medicine man named Kombu prescribed it to the Japanese Emperor. It traveled to Europe via a trade route through Mongolia and Russia.

In the 1920s, researchers began exploring the potential of Kombucha. However, during World War II, the research was interrupted. The fermented drink became popular much later, in 1960 and 1970.

The source of origin is vague in history. It got the proper recognition in the 20th century.

Ingredients needed to make Kombucha

Like any other fermentation, it requires a starter, inoculum, and a medium.
To develop a healthy culture, you need to provide food and energy for the microbes to multiply and establish themselves.

Sweetened Tea is a medium for microbes to grow and thrive. It is a source of nitrogen and energy. The flavor and texture of Kombucha will vary according to the variety of Tea. Black, Green, and Oolong are the three common varieties.

The fermentation process in Kombucha manufacturing

Kombucha fermentation is a combination of aerobic and anaerobic processes. It requires a symbiotic culture of Yeast, Acetic acid Bacteria (AAB), and Lactic acid Bacteria (LAB). The culture is known as SCOBY (Symbiotic culture of bacteria and yeast. They share a symbiotic relationship; one needs the other to thrive. The concomitant is not constant, varying with the different interfering factors. Yet, some species are predominant.

Yeast-
The following stains of yeast are predominant, like Schizosaccharomyces species, Brettanomyces spp., Saccharomyces spp., and Zygosaccharomyces spp., and there is also Pichia spp.
AAB-
It is an aerobic bacterium. The predominant species are Komagataeibacter, Acetobacter, and Gluconobacter.
LAB-
Lactic acid bacteria make up a small percentage compared to yeast and Acetobacter. The species are: Lactobacillus and Leuconostoc.

Role of microbes in the making Kombucha

The yeast breaks down the sucrose of the sugar into glucose and fructose. Which eventually converts to ethanol and carbon dioxide. This process takes place without oxygen under anaerobic conditions.

AAB carry on three types of reaction;

• Converts glucose into gluconic acid.

• It acts on ethanol to produce acetaldehyde, which leads to the production of acetic acid.

• Converts glucose into cellulosic network or biofilm or pellicle.

A mixture of acetic acid, glucuronic acid, gluconic acid, and traces of lactic acid gives Kombucha its characteristic sour taste.

What is a Biofilm?

The biofilm is a matrix of microbial cellulose containing dormant microbiota.

The acetic acid bacteria undergo surface fermentation or static fermentation, where the colonies grow into a cellulosic matrix on the surface under the influence of atmospheric oxygen. However, it can thrive in anaerobic conditions of the medium along with the yeast.

Initially, the fibers are thin microfibers. As the fermentation proceeds, the fibers form a thick mat-like structure from superimposed microfibrils. It starts to slide downward and traps the bacteria inside of it. The sudden lack of oxygen makes them dormant.

The thick mat is called the pellicle or tea fungus. Most biofilm is composed of AAB, with some yeast mixed in. Eventually, it separates from the liquid.

What is a starter tea?

After the tea ferments, it separates into two layers.

• Into a thick biofilm layer called a pellicle, also known as tea fungus, which floats on the surface and is partially submerged like an iceberg.
• Into a liquid layer of fermented Tea.

Thus, the SCOBY (symbiotic culture of bacteria and yeast) is present both in the pellicle and the liquid medium. The liquid medium is either filtered to create a clear drink with the desired microbial flora or mixed with the pellicle to become a starter culture or starter tea.

How can you make Kombucha?

Primary fermentation;

• Add the starter tea with the pellicle to the fresh, sweetened Tea.
• Incubate the admixture at 20 to 30 degrees Celsius for 7 to 14 days.
• Filter the fermented liquid.
• To make starter tea, combine one part liquid with one part pellicle.
• Use the other part for the secondary fermentation.
• The first bite is bland and doesn’t contain any flavor.

Secondary Fermentation;

• Transfer the filtered liquid to bottles and allow it to stand for a few days.
• It will develop the Kombucha’s distinctive flavor and fizziness.
• At this stage, add the flavoring or fruit juices as an enhancer.

How to determine the end point of Primary fermentation?

Knowing the perfect end point of primary fermentation is crucial for preventing the overproduction of acid and a change in taste profile.

There are two determining tests. The first is a gravity reading, which estimates the amount of sugar remaining compared to how much was in the wort before it was fermented. The second method is to measure the final pH of the beverage. Sensorial attributes like taste and flavor can be an observatory method.

Does Kombucha fall under the Alcoholic beverage category?

US FDA has assigned three terms that define an alcohol-containing beverage.

• Wine- Any beverage that contains more than or equal to 7% and less than or equal to 24% alcohol content falls under this category.
•  Dealcoholized Beverage- Defined as a drink whose alcohol content should not exceed 7%.
•  Non-alcoholic Beverage- Defined as any sparkling or carbonated drink with some alcohol due to its added flavor or color. The alcohol content of such a beverage must be less than 0.5%.

Though Kombucha undergoes an alcoholic fermentation, the final product contains less than 0.5% alcohol by volume. Thus, it falls under the category of non-alcoholic beverages.

Consumers are drawn to kombucha tea thanks to its delicious taste and its ancient history of being used as a curative. It is important to have careful conversations and conduct research studies to understand the healing powers of kombucha tea.

Citations:

• Silvia Alejandra Villarreal-Soto, Sandra Beaufort, Jalloul Bouajila, Jean-Pierre Souchard, and Patricia Taillandie, Understanding Kombucha Tea Fermentation: A Review, Journal of Food Science, 2018, Vol 83, pp. 580-587
• Nyhan, Laura & Lynch, Kieran & Sahin, Aylin & Arendt, Elke, Advances in Kombucha Tea Fermentation: A Review, Appl. Microbiol., 2022 10.3390/applmicrobiol2010005.
• Prashant R. Chawla, Ishwar B. Bajaj, Shrikant A. Survase and Rekha S. Singhal, Microbial Cellulose: Fermentative Production and Applications, Food Technol. Biotechnol., 2009, Vol 47 (2), pp. 107-124.
• José M. Guillamón, Albert Mas, Alfonso V. Carrascosa, Rosario Muñoz, Ramón González, Acetic Acid Bacteria, Molecular Wine Microbiology, 2011, pp. 227-255
• Herald W. Tietze, Kombucha – The Miracle Fungus, Tietze Publication.