Kombucha is fermented tea! It has been around in one form or another for nearly 2,000 years. First brewed in China, it then spread to Japan and Russia. In the early 20th century, it became popular in Europe — following World War One, soldiers brought it back from Russia to Germany, Poland, and elsewhere.
It is a healthy and refreshing beverage full of B vitamins, organic acids, antioxidants, and trace amounts of alcohol.
To make kombucha, starter liquid and a “kombucha mother,” or “kombucha mushroom,” also known as SCOBY (Symbiotic Culture of Bacteria and Yeast) is added to sweetened tea. After a fermentation period lasting 10-30 days or more, the liquid becomes increasingly tart. The sugar and tea are the primary food sources for the bacteria and yeast in the fermentation process.
The yeast in the SCOBY floating on the surface of the liquid ferment the sugar and produce alcohol while breaking down the sucrose into glucose and fructose. Simultaneously, the bacteria feed on the trace amounts of alcohol and convert it into beneficial acids and nutrients, producing a pleasant, healthy, and naturally carbonated drink. Yeast and bacteria consume the nitrogen from the tea and carbon from the sugar to make kombucha.
Once the primary fermentation ends, many home brewers and commercial brands flavor the kombucha with fruits, herbs, or spices and allow it to undergo secondary fermentation. This is when additional carbonation–a natural effervescence–will occur. Many brands also add CO2 to the final product for consistency and stability. Kombucha is known for its expansive flavor profiles that range from fruity to earthy to medicinal and savory.
The public and the scientific community have accepted fermented foods as functional foods. In the case of kombucha, fermentation not only yields delicious flavors but also increases antioxidant content, improving the health-promoting capacity of the tea.
Finished kombucha typically has a pH range of 2.5 to 3.5. However, many commercial brands actually skew a little higher — likely to satisfy the mainstream consumers’ palate, which doesn’t tolerate sour as well as a home brewer might. The fermentation produces a beverage with some natural carbonation, organic acids, nutrients in natural form, and trace amounts of alcohol. In the USA, the current legal limit to be considered a non-alcoholic beverage is 0.5% ABV. Many who avoid beer, wine, or other alcohol find kombucha a refreshing and safe alternative.
There are many types of commercial kombucha. They range from pasteurized or filtered shelf-stable kombucha to ‘raw’ or ‘authentic’ natural kombucha. Natural kombucha needs to be kept refrigerated since it is biologically active. The fermentation process continues as long as bacteria and yeast have sugars to feed on. Yeasts are temperature sensitive, and cold temperatures keep them less active. Trace amounts of ethanol are naturally produced by the fermentation process as a preservative to prevent mold and other pathogens from feasting on the delicious sweet tea. Keeping kombucha cold is an important means of ensuring the quality remains consistent and compliant.
It is easy and fun to brew kombucha at home for a fraction of the cost of commercial kombucha. Check out our Resources page for supplies.