It’s Alive!

Doctor Feelgood’s very own traveling respiratory therapist explains exactly why you should be drinking kombucha.


Home-brewed kombucha

Home-brewed kombucha

THIS ARTICLE IS written in honour of the jar of organic, local kombucha that is now laying sideways on my floor near a dark pink stain of its former contents – a helpless victim of my clumsy foot. In the writing of this article, I hope to inspire myself to reboot my quest to grow my own kombucha SCOBY as much as I hope to inspire you to try drinking kombucha (or kvass, or kefir) for yourself.

Let’s get down to business! Let’s say that the Business is to run your body smoothly, and the Businesspeople are the approximately 1.4 kilograms of (or 100 trillion) bacteria that sit around the boardroom table that is your gut. Their specialities run the gamut of niche duties from maintaining an acidic environment that reduces harmful bacteria (the Competition, in our extended metaphor) to exciting the white blood cells of our immune system. To further their effectiveness, heighten morale, reduce turnover rates, and aid the recruitment process, the consumption of fermented foods is recommended.

Home-brewed kombucha with SCOBY

Home-brewed kombucha with SCOBY

The “modern” science of kombucha is just taking flight, as even though its history stretches back through the ages, we are just alighting onto its medicinal benefits in our culture, which demands verification by scientific study.

One such study by Cornell University in the early 2000s proclaimed that the key component of kombucha is not its tea-derived antioxidants, or its vitamin content, but its acetic acid, which has significant anti-microbial activity. The test batches of kombucha contained acetic acid but no lactic acid (another helpful acid, and a byproduct most commonly produced by lactobacilli), and were tested for their antimicrobial activity in comparison to their brethren unfermented tea, and showed significantly greater activity against pathogenic bacteria of various strains.

This lead researchers to believe that the most active component of kombucha is the acetic acid, which is the final product of a dramatic chain of events wherein the sugar added to the brew concoction is broken down into glucose and fructose, which are further broken down by the yeasts into ethanol and carbon dioxide (i.e. carbonation, if you bottle it properly!). The bacteria acetobacter xylinum happily oxidizes the glucose into acetaldehyde, and then into acetic acid. The fructose is somewhat interesting to the microorganisms at play, but largely remains whole in the fermenting broth, giving a light sweetness. This dance and chain of events is what gives the ‘SCOBY’ its acronymic name: a Symbiotic Culture of Bacteria and Yeast. What you ultimately consume cannot yet be written in stone by our scientists, nor standardised by common kombucha brewing methods, including the continuous brewing method, which re-utilises a growing SCOBY, batch after batch. This is because the components at work are alive, and therefore constantly changing!

One of the locally available kombucha brands

One of the locally available kombucha brands

More recent studies have identified a new bacteria, gluconacetobacter, that is more prevalent in kombucha than its co-star (and former lead talent) acetobacter. Both have similar actions in their creation of acetic acid and their contribution to the pleasant but inescapable “vinegar-y” taste most kombuchas present to the palate.

Try tasting some varieties of kombucha brewed in your area, or make your own! By taking a raw kombucha beverage and keeping it in a lightly covered, wide-mouth mason jar in a warm place for two weeks, you can grow your very own SCOBY to begin your brew-venture, should you dare. Just don’t leave it on the floor.


You’ll never be bored! CHRISTINE RIGBY





  • Marsh AJ, O’Sullivan O, Hill C, Ross RP, Cotter PD. Sequence-based analysis of the bacterial and fungal compositions of multiple kombucha (tea fungus) samples. Food Microbiol. 2014;38:171–178. doi: 10.1016/
  • Jayabalan R, Malini K, Sathishkumar M, Swaminathan K, Yun S-E. Biochemical characteristics of tea fungus produced during kombucha fermentation. Food Sci Biotechnol. 2010;19:843–847. doi: 10.1007/s10068-010-0119-6
  • Ai Leng Teoha,, Gillian Heard, Julian Cox.(2044). Yeast ecology of Kombucha fermentation. International Journal of Food Microbiology, 95(2), 119-126. doi:10.1016/j.ijfoodmicro.2003.12.020



* Christine is a licensed Respiratory Therapist whose only medical practice is upon her own personal biome, as she continues to discover what it means to be human by doing it every day. Christine works at a small start-up and a large bike company in Auckland, where she can be found carefully launching down its volcanic mountain roads and dodging prehistoric driving habits on her bicycle.This is her second blog for Doctor Feelgood.

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