Kombucha the “Wonderdrink”

by Katie on March 6, 2013

Everyone knows that drinking tea is good for your health but wouldn’t it be great if there were a way to make it even healthier? Well actually, there is! (Spoiler alert, it’s a fungus!)

For centuries, and depending on where you lived, the answer to all that ailed you may have been the so-called miracle drink Kombucha. In fact, Kombucha has long been praised far and wide, thanks in large part to word of mouth testimonies, for the many health benefits this miracle tea may confer. Even today, Kombucha is part of a growing market in health food stores across the U.S. and the world where it is being recommended for treating many ailments, while serving as a refreshing sweet, sour and fizzy soda alternative.

My favorite store-bought variety. Photo courtesy of photopin.com

Kombucha, which is really just fermented sweet tea, got it’s start, however, as a simple home remedy in China during the Tsin Dynasty circa 200 BC. Another two hundred years later, reports claim, Doctor Kombu brought the famed tea to Korea to cure the emperor of his digestive woes. Not long after that oriental merchants brought the tea, sometimes called Kvass, to Russia and eventually to the rest of Eastern Europe around the turn of the century.

I can hear it now… step right up and be the first to try the miracle cure from ancient China! The best home remedy in all of Russia! It cures all! Intestinal problems! The common cold! Allergies! Arthritis! It will make you younger, revitalized, and if you’ve got a problem, kombucha tea can help!

Sounds suspicious and rightfully so. It is never easy to tell what home remedies actually work and what marketing miracles just make you think you are being healthy. Fortunately, modern research has got your back! Researchers have been putting this traditional drink through a gauntlet of tests to find out which claims hold up and what is just your grandmother’s gossip.

Righteously, this drink is one case in which the supposed health benefits cited by word-of-mouth testimony are actually being scientifically proven to be true!

SCOBY Fermentation

How does Kombucha become so good for you? Well, fermentation of course! Humans have been fermenting foods and beverages since the dawn of time. What likely started as a fortunate accident turned into a method of preserving food and drink with ethanol and acid as well as making nutrients more digestible. As a result, some of our favorite foods are fermented; beer, wine, bread, yogurt and the list goes on! But today we are talking kombucha.

Kombucha gets its fermentative power from a SCOBY or a symbiotic culture of bacteria and yeasts. This SCOBY is a mixture of bacteria (Acetobacter xylinum) and yeasts (which vary depending on where the culture originated). These mesh together into a fungus-like disk that floats at the top of the tea.

A SCOBY. I admit, it looks a little weird. Photo courtesy of photopin.com

First the bacteria consume the sugar sucrose and make two smaller sugars, glucose and fructose, while simultaneously producing acetic acid (like what is in vinegar). These sugars are then fed to the yeasts, which use them to produce ethanol (alcohol) and carbon dioxide. The ethanol then stimulates more acetic acid production and the cycle continues. After just 7-10 days the fermentation is done and the kombucha is ready to be bottled.

It may sound dangerous to let your tea grow a fungus for a week and then drink it but when you keep the equipment clean and use the right SCOBY the pH drops so quickly (from pH6 to pH3 in 3 days) that it’s very difficult for any bad bacteria to grow.

So What Does the Science Really Say?

The fermentation process changes the chemical and nutrient content of the liquid so that after a week of waiting and watching the fungus grow in your tea, you have a delicious beverage full of many beneficial nutrients! Of course, the tea you start with is good for you all by itself thanks to the polyphenols (although I don’t recommend adding quite so much sugar to it). Polyphenols are responsible for the antioxidant qualities of green and black tea. However, AFTER the fermentation the finished kombucha has much, much more. Amino acids, vitamins B2, B6, & C, acetic acid, lactic acid, and active enzymes are just some of the important active compounds in every cup of kombucha tea.

Research has shown that because of the changed biochemisty and increased nutrients, kombucha is antimicrobial, antiviral, hepatoprotective, and a very strong antioxidant against multiple types of reactive species. This means that it has a significantly higher concentration of antioxidants than the starting tea. This concentration is enough to combat dangerous free radicals that cause cell and liver damage. Current research also suggests that kombucha has a promising future according to studies that found it to be an effective antibiotic against  E. coli, H. pylori, S. aureus, S. cholerasius and B. cereus.

Kombucha is easy to ferment at home in large jars covered with cloth. Photo courtesy of commons.wikimedia.org.

Of course, this is not actually a cure-all wonderdrink. However, it is fun when science gives merit to the home-remedy claims of old. Drinking kombucha tea can be a beneficial addition to anyones diet although store-bought is expensive and home-brew requires some (not much) extra work. All in all hopefully you are inspired to look into the science behind your favorite fermented foods and maybe even try your own hand at making them. Just remember to always use a reputable culture and clean equipment!

References:

Durfense D, Farnworth E. Tea, Kombucha, and health: a review. Food Research International 33 (2000) 409-421.

Bhattacharya, S et al. Hepatoprotective properties of kombucha tea against TBHP-induced oxidative stress via suppression of mitochondria dependent apoptosis. Pathophysiology 18 (2011) 221–234.

Kallel L et al. Insights into the fermentation biochemistry of Kombucha teas and potential impacts of Kombucha drinking on starch digestion. Food Research International 49 (2012) 226–232.

Malbasa, R et al. Effect of sucrose concentration on the products of Kombucha fermentation on molasses. Food Chemistry 108 (2008) 926–932.

Malbasa R et al. Influence of starter cultures on the antioxidant activity of kombucha beverage. Food Chemistry 127 (2011) 1727–1731.

Dan Kegel March 6, 2013 at 10:16 am

Where’s the beef?

This article did not present any evidence of health benefits. Saying “antioxidants!”
just doesn’t cut it… you have to also show that 4% fewer people died or had fewer pimples or something.

I guess you were aiming for a humorous tone, but it didn’t work for me.

Adam March 6, 2013 at 2:18 pm

I accidentally bought kombucha, thinking it was a really natural-looking fruit juice and not fermented sweet tea.
I was first taken aback by the price – almost $5 for a 20 oz. bottle. Then, when I opened the bottle, I was further taken aback by the odor. I couldn’t stomach a sip after the frightening stench.
Cheers to your health if you can manage a couple swallows!

Jvc March 6, 2013 at 9:02 pm

Katie
Thank you for recognizing kombucha. One has to believe in its benefits for the tea to work for them.

Rick March 7, 2013 at 2:04 am

I live in Japan, where I’ve had konbucha, a “tea” made by brewing konbu/kombu seaweed, several times. I know that konbu seaweed is considered to be very healthy, but I had never realised that the “kombucha” marketed overseas was something completely different.
One question that occurs to me is that, if fermenting is so good, wouldn’t black tea or wulong tea also be improvements on “straight” green tea?

Rick March 7, 2013 at 2:10 am

A couple of other remarks:

It’s good that you’ve included some references, but they’re a little different from what I think of as academic references in that there aren’t any citations in the text pointing to them. In the absence of those citations, the implication to me is that each article listed at the bottom supports every one of your points.

Also, a couple of typos:

anyones diet >> anyone’s diet
it’s start >> its start
some of our favorite foods are fermented; (change the semicolon to a colon, since what follows is a list rather than an additional point)

Rick March 7, 2013 at 2:16 am

Sorry to keep chiming in but, when you’re writing on the Web and the sources you cite are also on the Web, etiquette requires making the references hyperlinks. I didn’t read all of the papers you cited, but I found at least one:
http://www.sciencedirect.com/science/article/pii/S0308814611003074

Rick March 7, 2013 at 2:28 am

Sorry, me again. You got me curious, so I went ahead and ordered some kombucha blended with ordinary green tea, lemongrass, and spearmint. I figure the chances of a blend like that tasting bad are pretty slim, but, since I already know the tastes of the other ingredients, I ought to be able to get some idea of the taste of the actual kombucha.

Angela March 12, 2013 at 8:21 am

Thanks for the interesting post! I have never had any kombucha so far, as I’m a bit paranoid that it may contain alcohol from the fermentation process (I’m allergic against alcohol). What was not quite clear to me is what happens with the SCOBY. Is it discarded, used for something else, or does it become part of the drink? (Frankly, it looks like it should be used in the production of art works…)

Sergey March 21, 2013 at 12:41 am

Very bad. Very very bad.

Russian Kvass has nothing to fo with the subject. It is made from bread and yeasts. We have a kind of beverage from tead. It name is something like “tea fungus”. You shoul check fact you mention.

And those links about hepatopretective and other properties. I just hope that you di understand that they have with real effett of Kombucha on health.

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