| By Greg Luli |
You’ve probably noticed over the last year or so kombucha has exploded onto grocery shelves everywhere as well as on tap next to your favorite craft beer. In fact, we also just started offering it fresh on tap here at Cafe Virtuoso. While many people know about kombucha, it’s still relatively new in mainstream culture, despite it being around for thousands of years. The reason that so many people are now consuming it on a massive scale is not just because of its refreshing taste and effervescence, but also because of its many health benefits.
I am a huge fan of kombucha, and as microbiologist, I tend to geek out a bit on the specifics of how it’s made and what it can do for our overall health. I’m hoping this blog will help shed some light and satisfy the curiosity of others by providing more information on what exactly is kombucha and why everyone is drinking it.
Simply put, kombucha is fermented sweet tea. Traditionally black or green tea was used, but today many different types of teas and tisanes are used. It was discovered centuries ago when someone’s sweetened tea became contaminated and they liked the resulting taste. The microorganisms that grew in the sweet tea converted it into something tart and bubbly. Rather than discarding it, the beverage was accepted and various methods were sought to reproduce it. The earliest records indicate the origin was China at least 2000 years ago, although the precise origin remains unknown.
Kombucha is the result of a two-step symbiotic process carried out by yeast and bacteria. It is symbiotic because each step makes the other step more efficient enabling the two cultures to out-compete other microorganisms.
The sugar(s) present in the sweet tea are fermented to ethyl alcohol by a yeast. The number and types of yeast present vary significantly between kombucha cultures. The most predominant is of the Saccharomyces and Zygosaccharomyces families, whose members include brewers and bakers yeasts. Fermentation of the sugar produces alcohol and carbon dioxide gas (bubbles).Yeasts are very efficient in this fermentation at room temperature, consuming it faster than other organisms.
The ethyl alcohol is oxidized by bacteria to acetic and gluconic acids. The predominant bacteria are members of the Acetobacter and Gluconacetobacter families. In addition to oxidizing alcohol to acetic acid, they also convert some of the sugar to the biopolymer cellulose. It is the cellulose polymer that floats on the top of the co-culture providing a home for both of the cultures. The acids produced by the bacteria lower the pH of the tea which provides a favorable environment for the yeast. Also, the alcohol produced by the yeast is ultimately toxic to them. Conversion of the alcohol by the bacteria eliminates the toxicity allowing the yeast to continue their rapid sugar consumption.
The process takes about a week to 10 days for the fermentation of 10% (weight to volume) sugar sweet tea into kombucha. The process is carried out stationary at room temperature. Making the process very each to do at home. The duration is dependent upon the kombucha culture, amount and type of tea, temperature, and the amount and type of sugar added.
There are many health benefits attributed to consumption of kombucha, including:
- Detoxification – The acids and enzymes produced by the kombucha cultures aid in your body’s natural detoxification process. The gluconic acid produced by the bacteria has been associated with preventing certain cancers.
- Combat Arthritis – Kombucha cultures produce glucosamines that aids in building and preserving joint cartilage.
- Digestion – The two cultures provide many benefits of probiotics for the digestive tract.
- Energy – Many people report improved energy levels from kombucha consumption.
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An industrial microbiologist—both by education and for 30 years by trade—Greg is intrigued and challenged by the endless intricate nuances, methods and scientific knowledge needed to roast and brew specialty coffee. If he’s not outdoors hiking with his dogs, he can most certainly be found helping to perfect the roast levels of the newest coffee bean varieties to arrive.