Intro to Brewing Kombucha in the Vessi

Kombucha is a sugar-sweetened fermented tea that is a sour carbonated beverage defined as:  a fermented beverage made from brewed tea and sugar. The taste is slightly sweet and acidic and it may have residual carbon dioxide. Kombucha is consumed in many countries as a health beverage. It is believed to have prophylactic and therapeutic benefits toward a wide variety of ailments (Greenwalt, Steinkraus, & Ledford, 2000).

Thought to have originated from ancient eastern / central Europe it has risen in popularity since the mid-1990s. It's a beverage that is like a cidery/vinegar-like sparkler. Like vinegar, it is a yeast fermentation of sugar to alcohol followed by a bacterial fermentation of alcohol to acetic acid.  You can drink it in its unflavored phase, with or without carbonation, or can add the fruit, vegetables or herbs; fresh, juiced or dried. Sweet, spicy or savory, the variations are limitless and that is the fun of making your special batch. 

In the commercial market, kombucha has become a dominant beverage in the low or no-alcohol industry.  There are several national brands, dominated by heavy hitters like GT Living Foods, Kevita, Brew Dr. Kombucha and HealthAde, bottles of these favored drinks average $3.00 for a 15 ounce bottle. The growing interest in these alternative drinks has led the global kombucha market to be valued at $1.4 billion US$ in 2020  and is expected to reach $8.1 billion US$ by the end of 2026 (source).  

If you’ve tried kombucha, you know and may love the drink.  If you haven’t tried it, you will find that first drink to be an acidic, somewhat vinegary and surprisingly refreshing beverage. It is fermented with sugar-sweetened green or black tea (camellia sinensis) and a starter known as a Symbiotic Culture Of Bacteria and Yeast or SCOBY.  The SCOBY is a rubbery disk which needs to be accompanied by a quantity of starter liquid (fresh-fermented kombucha from a previous batch). It is the starter liquid which will work closely with the SCOBY to get the fermentation process started. 

The black or green tea infusions start at a pH of ≤5. Once fermentation starts, that pH is reduced in approximately seven - 10  days (in a 1 gallon brew) to a finishing pH of ≤2.5, somewhat similar to the pH reduction of wort to beer fermentations (source).

Having an acidic pH range of 3.5 to 2.5, adding the starter to the sweet tea protects the brew from mold or other harmful microorganisms. Acting as an inoculant, the starter liquid works to get the brew quickly activated. 

Topping out naturally at around 2% alcohol, (mine tested in at 2% alcohol) you’ll find it to be an easy to drink beverage.  If you are interested in an alcoholic drink, you can manage your brew to contain some amount of alcohol.  Yeast and hops bring additional flavors to the brew and can result in increases of 3 to 14% ABV.   You may want to try kombucha beer, wine or even champagne in your Vessi experiments. Another option is using kombucha as a base for cocktails. 

Want to try a kombucha brew in your Vessi? Locate a good black or black/ green tea, SCOBYs and starter liquid (lots of it for a Vessi 5 gallon tank full).  Don't forget the flavorings if you want to experiment!  Sweet, spicy or savory, think of a special combination to intrigue your guests.  We’ll get into the specifics of brewing in the Vessi in our next segment.  Below is the list of ingredients.

The ingredients for kombucha include: 

  •  sweetened tea
  •  sugar
  • SCOBYs* with kombucha starter liquid
  • Flavorings 

The brew cycle can take anywhere from 18 - 42 days

kombucha in vessi fermentor

Despite using a commercial kombucha to make my first brew, there have been changes in the commercial brew process resulting in weak SCOBYs started from commercial kombuchas, they will not be long-lived and could result in brewing failures.  

A good source for all things kombucha will be Kombucha Kamp. A source of SCOBYs, smaller brew vessels, teas, dried fruits and other flavorings.  They also authored The Big Book of Kombucha, a reference with instructions, recipes, science and more.  Check them out at:

Note: in your search for SCOBY and starter liquid, do not use:   dehydrated or refrigerated SCOBY; a SCOBY without starter liquid; vinegar as a starter liquid or commercial kombucha as a starter liquid. 

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mary margol

Mary Margol

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