Welcome to Kombucha Brooklyn!

Sugar, Alcohol, and Kombucha Part 1


All day long we tell people that kombucha is a “fermented tea,” but what does that really mean? I ask this question because there are a lot of assumptions that are made when the word “fermented” is used.


Sugar Without sugar, there would be no kombucha!

In reality, while kombucha is definitely a fermented beverage, it’s not only a fermented beverage. There are various other biological activities that take place inside your humble brew vessel.


But when it comes down to it, regarding fermentation, most people want to know two things: the alcohol content and the amount of sugar in kombucha. These two facets of the drink are intertwined. In fermentation, the higher the initial (pre-fermentation) sugar content, the greater the potential for alcohol content. Fermentation is responsible for turning kombucha from super-sweet tea into the slightly sour, low-sugar beverage we all love - that’s because there are micro-organisms at work consuming and converting those initial sugars, among other things. That’s why your brew will become more acidic and less sweet as it progresses.


Not only that, but every brew is different, and some of the various reasons why this is true would be laborious to measure. ‘Buch fermented on the East coast will be different than one fermented on the West coast, in different homes of the same city, etc., based on subtle differences - the spontaneous contributions of “wild yeasts” that will come into contact with your brew during preparation, pouring, or transference, variations in temperature, minute differences in microbe population of your SCOBY or starter, and the many qualities of the nutrient (or “nute,” the sweet tea that becomes kombucha). Those are just a handful, but it’s easy to consider even more - temperature, atmospheric pressure, available oxygen in your brewing area, ventilation, interrupted respiration from moving the vessel, proximity to magnetism, playing Mozart to your brew, and many others.


When it comes down to it, considerations of sugar and alcohol in kombucha, while correlated, are still based on a number of other variables. This also makes it difficult to come to an across-the-board average on caloric content in kombucha when it’s not produced in absolutely consistent conditions, such as in a brewery or laboratory. But don’t let these considerations scare you away from brewing, it’s still as simple as ever.


In subsequent blogs, I’ll flesh out more of the intricacies of sugar metabolism and inversion during kombucha production. In the meantime, throw back a homebrew, and consider becoming your own ‘buch researcher, and of course be sure to let us know what you find (easy to do with our ‘Buch Brewers’ Group on Facebook).


Happy brewing!

6 thoughts on “Sugar, Alcohol, and Kombucha Part 1”

  • […] alcohol as well as CO2. These can be friends and foes in kombucha brewing for a few reasons. Read this blog for more information on sugar, alcohol and […]

  • […] Culture of Bacteria and Yeast) has become a constant in my fridge. The caffeine is annihilated, the sugar converts to bubbles and a tinge of alcohol (so little that I regularly share this with my kids). What’s left is a cool, flavorful, fun, […]

  • justin

    Hello, I have made my own SCOBYs and kombucha for a number of years. Recently diagnosed with lung cancer, I had let them sit dormamt in my fridge for a year as I was on an immunotherapy drug as well as chemo. Having finished the clinical trial I thought I'd start making my own again. Do However my acupuncturist said K. is just a sugary fermemted drink. Mine was never very sweet. I stopped eating sugar upon my diagnosis but wanted to know what the sugars are in K since I want to watch intake of sugars. Commercial kombuchas have about 2 gr per 6-8 oz. Alcoholic beverages have sugar to help feed the yeasts, but I don't consider brandy or even vodka sugary drinks.

  • Gina L

    What's the best way to measure sugar content after 2nd ferment for those concerned over calories?

    • Chris

      Hi Gina, the best way to measure the sugar would be to use a refractometer. Accurately measuring the sugar in kombucha is not possible with a hydrometer and generally the way I measure is simply with my tongue. Kombucha is chaotic and testing for sugar and alcohol is notoriously difficult. There's a basic discussion of this here. Good luck!

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