# Kombucha: caffeine, alcohol and hydration facts

Kombucha is fermented tea, so it carries a little alcohol and a little caffeine. What a 330 ml bottle counts for, and what the label does not tell you.

## Numbers the app uses

| Field | Value |
| --- | --- |
| Default serving | 330 ml |
| Hydration factor | 1.00 |
| Counts toward the daily goal | 330 ml per serving |
| Calories | 15 kcal per 100 ml (50 kcal per serving) |

## Two organisms, two by-products

Sweet tea plus a yeast-and-bacteria culture gives you two things nobody put
there. Acetic and gluconic acids are the sourness. Ethanol is what the yeast
makes before the bacteria convert most of it. In the United States a drink can
only be sold as non-alcoholic below 0.5% ABV. Commercial kombucha is brewed to
land under that line. The app files it at 0%, with a hydration factor of 1.00.
A 330 ml bottle is 330 ml toward your goal, the same as water.

The non-obvious part is that the fermentation does not stop when the bottle is
capped. A live, unpasteurised bottle left warm in a car or a shop window keeps
working, and the alcohol keeps climbing. That is not theory. American producers
pulled kombucha from shelves in 2010 after post-bottling fermentation pushed
tested batches over the legal threshold. The industry's move to refrigerated
distribution dates from it. Keep it cold, and not only for the taste.

## The caffeine the catalog sets to zero

Kombucha starts as brewed tea, so a bottle almost always contains some
caffeine. The culture consumes the sugar, not the stimulant. Published figures
for commercial brands are scattered. A bottle can land anywhere from a few
milligrams to something close to a cup of green tea. It depends on how strong
the starting tea was and how long the brew ran. Because there is no reliable
single number, the catalog value is 0 mg rather than a guess.

If your brand prints a figure on the label, edit it. Kombucha sits in the tea
category in the app, so its caffeine field is editable. Whatever you enter
carries into the daily caffeine total from then on.

## Calories, and what it is actually good for

50 calories in a 330 ml bottle makes it about a third of a can of cola. The
yeast ate most of the original sugar, which is the whole reason it tastes sour
rather than sweet. As a hydrating drink it is unremarkable: exactly as good as
water, no better. As a replacement for the fizzy sweet thing you were going to
open instead, it is a straightforward 90-calorie saving with the carbonation
kept intact.

## Source

Hydration factors follow the Beverage Hydration Index. Maughan RJ, Watson P, Cordery PA, et al. “A randomized trial to assess the potential of different beverages to affect hydration status: development of a beverage hydration index.” American Journal of Clinical Nutrition, 2016;103(3):717-723. https://pubmed.ncbi.nlm.nih.gov/26702122/

Page: https://waterchamp.app/drinks/kombucha/