Classic kombucha on black tea

Pour black tea (25 g) with water (500 ml), bring to a boil and immediately turn off the heat. Add sugar (165 g), stir until dissolved, cover with a lid, and let it cool completely.

Sugar is needed here for the kombucha culture: the yeast and bacteria will consume most of the sugar during fermentation. The exact amount of residual sugar depends on the temperature, the strength of the starter, and the duration of fermentation. For keto, ferment the drink longer until the sweetness noticeably decreases, drink in small portions, and if the taste becomes too sour, add erythritol after fermentation.

Strain the infusion through a fine sieve or cheesecloth. Add bottled water (1800 ml) so that the total volume of the infusion is about 2.3 liters. Aim for a temperature of around 30 °C.

Transfer the infusion to a three-liter jar. Place the kombucha culture (1 piece) with the yeast side down and add a few spoonfuls of starter from the previous kombucha.

If you don’t have a starter, use 100-150 ml of ready unpasteurized kombucha without sugar and flavorings.

If you don’t have that either, leave the culture in sweet tea for a longer fermentation and rely on smell and taste: the drink should become sour, without mold or unpleasant odors.

Cover the jar with a paper towel, secure it with a rubber band, and leave it at room temperature (18-23 °C) away from direct sunlight for 5-6 days.

Strain the ready kombucha through a plastic sieve. Transfer part of the drink and the culture to a clean jar for the next batch, and pour the remaining kombucha into bottles. For carbonation, leave the closed bottles at room temperature for 12-24 hours, then move them to the refrigerator.

Do not add sugar before carbonating if you are making a stricter keto version. Open the bottles carefully, gradually releasing the gas.