Put the teabags and the sugar in a large glass jug or jar that can tolerate boiling water.
Add the boiling water and stir to dissolve the sugar.
Leave to infuse for 30 minutes and then remove the teabags.
Once it’s cool, add the scoby and cover the glass jar with a muslin cloth.
Leave it to ferment in a spot with a steady temperature and away from direct sunlight.
It will become cloudier and slightly fizzy as it ferments; it takes between 5 and 18 days. Taste it when you think it’s ready – it should taste fruity and tart. The longer you leave it, gthe less sweet it will become. It depends how you like it.
Pour the kombucha through a nylon sieve and store in the fridge, ready for drinking. Leave about a quarter in the jar with the scoby to start your next brew.