Smell is supposed to be a big clue as well. Kombucha generally does not smell nasty (sulphurous): http://www.naturalkombucha.com/how-to-tell-if-kombucha-is-spoi

Smell is supposed to be a big clue as well. Kombucha generally does not smell nasty (sulphurous): http://www.naturalkombucha.com/how-to-tell-if-kombucha-is-spoiled.htm http://www.naturalkombucha.com/how-to-tell-if-kombucha-is-sp... .