However, the sugar in Kombucha is for the culture to consume, not for you. When done fermenting, there will be about 2-6 grams per 8 ounce glass of unflavored Kombucha. By contrast, an 8 ounce glass of orange juice has about 24g of sugar.Even natural carrot juices have 13g per 8 ounces.ost sugars are fine for Kombucha (with a few exceptions, see below), but there are preferred choices: 1  Plain White Sugar – the Kombucha culture consumes this easiest. 2  Use only “cane sugar” to avoid GMO beet sugar. 3  Concerns about trace toxins in white sugar processing should be considered.