A frequently asked question:
- How long will my brew take?
This mostly depends on (1) the temperature at which it is brewing, (2) the quality of your mother, and (3) the quantity of starter added at the beginning of the brew.
The sweet spot for fermentation is generally around 80°F/26°C. Kombucha brews left in consistently cooler temperatures (down to 65°F/18°C) can take up a month to complete, whereas warmed kombucha brews (up to 85°F) can take no more than three days. Below 64°F/18°C, microbiotic activity slows to a temporary halt -- refrigerated komucha won't brew until it's brought to warmer temperatures again. Brews made between 70-79°F/21-26°C should take one to two weeks; brews made between 80-85°F/26-30°C will take three to seven days. Ferments above 85°F/30°C result in brews that are more acidic, less mellow, and less carbonated.
Different kombucha cultures and mothers will have unique properties due to variation in microbiotic action. Some mothers simply brew slower -- although this is not exclusively indicative of a bad or dying mother, healthy cultures tend to brew consistently at a steady pace; a two-week turnover should be expected from a healthy brew kept at ideal temperatures.
Finally: the amount of starter added at the beginning of a brew can shorter or prolong brew time. The reasoning behind this is simple: more starter means a lower proportion of tea, thus less of that ingredient needs to be processed by the kombucha culture before it is deemed ready for bottling. Some continuous brew systems (in which sweet tea is added to an ongoing brew every few days after a proportionate quantity of kombucha has been drawn out for bottling) average up to 50% starter when tea is added, and thus brew time can be as short as three days. In this case, however, the "starter" is actually kombucha ready to be siphoned off and bottled; this is in contrast to conventional kombucha "starter," which is a prolonged vinegary ferment of tea which has long passed it ideal time for bottling.