SCOBY refers to a Symbiotic Culture Of Bacteria and Yeast which is used to produce Kombucha through the fermentation of sweet tea.
White Labs' SCOBY does not contain any food pathogens, and has been genetically identified to know the exact yeast and bacteria involved in Kombucha fermentation. This particular SCOBY has low alcohol production and has medium acetic acid production.
One White Labs SCOBY packet has enough starter to produce 1 gallon of Kombucha. If you would like to produce more than 1 gallon then you will need more starter liquid. Previously made or bought Kombucha will work as a starter liquid as well.