The most-recent episode of Basic Brewing Radio has got me thinking about making Kombucha.
What would be a typical OG (original gravity) and FG (final gravity) for a Kombucha?
Suggested OGs are around 1020-1030 from a number of forums, but people are making big 1090 OGs.
Regarding FG I recall they end quiet dry as there is often only simple sugars and very little tri-saccharides or longer polysaccharides. so I would expect around 997-1004. What little I can find on the google seems to agree, I have a book at home I will dig it out this evening and see if it sheds more light on this.
Edit: As noted below, you cannot use the OG-FG to calculate Alcohol for Kombucha as it is then further transformed into acetic acid but the acetobacteria in the SCOBY.
I've never measured the OG or the FG, but the recipe calculates to OG 1.014.
The reason why I've never measured the FG is because I just tasted it every so often, and pull it off the SCOBY when it tastes right to me. There is no reason to having booch that's too sweet or too sour; when you're making it yourself, just taste.