Specific Gravities for Kombucha

There doesn't seem to be much technical information on OG and FG for kombucha. I'm currently trying to grow a mother from store bought GT using one of the directions from a posted links on this forum. I'm guessing that the scoby will totally ferment out all sugar since there are only simple sugars being used. Does anyone have SG readings for sweet, semi-sweet, and dry kombucha? I'm guessing that dry kombucha can be bottle with similar amounts of priming sugar to that of beer since you can only get so much CO2 from a specific amount of sugar. Any data out there?

Has anyone tried wort with a scoby to see if the scoby will break down more complex sugars?

I found this on the Mad Fermentationist's site:

Certainly fine to use wort for kombucha, but take a gravity reading and water it down to around 1.020-1.030 to make sure it won't be too strong.

I think it depends on what exact cultures are in the SCOBY, I'd imagine. If you have Brett as the yeast, yes maybe some more complex sugars could be broken down. But I've never heard of Acetobacter (the main kombucha bacterial culture, from what I've read) as breaking down complex sugars; doesn't mean it doesn't though.

You could do a test batch using the same amount of DME and same OG in two small batches, one with Sacch and one with a SCOBY, and see if the kombucha has a lower FG. If you do do this, I hope you'll report back

nate_ive said:

There doesn't seem to be much technical information on OG and FG for kombucha. I'm currently trying to grow a mother from store bought GT using one of the directions from a posted links on this forum. I'm guessing that the scoby will totally ferment out all sugar since there are only simple sugars being used. Does anyone have SG readings for sweet, semi-sweet, and dry kombucha? I'm guessing that dry kombucha can be bottle with similar amounts of priming sugar to that of beer since you can only get so much CO2 from a specific amount of sugar. Any data out there?

Has anyone tried wort with a scoby to see if the scoby will break down more complex sugars?

Click to expand...

I make mine stupid strong, I shoot for about 1.092 and let ferment dry (20-40days). You could do all kinds of things from there. If you want it weaker; dilute with tea. You can bottle carb, you can back-sweeten (if you realize the potential for bottle bombs).

[edit] Ignore me, I can't read (and there doesn't seem to be a 'delete post' option?)

mccann51 said:

I think it depends on what exact cultures are in the SCOBY, I'd imagine. If you have Brett as the yeast, yes maybe some more complex sugars could be broken down. But I've never heard of Acetobacter (the main kombucha bacterial culture, from what I've read) as breaking down complex sugars; doesn't mean it doesn't though.

Click to expand...

A SCOBY mainly acts by the yeast fermenting the sugar into ethanol, which the Acetobacter (can include various strains, but Acetobacter xylinum is always present, and its production of cellulose is the source of the SCOBY's characteristic structure) metabolise into acetic acid. Some breakdown of sugars may be done directly by the Acetobacter; these bacteria vary in what sugars they can metabolise, but most can handle arabinose, xylose, ribose, glucose, galactose, and melibiose; while a significant group can also handle mannose and trehalose. Breakdown of other sugars will be almost entirely reliant on the action of the yeast (which often includes Brettanomyces, so I would expect most SCOBYs to have the ability to utilise complex sugars).

I agree . It will just take more time, reason being using honey or other types of sugar.The more complex the more time, but still eventually will get eaten.

I’m bringing back an old thread. So my wife makes kombucha and her recipe is one cup (approx. 7 oz. sugar) in one gal. of tea. I didn’t take a S.G. but I’m guessing it should be about 1.020. When it is done should it be 1.000?