Re: Is anyone testing the residual sugar in kombucha?

[Guest guest]

By adding frozen wild blueberries to the 2nd ferment, I finally got

one bottle down to 2.5 - 3 % sugar. It was delicious. The ones I

added raspberries to didn't do anything, so I assume the further

fermentation must have been due to yeasts on the blueberry skins.

Obviously, the bookcase I had my kt brewing in has some sort of anti-

fungal in the particle board. At least that's all I can think of.

I have some scobies and starter coming from one of the wonderful

people on this group so that I can get going with continuous brewing.

Meanwhile, this weekend I went to a home brewing supply store and got

some glass jugs (1 gallon and half gallon), a couple of airlocks, and

some Red Star Montrachet Yeast. The yeast is " a strain of

Saccharomyces cerevisiae " used to make dry wine, so it should reduce

the sugar content, I hope.

I put all of my brewed KT that was still sweet (all of it) into the

jugs with some of the yeast, popped on an airlock, and boy are they

ever bubbling. I'll probably end up with KT wine, but if so, that's

okay too.

Best,

Dee

Central Square, NY

>

> I hope I'm not being a pest, but I really, really, really want to

be

> able to drink KT, but because of diabetes, I need to reduce the

carb

> content.

>

> Has anyone tested their tea with a hydrometer to see how low the

> residual sugar can go? I'm hoping to get it down to 2.5% but don't

> know if that's even possible.

>

> Thanks and sorry if I'm bugging anyone.

>

> Dee

> Central Square, NY

>

[Guest guest]

By adding frozen wild blueberries to the 2nd ferment, I finally got

one bottle down to 2.5 - 3 % sugar. It was delicious. The ones I

added raspberries to didn't do anything, so I assume the further

fermentation must have been due to yeasts on the blueberry skins.

Obviously, the bookcase I had my kt brewing in has some sort of anti-

fungal in the particle board. At least that's all I can think of.

I have some scobies and starter coming from one of the wonderful

people on this group so that I can get going with continuous brewing.

Meanwhile, this weekend I went to a home brewing supply store and got

some glass jugs (1 gallon and half gallon), a couple of airlocks, and

some Red Star Montrachet Yeast. The yeast is " a strain of

Saccharomyces cerevisiae " used to make dry wine, so it should reduce

the sugar content, I hope.

I put all of my brewed KT that was still sweet (all of it) into the

jugs with some of the yeast, popped on an airlock, and boy are they

ever bubbling. I'll probably end up with KT wine, but if so, that's

okay too.

Best,

Dee

Central Square, NY

>

> I hope I'm not being a pest, but I really, really, really want to

be

> able to drink KT, but because of diabetes, I need to reduce the

carb

> content.

>

> Has anyone tested their tea with a hydrometer to see how low the

> residual sugar can go? I'm hoping to get it down to 2.5% but don't

> know if that's even possible.

>

> Thanks and sorry if I'm bugging anyone.

>

> Dee

> Central Square, NY

>

[Guest guest]

>

> I hope I'm not being a pest, but I really, really, really want to be

> able to drink KT, but because of diabetes, I need to reduce the carb

> content.

>

> Has anyone tested their tea with a hydrometer to see how low the

> residual sugar can go? I'm hoping to get it down to 2.5% but don't

> know if that's even possible.

You've got the right idea, but the hydrometer test wouldn't be ideal

for the purpose. Hydrometers don't directly measure sugar content, but

rather specific gravity. With a simple syrup, specific gravity

directly corresponds to sugar concentration, as there's nothing else

dissolved in the liquid.

Upon fermentation, specific gravity actually changes very little, as

you're starting with a fairly dilute solution and not removing much in

the way of number of molecules from the solution.

The test you want is called " Benedict's Solution " (invented back in

the day when such things still got named after their inventor -- and I

mean _back_ in the day! *grin*). It's made from sodium carbonate,

sodium citrate, and copper sulphate -- all three readily-available or

producable at home (I did it when I was in middle school), but also

available from educational houses such as:

http://www.pelletlab.com/p_chem1.shtml

ready-mixed. What you'd generally want to do is make a non-fermented

control with sugar and one without sugar (and perhaps, one with a

maximum-allowable amount of sugar -- the point you're shooting for in

your ferment), along with some of your kombucha you're testing.

You'll want to add equal amounts of vinegar to each (just to make sure

they're all acidic) and heat them in a hot-water bath (just-simmering

kettle) for twenty minutes to break down the sucrose into fructose and

glucose. Then you'd add the same amount of your Benedict's Solution to

each sample. What you're shooting for is a colour somewhere between

the no-sugar and minimum-sugar samples with your fermented sample.

It's not as complex as it seems, and you can find many more in-depth

explanations online at science education sites if you wish. Diabetics

(or their families) actually had to perform a very similar test on

rather disturbingly-large samples of blood in the days before easy

blood-sugar measurement. (cf. " The Hiding Place " , Corrie ten Boom)

Cheers!