Re: Kombucha & Calories

[Guest guest]

Hi, ,

Thanks for trying out the hydrometer. I'm just playing around with this

stuff, but I think I have a handle on how the hydrometer works, and why it might

be giving the paradoxical readings for KT.

You said you were getting increased hydrometer readings for the mature brew

even though it was getting more sour. I had exactly the same results. And it

is totally the opposite of what I would expect IF I were making beer or wine.

But I think I've figured it out. The key thing is that the hydrometer is

NOT measuring the amount of sugar directly. It's measuring the Specific Gravity

(thickness? density?) of the liquid. The more sugar that's dissolved in the

liquid, the higher the Sp. Gr. So how could a mature brew, with less sugar

remaining, have a higher Sp.Gr.??? The only way is if something other than the

dissolved sugar is increasing the Sp.Gr. of the liquid. Well, how about the

developing SCOBY? When I look at my glass jar from the side, I can actually see

" stuff " trailing down from the SCOBY. And what about all those slimmy little

baby SCOBY bits? Might they be " thickening the soup " and increasing the Sp.Gr?

If so, then the mature brew would have a higher Sp.Gr. but less sugar than the

original mix.

Regarding alcohol content, I also had hoped to be able to measure that based

on hydrometer readings. But, once again, kombucha is too complex a process.

The theory behind calculating alcohol content for beer and wine making is that

the sugar is simply converted to alcohol. So you see how much sugar is gone,

and you assume that the sugar is now converted to alcohol. With KT, it's a lot

more complex. The sugar is converted to alcohol by one part of the culture, but

another part of the culture converts the alcohol into the various good things we

like in KT, including the new SCOBY. So this secondary conversion process

probably makes it impossible to calculate alcohol content based purely on

changes in Sp.Gr.

So, bottom line, I'm a little disappointed that I won't be able to calculate

calorie content OR alcohol with my hydrometer. Those are the first two

questions that everyone new to KT asks when I tell them about it. But I at

least know the upper limit. And as you said, it's not bad compared to most

fruit juice and soft drinks on the market. The recipe that I use calls for 2 C

sugar per gallon of water. If I have my math right, that comes to 96 calories

per 8 oz cup at the beginning of the brew process. Some of that sugar is gone.

And, assuming that the probiotics, vitamins, SCOBY slime, etc. is calorie-free,

the end calorie count is less than 96 cal per cup.

I'm going to continue to play around with the hydrometer, measuring the

brew at different points to see if I can see any pattern. Maybe when it gets

really acidic the Sp.Gr. will fall again. But it's just for fun. Maybe I'll

have to take up beer brewing to get to use my hydrometer as intended.