How do you measure final gravity, or otherwise estimate the correct amount of natural carbonation

[Tim Black]

I come from beer brewing, where original and final specific gravities are measured and the difference tells you how much sugars (fermentables) are left in the brew. This enables you some level of precision when doing natural carbonation in the bottle. If it's too low, you know to add some amount of fermentables in the bottle so it will actively ferment and prodice co2.

But with Kombucha (and water kefir) I'm finding that hydrometers are almost useless. Because of the chemical complexity of these beverages, mainly that there's more acids there, means that the readings are inaccurate.

The batch I just bottled was woefully under-attenuated when I bottled it, and I almost had exploding bottles. Luckily I used flip tops, and was able to open them all and leave for several days, then reclose. Then refrigerate to make all the cultures become dormant.

Does anyone have a best practice for taking these sort of measurements when making and bottling kombucha or water kefir? Most of what I've seen online is a lot of "experiment and find what works for you and repeat." I was hoping for a more scientific method.

Thanks to Lion Heart - I'm using your culture BTW, and love the taste I'm gettting, esp with lots of added raw ginger..

[Michelle]

Do you find the hydrometer to be consistently off (over or under by the same degree) or random?