We go through kombucha like water here. I have a 6 gallon continuous brew setup here. My husband and I do about two liters a day between us (though he does drink more than I). Mostly we just drink it because we’ve become addicted to it, and much less for it’s health benefits. We call it “happy bubbles”.
I don’t believe it’s a miracle elixer like it’s toted to be, but it is a wonderful probiotic and does contain a few key nutrients, which can be of great benefit to those who need them. Gut health is pretty well known to be the key to immunity. But it all has to be taken with a grain of salt. It can’t fix a bad lifestyle.
I will say that I find store bought kombucha disgusting, though. The regulating authorities make manufacturers process it to the point of vinegar. You start with sweet tea and add yeast and acetobacter bacteria. The yeast eat the sugar and make alcohol, the bacteria eat the yeast and alcohol and turn it to vinegar. You can drink the kombucha at any point depending on your taste preference. Unfortunately, commercial companies would have to sell it as an alcoholic adult beverage where I like it. Mine comes out at about 1.5-2% alcohol by volume, which is about a third of a generic pilsner beer to put that in perspective. The FDA caps “non-alcoholic” beverages at 0.5% ABV, which means you’re stuck with vinegar if you buy it.
My kombucha is so good we considered selling it, since we’ve plans to build me a commercial kitchen anyway. Our small-town health inspector covers FDA regulating, too, and he was really excited to get us started… But turned out I wasn’t willing to compromise on the flavor to stay within regulations. So now we just trade it with others in our farming community. It works out great. I still get local meats and produce, and it’s legal because no money trades hands.
But yes, carb count can vary a lot. There’s no one strict kombucha recipe, and it also depends on what sort of flavoring is used for the second ferment. I use 14 oz of juice per two-liter bottle of 'buch. After the second fermentation, that leaves about 8g of carbohydrate per one of our 11 oz glasses of kombucha. I haven’t paid much attention to the commercial varieties stats, though, so I don’t know how that compares.
Some of our favorite flavors include “ginger ale” (1/2 tsp ground ginger + 14 oz apple juice + 1 big squeeze of lemon per two liter bottle), elderberry (4 tsp dried elderberries steeped in 14 oz. hot white grape juice + squeeze of lime juice per 2 liter bottle), and hibiscus (prepared the same as the elderberry, but steeped in hot apple juice instead). Soooo good!