■ 🕑 5. │ Lots of info to consider. What │ does the term "dry" mean to you? │ I have heard it in the context │ of beer, like Asahi "super dry". │ Also, I prefer light carbonation, │ just enough to whet the appetite │ and refresh you. Not heavy │ carbonation you would find │ in a lot of commercial soda. │ I think I will take the soda │ water route just to speed up │ my first go at this, though. │ I'll call it "Pohon Beer". │ Maybe I can even add │ jalapenos - plenty of them │ in the building to go around! │ └─■ 🕑 6. Dry = all the sugars have been fermented by the yeast to Co2 gas and ethanol, basically. And they produce a lot more co2 than you'd expect! The contrast to dry, in the context of wine, is sweet: which makes the meaning of "dry" more clear.
There are a number of ways to determine whether dryness has been accomplished, fermentation has ended.
The easiest way is with a hydrometer -- when the specific gravity drops below 0 (eg that of water), most likely all the sugar (which is more dense than water) is gone and has been replaced by ethanol (which is lighter than water). Especially when the standard gravity is below 0 and remains constant for several days, that's a sign the yeast have finished consuming alcohol, and are now cleaning up after themselves before they go dormant and the hooch clears up.
Co2 can still be released from the liquid after fermentation has ended so it's not a 100% sign that fermentation is still ongoing if Co2 is being released.
For me, where ambient temps are 25-32*C, it takes about a week for 5% ABV to ferment with bread yeast (~85g sugar/liter) and then about another week for things to settle out. Higher ABV takes longer to ferment and longer for yeast to clean up after themselves. And you lose flavor.
A cheaper way to see that fermentation has completed: when your airlock goes inactive (either stops bubbling if it's a proper one, or the balloon goes limp and deflates completely, if you go the balloon route) screw a lid on. Check every few hours for the next day to see if pressure is building up: squeeze the bottle to see if it's gotten firmer and unscrew the lid to "burp" out any Co2 (you don't want a bomb going off)
When you test the bottle and no more Co2 is being released in significant ways, after 2 or 3 days of checking, you can move onto the next step.
This is the time when you want to add 5g/liter of sugar and possibly a dash more yeast before sealing the bottle and letting it sit -- I think 10g/liter could be feasible, especially in a plastic soda bottle for a heavy carbonation. But you're going to have to wait at least another week or two for the yeast to clean up after themselves and go dormant, making the drink safe to drink, even though it's only the bit of Co2 you're looking for. Using clear plastic bottles is a great way to check "finishing" because the drink will become very clear when it's ready to drink. When in doubt, wait more -- it only improves the product!
All you can really do is trial and error if you don't want to research about the finer details of carbonation or invest in more equipment. I think 5g/yeast per liter once fermentation is probably a safe starting point. Otherwise, double the ginger and ABV, then cut with soda water when it ferments dry. Takes maybe 2-3 weeks for a drink to be drinkable after starting fermentation, but more time only helps in making things smoother and more subtle.
Whether you add more sugar at the end to produce carbonation the old fashioned way or you plan to mix your dry fermented ginger ale with soda water, make sure to pour slowly from your fermenter -- near the end you'll see the nasty "lees" (dead yeast and crap), you don't want any of that in your final product because it tastes foul and can give you a tummy ache.
I'm only an amateur brewer & distiller but I hope this knowledge can help you. Feel free to update this thread with the results of your experiments. Try to keep logs: date fermentation starts, recipe, ambient temperature, date fermentation seems to end, etc etc. Brewing is an art and a science: either way, notes help.