At a certain point the water will not dissolve anymore sugar into it without being heated. Stop adding sugar when it won't dissolve anymore into the water.
In addition, if you are truly adventurous/daring you might try adding 2 cups and tasting the mix after it stops fermenting, if it is still sweet (after being shaken up) then too much sugar was added, then just cut the sugar down until you can't taste it anymore and that is the perfect amount to add. The amount of sugar that the yeast can eat without being killed by the alcohol they produce.
I suspect it will be quite a bit less than 2 cups in a 2 liter soda bottle...
...my guess has nearly nothing to do with tasting the moonshine - I mean DIY CO2 concoction myself
In addition, if you are truly adventurous/daring you might try adding 2 cups and tasting the mix after it stops fermenting, if it is still sweet (after being shaken up) then too much sugar was added, then just cut the sugar down until you can't taste it anymore and that is the perfect amount to add. The amount of sugar that the yeast can eat without being killed by the alcohol they produce.
I suspect it will be quite a bit less than 2 cups in a 2 liter soda bottle...
...my guess has nearly nothing to do with tasting the moonshine - I mean DIY CO2 concoction myself
