Since the yeast will burn sugar away generating alcohol & CO2 for as long as it can (until the % by volume makes the brew toxic, killing the yeast off), just adding more sugar doesn't seem to the answer.
Although this technically results in a sweeter (sugar remaining after yeast is no longer viable) result, carbonation drops won't work to carbonate in bottles.
How do you get a sweeter result?
For example mead or ginger ale are typically quite sweet; how is this achieved?
Is there some kind of sugar which is not compatible with certain yeast strains?
Can't seem to find any information regarding this type of brew.