Well, the soda water part is not homemade.
Here’s the recipe for the ginger syrup to add to some sparkling water. It makes wonderful ginger ale.
Next time I’ll cut the pieces of ginger smaller or thinner so the syrup soaks in more evenly. I ate one of the pieces of ginger that would normally be thrown away and it was wonderfully intense, but would have been better if the center of the piece also had some sugar soak into it.