Put both together in a pot on the stove. Gently combine and stir as they come to a boil. Decrease heat to low and let the liquid simmer very lightly for 10 minutes.

Let liquid cool. Strain and throw away ginger remnants.

Refrigerate ginger water. (I use a small canning jar.)

When you want to make a glass (or more) of the ginger ale, mix 1/2 cup of the ginger water with approximately 1/2 cup of sparkling water and your sweetener of choice. I use 1/2 packet of Stevia but you can also use a tbsp of honey or maple syrup. If sugar isn't a concern for you, you can also use 1/4-1/3 cup of simple syrup, which is 1:1 sugar and water, boiled together for one minute and then thoroughly cooled.