In a small saucepan, add the water and granulated sweetener and place over low heat. Regularly whisk the mixture until the sweetener dissolves. Once the syrup begins to simmer, whisk through the xanthan gum, before removing from the heat.
Allow the syrup to cool completely, before transferring to a glass jar or bottle.
TO STORE: Simple syrup can be stored at room temperature, in a sealed container, for up to 2 months. If you'd like to keep it longer, store it in the refrigerator and it will keep well for up to 6 months. TO FREEZE: Place the jar of syrup in the freezer and store it there for up to 6 months.