Sparkling Ginger-Lemon Soda

Directions

1. 1
   Combine ginger and 2 quarts cold water in a large pot.
2. 2
   Cut lemons in half and squeeze into pot, straining out pits.
3. 3
   Drop lemon halves into pot and bring to a boil.
4. 4
   Turn off heat, cover and let steep 30 minutes.
5. 5
   Stir in honey, then taste for sweetness, adding more to taste.
6. 6
   Strain mixture into a container and discard solids.
7. 7
   Let cool to room temperature, then chill until very cold.
8. 8
   Working in small batches, pour cold mixture into the bottle of a carbonator, filling it not more than 1/3 full (this will give the mixture room to foam).
9. 9
   Charge with CO2 until very fizzy, waiting between charges for foam to subside completely.
10. 10
    (This can take up to 2 minutes, so be patient.)
11. 11
    Very slowly, as if opening a bottle of soda, release the bottle from the carbonator.
12. 12
    Serve immediately, or cover tightly and chill.
13. 13
    (Extra soda mixture can be refrigerated for up to a week, and can be served carbonated or flat.)
14. 14
    To serve, pour over ice and top with a mint sprig.
15. 15
    If desired, add a slug of rum to each glass.