If you ever need to recarbonate your plain sparkling water, you can. Just make sure that the water reaches the fill line on the carbonating bottle. If you've already prepared a drink with flavor, you cannot recarbonate. Only water should be carbonated in the SodaStream Sparkling Water Maker.
0:031:58How to Carbonate a Flat Beverage - Soda, Water or Any - YouTubeYouTube