One 2 oz bottle (and 4 pounds of sugar) will make 4 gallons of soda using the traditional mix and carbonation method. The detailed instructions provided in the box explain how to carbonate the sodas using dry champagne yeast. If you carbonate with yeast, everyone (including Rainbow Flavors) warns against using glass bottles. There is a real risk that some may explode and cause personal injury. Use plastic PET bottles. Carbonation levels are difficult to control when making soda with yeast. When following the instruction provided, it allows yeast to produce carbon dioxide for three days at room temperature. When the soda is refrigerated, the yeast becomes dormant and CO2 production nearly stops. If the soda is not refrigerated after bottling, pressure will continue to build inside the bottles and the soda may erupt in a gusher when opened. Glass bottles may even explode. Just a word of warning. Soda is fun, easy and safe to make at home, but please be careful.