We buy soda (flavor) extract from the same place I get most of my beer making supplies; they have a pretty good selection. It's pretty cheap - typically it's under $2 for enough extract to make about 5 gallons of soda. Because the soda is (as I make it, anyway) bottle conditioned with yeast, one would not normally make it in that size batch though; you have to condition it for a week or so then refrigerate - or the bottles will explode :) I haven't had this happen yet, but it seems a common theme in online references on the matter. Most recommend using plastic containers, which I have to admit makes some sense.
The process is considerably simpler than beer making; basically you take:
2c sugar 1/8 - 1/4 tsp yeast 1/2 oz flavor extract 1/4-1/2 oz citric acid solution (for fruit drinks) 1 gal waterThe result is very good - easily as good as the $1.50/ea "gourmet" soda from the store.
- Dissolve the yeast in a cup of warm water (wait at least 5 mins to hydrate). Since the yeast is only for conditioning, the type/style of yeast is not particularly important. I use red star bread yeast, since I always have some in the freezer.
- Dissolve sugar in about a pint of warm water
- Add the extract and any citric acid solution
- Add the yeast mixture to the flavored syrup. Add water to bring batch size to 1Gal
- Allow to condition for 2 weeks. Chill before opening.
Batch #1 - root beer Aug 21, 2005
Mixed & bottled Saturday, Aug 21. Opened 2 weeks later; it's good! Didn't measure the extract (!) but tried to eyeball it, which is difficult given the container it comes in. Wound up with too little, so it's not perfect but is very nice nonetheless.