I made my first 2 liter of ginger-ale yesterday. I used this recipe, which does not use soda extract, but instead uses fresh grated ginger and lemon juice. I pulled the result from the basement about six hours earlier than suggested because the sides of the pop bottle were already hard. I chilled for about three hours in the fridge (which was not long enough). I opened the bottle slowly, cautiously... nothing happened. I went to pick it up, squeezing the sides in the process, and the bastard fountained all over the cupboard. I think I lost about two cups worth.
I strained the ginger root out of the first taste test. My initial reaction was too yeasty, not enough carbonation. The flavor is good. I like the lemon, and the ginger seems strong enough. I tried the next cup without straining. I actually like the little grated bits of ginger root. They're crunchy, and not as spicy as fresh ginger. In addition, wikipedia tells me that ginger may help reduce arthritis pain.
I'm kind of excited to try making more pop. I haven't been to a brewery supply store yet to look for soda extracts. Austin at BattleAxe Brewing pointed me to some area supply stores, so I'll be checking those out soon. I hesitate to order extract offline until I know what prices I should be looking for, and I've done at least enough batches to tell me I'm going to enjoy doing this more in the future. I still have plenty of ginger, though, so I'll try more of that this week.