Simwaves,
I'm glad you're enjoying the book! I'm assuming that's where you picked up the horchata recipe, I'm not sure that I've posted it anywhere else. Thanks for the compliments. I hope you enjoy the rest of the recipes as well.
Daft,
I do agree that sodas need some acid kick to them. There is something magical about tart, freshly carbed fruit juice. But I don't necessarily think all sodas need to be that way. I lump horchata into the "indulgent" category because bona fide horchata doesn't have any added acid. To each his own, though.