I use a mix of maltodextrin powder (try a homebrew shop) and flavored whey protein, mixed about 7:1 by weight. You can get about 750 calories (1 pt.) of this stuff into one water bottle. Or mix it weaker according to your ride length. Quite cheap, especially buying the malto in 50# bags and the whey in 10#. Doesn't seem to rot my teeth, even. The other bottle plain water. Endurolytes (Hammer Nutrition) for electrolytes.