My favourite drink – for after a ride – is what in Germany we call “Apfelschorle”, a mixture of apple juice and (carbonated) mineral water. I don’t like to take it with me on a ride (so much) as the carbon dioxide in it tends to balloon the water bottles, but that could, of course, be overcome by shaking the bottles some before putting a tight lid on. And the drink would still retain some of its fizziness, which makes it pleasant to drink and not stale.
A good, i.e. easily resorbed, drink mix should be about one third of apple juice and two thirds of mineral water, plus a pinch [about 1 – 2 grams] of salt. For mineral water choose some that is rich in magnesium, 100 or more milligrams per liter, and with a sodium content of 50 to 100 mg/ltr. Unfortunatley, here in the US I have not seen contents other than magnesium marked on the bottles.
Another energy drink to mix yourself is a mixture of 30 to 80 grams of Maltodextrine and again 1 – 2 grams of salt per liter.
Whatever you do, make sure that the resulting drink is isotonic, i.e. it must neither contain too many carbohydrates nor minerals [less than 80 grams of carbohydrates, with 30 to 50 grams being optimal, and around 450 grams of sodium per liter], so that it will be absorbed quickly by the body.