Caffeine adds a whole new level of refreshing to agua fresca, if you ask me! You might ask exactly how this differs from iced chai with rice milk, and that would be a fair question, but really, the texture and flavor due to the ground-up rice are very different from something like Rice Dream (odd to talk about the texture of a beverage, but there it is). This recipe is infinitely variable-try it with another kind of tea, if you like, or a different sweetener, or add some vanilla to the mix. There are also plenty of horchata recipes out there that have you soak and pulverize almonds along with the rice, and I imagine that would be good with some kinds of tea as well. I chose the flavors here-warm chai spice and molasses-because it's winter, and a cold drink must make a little concession to the season. Come summer, maybe some white tea or green with honey will be in order.
One last note: I tried this with both plain long-grain white rice and fancy Italian wild red rice and I tasted no difference whatsoever. Hypothetically brown rice might give you more fiber in this if that's something you care about, but since the solids are strained out it's probably negligible.
I got a basic horchata ratio from http://forkfingerschopsticks.com/rice-5-ways-to-make-horchata-mexicos-rice-drink/ —summersavory
1 1/4 cups
chai tea, loose or in bags, double the amount you would usually use for 1c water
cold water (or milk if you want extra creaminess)
Find a container with a lid that can hold hot liquid and will fit both the tea and the rice. A pint-size ball jar works well. Put your tea bags, or loose tea in a tea strainer, in the container and add the boiling water. Steep the tea for a few minutes to make a nice, strong brew. I used Tea Forte's loose Bombay Chai, a heaping tablespoon, and let it steep for at least 10 minutes. It's alright if the water cools down.
Take out the tea and add the rice. Close the container and leave it on the counter for at least a few hours, or overnight. For brown rice, I left it for about 9 hours and it worked; I left the long-grain white rice for about 5 1/2 hours and that was enough, although longer would have been fine as well.
Pour the rice and tea into a blender jar and blend until the rice is finely ground (I used an immersion blender). Strain the mixture: I poured it all into a dampened bandana, twisted up the corners, and slowly squeezed it to get out as much liquid as possible. A fine mesh sieve might do if you don't mind some graininess. Otherwise, a few layers of cheesecloth should do the trick. Add the cold water (or milk for a bit more creaminess, although I like it with the water) and molasses and stir. Serve over ice, or chill in the fridge and serve cold if you'd rather not dilute it further. It will separate a bit as the rice/starch settles, but a quick stir will remix it nicely.
(If you save the strained-out ground rice, you can use it to make a lovely spiced porridge: I cooked it with some oatmeal and par-cooked quinoa and it was quite tasty. Cream of rice, so to speak.)