I am not going to post a horchata recipe until I get it right. But in case you are experimenting, here's my advice: do not, NOT, use basmati rice as your base. I made a pitcher of it yesterday, with much blending and straining and squeezing, and when it was all done, it has a distinct basmati-ish popcorny flavor. That may be a nice thing with Indian food, but believe me, it is not what you want in horchata.
Why did I use basmati rice in the first place? Yankee thriftiness, I suppose. Basmati is all I have on hand because one day I was shopping at the Indian market and decided to spend $15 on a 10 lb sack of the most beautiful, long-grain basmati I had seen.
When I got to the counter, the shop owner pointed to a sign "Two for the price of one." So I ended up with 20 lbs of rice.
There are only two of us in the household. Despite over a year of eating what is, for us, a fair amount of rice, I still have about 4 lbs left. I just haven't been able to bring myself to buy other kinds of rice when I have so much basmati in the house. Thus, popcorn horchata. Ya think maybe I should just bust out the dollar for some other kinda rice?