His style uses a memorized deck order (named Mnemonica), which is arrived at through faro shuffles with a couple other manipulations to make the deck appear random when it totally isn't.
I own all of his books, and use his techniques, but I'm nowhere near as good as he is at it. It's stunning to watch him, because his zany act is so smooth and casual you'd never know he's doing such complicated shuffles and calculations.
Nearly all his card tricks rely on these two techniques in combination, so he's also mastered getting the deck back into Mnemonica order rapidly while in play as well.
There are other memorized deck stacks out there. Another wild part of Juan's style is that he's calculated how to shuffle between his and other deck stacks on the fly. He's really open about how to do it, because without a significant amount of practice, you're not going to steal his show very easily. By that time, you're already a pro. It's really incredible.
Interestingly, "shuffling" a randomly chosen card to a randomly chosen position without looking is almost purely binary shifts with various adjustments (known as in-faro and out-faro). That part really floored me, but when you dissect how it works, it's pretty obvious. You typically only need up to 3 faro shuffles (and sometimes a straight up cut) in the right order to move any card from one known position to another known position. But it depends on how quickly you can assemble the correct order of operations in your head.
https://www.newscientist.com/article/mg17523525-500-coming-u...