I've been drinking it at home for a while now. I really love it. It tastes very different from roasted coffee, so don't try to compare it.
I think much like one wouldn't compare yogurt and whipped cream.
And later in the stomach it feels much better than roasted coffee.
The amount of caffeine is about the same, for the same amount of original beans (their volume and weight changes during roasting, so don't compare by weight).
For preparing I think the main difference in the brew is that it needs a longer cook than roasted beans, because the green are harder (or tougher), it takes more time to soak out their juice. So for example you can't do a quick extraction like in espresso machine.
Another thing, you should not use cold brew - you shouldn't drink coffee absolutely raw - it must be heated at least once. So roasted coffee is already cooked, and you can do cold brew, but green coffee must be cooked before it's drunk. I'm not sure how bad raw coffee would be to your health wise, I heard somewhere on the web that it's bad, I dunno, it tastes like shit, and I wouldn't try it myself.
Preferably grind beans first (buy them ground, they're really hard to grind), because it extracts more efficiently.
Basically just cook the grounds/beans in water, and then drink the water.
- i cook for 60 minutes in a pot on lower than boiling temperature, the closer you get to boil temperature it gives a somewhat different taste, but it's all great I think, just try. You can cook for 10-15 minutes too, but I think you'd extract less from the same amount of beans. Mixing the water will extract faster. Keep it closed so it doesn't get too much air during long cook, the less it oxygenizes the fresher is tastes I think. A well-covered pot with just a small whole for water vapor is good.
- Otherwise when I can't stay home to cook it, I just put the ground coffee in a thermos and fill it up with water about 80-90'celsius and seal it, so the heat is preserved, and it gets "cooked" for a couple of hours and then I drink it. Usually I shake it every few minutes to get it to extract better.
- I think it stays very fresh for a few hours in a sealed thermos (don't let it touch air too much).
On the web some people suggest to soak the beans for 12 hours before cooking.
It’s more complicated to do I think. Depending on the original processing these beans had (wet or dry process), they might get too fermented. I only tried it once, and it was too fermented for my taste.
But if you have the time, I’d recommend trying it, my guess if done well it could be very nice, like sprouted legumes.