Okay guys, I did all the hard work for you. All you have to do is find a birch tree, kick a chunk off and start from there. Simple as that is, I'm making it even simpler! :)
So you got the stuff off the tree. Good for you. Letting it sit for a while in the sun (by a window or something is a great idea since there is moisture built up in the chaga. When you plunk and chunk and store it in a zip-lock, you'll wanna avoid any musty qualities which could conjure. Your chunk(s) can also be stored in the freezer immediately if you want to avoid the drying process.
What I have here is an extra crispy dry piece of chaga in a large freezer zip-lock bag.
I've taken a small chunk that you can see outside the bag to crunch in a mortar and pestle.
Place the grinds into a small slow cooker with water. This amount will make a very dark coffee colour.
Let it sit for 8 hours or so.
Presto! I told you -- dark black coffee colour. I brew the same batch of grinds again to get almost the same depth of colour.
This is basically it. I used a mortal and pestle, although it is possible to use a espresso grinder. My experience is that the espresso grinders go through a lot of hell and you have to do some DIY to fix em up again after the blade loosens up. Some parts of the chaga when ground are as hard as wood. The espresso grinders are easy to find for $5 from a second hand store. The mortar and pestle is unbreakable. The 3rd option I have yet to try is a meat grinder (hand crank) thing. Apparently they work just fine. If you want a espresso grind (which the meat grinder will not provide) it you can go another step with a hand cranked espresso grinder to build those muscles. If you don't have a slow cooker, you can always the stove-top with a pot. But slow cookers are twice as easy to find then even a espresso grinder in a second hand store.
Now I must be honest here. The brew is not all that bad at all! I can easily take it straight with nothing added, but to impress yourself, add whatever you'd like. Put it in your favorite juice container! Add root beer concentrate mixture... your favorite fruit tea mix in the slow cooker, rooibus? Yes, all those work quite well. Be creative - I trust you. Don't blame me if something blows up. I should add though that like most fresh teas, you would stick the mixture in the fridge for no longer then 2 weeks.
Why would you want to do this? This is one of the simplest YouTube videos to explain it. You can always refer to one of my old blog pages on chaga as well which spell out the benefits.