You probably shouldn't be boiling your apple juice, unless you know what you're doing.
I started a 1-gallon batch with a 2-inch "thumb" of fresh ginger, grated with a microplane grater. At 2 weeks, the ginger flavour is really strong, perhaps stronger than I wanted since it's hard to detect the apple. It's of course very young at this point and the yeast hasn't dropped so I'm not going to make any conclusions yet.
If you grate it, it will sink to the bottom and form a layer right above the yeast cake, which is going to be really annoying when you are siphoning or decanting. If I were to do it again, I would probably slice it into thin wafers like they suggest in this thread. It's also easier to do.
I didn't bother with sanitization and would worry even less if I put it in secondary.