Do not drink orange juice with creatine, or any type of acidic drink. Creatine is extremely volatile and the acid in the drinks will destroy the creatine. This is why you need grape juice or some other type of simple sugar carrier to get that creatine out of your stomach and into your blood stream as soon as possible before your stomach acid breaks it down.
Creatine is tasteless, and odourless. If you're having a problem with the grittyness of creatine, mix it into a little bit of water first till it disolves, then add grape juice.
The other thing you can do (my preference) is to just put the 5mg on my tongue, then chase it down with grape juice. Quick, simple, and effective. :)
justin