For pre-roasted whole beans use this method.
Keep your whole beans in the freezer, along with your grinder for a least a few hours prior to grinding. Both the beans and the blades will be cold, wont overheat yo beans.
I have both a roaster and a grinder so I dont need to use this method anymore. I buy unroasted beans in 20 to 30lb burlap bags which stay fresh for up to 2 years without need for refrigeration. But as soon as you cook the bean everything changes and you have to be real careful with them to preserve their flavor.