For an even roasting of the beets, fold the foil over them and crimp the sides closed. This helps keep them moist, it also helps contain the powerfully staining juices they'll emit while roasting and make clean-up a snap.
Roast beets until tender. The amount of time this will take can vary greatly depending on the size of the beets, how many there are, if other things are in the oven, and how fresh the beets are (fresher beets cook up faster). For smaller beets, start checking them for tenderness at about 25 minutes. Larger and older beets can take up to an hour.
