To grill corn on the cob wrapped in foil, the typical cooking time is about 15 to 20 minutes over medium heat (around 350°F to 400°F). You should turn the foil-wrapped corn occasionally during grilling to ensure even cooking. The corn is done when the kernels are tender and slightly charred or browned in spots

. Here are some key details:

• Preheat your grill to medium heat (350°F-400°F).
• Wrap each ear of corn individually in foil, optionally with butter and seasoning inside.
• Place the foil packets on the grill and cook for about 15-20 minutes, turning every 5-10 minutes.
• For best results, remove the foil packets and let the corn rest for about 5 minutes to allow steaming inside the foil, which softens the kernels further

• Check doneness by piercing the kernels with a fork; they should be soft and juicy.

If cooking with husks on, grilling time may be longer (around 30 minutes), but with foil and no husks, 15-20 minutes is sufficient

. In summary, grill foil-wrapped corn for about 15-20 minutes over medium heat, turning occasionally, then let it steam briefly before serving