Carefully peel the husks of the corn down to the bottom of each ear without detaching. Remove and discard the silks. Gently rinse the corn. Carefully fold husks back around ears. Tie husks tops with 100-percent-cotton kitchen string to secure.
In a very large bowl or tub, combine cold water and salt; stirring until salt mostly dissolves. Place corn in the water (all ears need to be covered). Put a pan on top of corn to keep ears submerged for 1 hour before grilling. Drain corn; pat dry.
Grill corn on the rack of a covered grill directly over medium coals for 25 to 30 minutes, turning and rearranging with long handled tongs three times, until kernels are tender.
To serve, remove string from corn; discard. Peel back husks. Serve with Cumin Lime Butter. Makes 6 sevings.
In a small cast-iron or heavy skillet, cook and stir cumin seeds over low heat 1 minute. Add coarse salt and ground chipotle chile pepper. Cook and stir for 1 minute more or until seeds become fragrant and lightly colored. Remove from heat; shake skillet for 1 minute. In a spice or coffee grinder, place cumin mixture. Cover and pulse until ground. In a small bowl, stir together butter, cumin mixture and finely shredded lime peel. (Store any remaining butter in tightly covered container in refrigerator for up to 3 days.) Make about 1 cup.