Corn on the cob needs to be blanched before freezing because blanching slows down enzymes that destroy the flavor, texture and color of the corn. Blanching corn before freezing also helps remove dirt from the corn and brighten its color.
Corn on the cob is frozen in the same manner as corn off the cob. However, the blanching process takes a few minutes longer for corn on the cob. Small ears of corn should be boiled for 7 minutes, medium ears for 9 minutes and large ears of corn should be boiled for 11 minutes. Corn should be cooled for the same amount of time that it is boiled.