I use white corn. The variety I use is "truckers favorite". It's good for "corn on the cob", for "creaming" and when it dry's for homemade cornmeal, and ofcourse cracking (corse grind) and making oldtime pure corn whiskey. If you don't have a corn sheller forget it, dryed white corn is tougher'n woodpecker lips. It keeps good on the stalk, I plant 5 or 6 akers and use out of it from one year to the next, feed the deer and the ducks with it too. Rabbits get their share also, then I get my share of rabbits. Take the bush hog and knock some of it down and shoot doves over it. As for the sugar in the corn I don't know, those people that use storebought yellow cracked corn and sugar get more whiskey from a barrel of mash than i do. (I use storebought & sugar myself sometimes)
Shelling corn and then grinding (by hand) is work.
To make good drinking whiskey from white corn I use two barrels. In the first one I put 50 lb storebought cracked corn and 50 lb white sugar then put in all the hot backset from the still (20 gal) put the lid on and let it set till the next day, then finish filling the barrel with good well water. Next day add three packes Red Star yeast (that's all my store carries) and a few drops of beano. Two days later put your cracked white corn in the second barrel, now dip all the liquid you can from the first barrel ( It'll be working real good) and put it in the second (white corn) barrel. Now fill the first barrel with well water again. When the second barrel starts working put in a few drops of Beano. IN 6 to 9 days they'll both quit working. Now distill'em, I use a reflux still and I aim for my middle cut to come off at bout 160 to 170 proof, I do this by adjusting the amount of copper mesch i have in my colum and leaving everything else the same from one run to the next. Now take your middle cut from the white corn whiskey and cut it 50/50 with good well water. Set this whiskey aside to age. I like to age mine in a glass jug with a corn cob stopper anyplace where its dark and don't get rained on, long as it's outside. As for the rest of the run and your yellow corn whiskey, just mix it all togather, that everday whiskey. That stuff out behind the barn, covered with leaves and an old piece of tin on it, why that your good sunday whiskey.