A couple of things.
First, the TV show is entirely, 100%, absolutely and completely fake.
Second, you can't make alcohol out of 100% corn and nothing else. The starches in the corn won't convert to sugar in the mashing process and so your fermentation will be unsuccessful. You need some form of catalytic enzyme. In a pure grain process, this comes from the malted barley. If you don't want any other grains in your mash then you have to use an enzyme additive such as amylase.
At any rate, my point is simply that even moonshiners don't typically deal in 100% corn because it tastes like lawn clippings. It's really quite awful. And rye, while not quite as cheap as corn, is pretty close - especially when you consider that it's conversion rate (fermentable sugars by weight) is very high.
