Sour mash is simply that which is made from left over yeasts that have - soured.

Sweet is done with fresh yeasts.

You can not make bourbon or good corn liquor if you live in a place where there any iron in the water.
Having no iron in the water was great for Whiskey making in the south but it made it hard to find enough iron to make gun parts in the civil war.

Scotch also is entirely dependant on the water composition.

Distilled water is dead and useless for whiskey. You need the right water.

The color - most of it comes from aging in oak barrels that were prior used for various kinds of grape products.

50 pounds of the grain of choice
200 lb sugar pure powdered corn sugar -- no syrups, no cane sugar
200 gallons water
16 oz yeast

Grind then Pasteurize the grain in the water when cool enough to add the sugar and yeast add 'em and mix well.
Go pet the dog for a while.
when the bubbling stops you can distill it.

Whiskies need lots of aging in nice expensive oak barrels. Vodka and gin don't.