Before the grains can be cooked they need to be milled and, prior to the widespread use of electricity, every distillery used water to operate their mills, which is another reason why you'll find a creek, stream or river near every distillery you visit. Running through Maker's Mark distillery is a small waterway that is reverently called Whiskey Creek. However, this is not the water source, it is only a channel built by the Samuels family to divert any floodwater that comes their way.
The grinding technique at Maker's Mark is another diversion from standard operating procedure among distilleries. When the hammer press was invented distillers were drawn to the efficient device that literally hammer the grain to a fine powder. That didn't do it for Maker's Mark and Bill Samuels Jr. says it was a tough decision during which they consulted local bakeries. The bakeries denounced the new grinding technique because it added too much heat to the grain and that was one thing the Samuels had been avoiding at all costs. Instead of being super efficient, Maker's Mark decided to stick with the roller mill press which creates a ground grain of the perfect consistency and allows the sweet flavors of the wheat to shine through.