Maker's Mark are very fussy about their water, and source it only from a 10-acre limestone spring-fed lake at the distillery. Maker's Mark are equally choosy about selecting the grains that go into the Maker's Mark whisky. Yellow corn and red winter wheat from specially selected small farm cooperatives, all of which are located within the limestone geology near the distillery, gives Maker's Mark whisky its soft, mellow taste. Maker's Mark is currently the only operating bourbon distillery to make whisky in batches of less than 19 barrels -- the traditional standard for small-batch whisky.
Maker's Mark only use naturally malted barley, and when grain is delivered, if it does not meet rigid standards the shipment is not accepted. And this really does happen from time to time. Maker's Mark use an old fashioned rollermill to prepare grain for cooking. While some distillers think this method is too slow and produces a lower yield, the slow process does not scorch the grain like a hammermill can. Scorching may result in a slightly bitter taste. By using an open cooker and a slower process that involves a lot of hands-on attention, Maker's Mark extend the subtle grain flavors into their whisky. Maker's Mark are among the few remaining bourbon distillers that propagates its own yeast for fermentation with cultures that can be traced back to the pre-prohibition era. Maker's Mark also use the traditional sour mash method, similar to making sourdough bread, where culture from one batch is used to start another. Rare cypress fermentation tanks are historically irreplaceable. Some of the planks are more than 100 years old.
Maker's Mark double distills its whisky -- once in an all copper column still to produce what is called low wine, and again in a copper pot still to produce high wine. This added step removes impurities and produces a more refined sipping whisky. Maker's Mark low wine is distilled off at 120 proof, while our high wine is 130 proof. Maker's Mark believe that this is the lowest distillation proof in the industry, and continue this more expensive practice because it preserves mellow grain characteristics.