Jack Daniels is not Bourbon because it is filtered though granules of carbon before barreling. Some Bourbons are filtered, after aging and before bottling. The effect of adding flavour through the filtration is apparently what makes it not Bourbon which disallows any flavour or colouring added or imparted.

Many Bourbons are in fact sour mash, all which that means the mash from a last batch is added to the new batch. Akin to starter for sourdough always being used in the next batch for generations. It doesn't really matter as it is not really very good and there are better real Bourbons available in the same price range.

Notwithstanding its averageness, if you are near Nashville (used to be a great AA hub ex-YYZ) a side trip to Lynchburg for the tour is worth it. No samples. It's a dry county but they don't give samples to to other regulations and hassle. Apparently they could give samples under county law if they wanted to. They give you very nice lemonade.