Some dark liquors can actually protect the stomach lining. While some congeners can cause sensitivity to consumers, others can have a protective effect. It has been discovered that butanol, found in whiskey, has a protective function for the stomach lining. 

Thanks to congeners, dark liquor is more likely to cause a hang-over. There are good and “not so good” congeners. Light liquor is much less likely to cause hang overs. Drinking plenty of water throughout your night can combat hang overs all together.

Clear liquor has fewer allergens. Impurities are created when fermenting liquor and attribute to the taste and flavor. Therefore, high-quality, clear liquor has little taste. Clear liquors have never been fermented.

This fact goes for all alcohol but is still very interesting. No alcoholic beverage can be over roughly 190% proof or (95% ABV). At a higher proof, the liquor will self-dilute by drawing moisture from the air.