Prohibition had a huge effect on the taste of the product that we call bourbon today. For 13 years people had to drink products that were distilled before 1918 (War time prohibition stopped production of beverage alcohol that year and was never repealed before national prohibition took effect). This meant the legal "medicinal alcohol" was often to old and woody by the time the consumer purchased it. The good illegal products were often cut with grain neutral spirits or water. The best spirits that could be purchased were imports from Canada or Scotland, smuggled in and expensive.
When prohibition was repealed the industry had decided that the consumer wanted a lighter product, because the "good stuff" that they were used to drinking was all lighter in flavor. This led to higher distillation proof and eventually higher barrel proof.
Another change was the regulation and definitions that were standardized after prohibition. The biggest change here is the use of only new, charred oak barrels. Every straight bourbon or rye made after 1 March 1938 had to be placed in a new charred oak barrel. It was common practice before this time to reuse some of the barrels even though the majority of the product was placed in new charred oak barrels. Remember, before prohibition there was a big market for whiskey by the barrel and you could still purchase the product straight from the barrel at your local saloon or drugstore. This meant that most empty barrels were in the hands of the consumer, not the distillery. This meant that many people were drinking single barrel, unfiltered, barrel proof product before prohibition.
Prohibition changed the way America drank its bourbon and the bourbon that they drank. I just hought it was interesting that the products that consumers consider top notch and are willing to pay the extra money for are the same products that the industry decided after prohibition, people did not want.
Mike Veach