Rye whiskey used to be the most popular brown spirit in the United States before Prohibition began in 1919. Rye whiskey is one of three straight American whiskey styles, the other two being Tennessee and Bourbon. With straight whiskey, 51% of the spirit must be made of grain, the spirit must not exceed 160-proof, must be aged for at least two years and can only be diluted with water to no less than 80-proof.

There are two types of rye: American rye whiskey and Canadian rye whiskey. With American rye whiskey, the spirit must be made with at least 51% rye. With Canadian rye whiskey, there is no law that requires how much rye must be used to make the spirit. Wheat and malted barley are other ingredients that are used in making rye.

American rye whiskey must not exceed 160-proof. Before the rye is barreled in a charred, new oak cask for aging, the spirit cannot be any higher than 125-proof. In order for a rye to be considered “straight”, the spirit must be aged for at least two years.

Rye whiskey has a similar taste to bourbon. Rye is generally spicier than bourbon and tends to have a bitter taste due to the main ingredient being rye. With corn as the main ingredient, bourbon tends to have a sweeter taste and have a slightly more heavy body than rye.

Old Overholt is the only straight rye whiskey that survived Prohibition and is still in production and available on the market today. Rye whiskey is slowly coming back into fashion due to producers putting products out on the market such as Old Potrero by the Anchor Distilling Company here in San Francisco and (ri)1 Whiskey produced by Beam Global.

Sources:
http://www.examiner.com/x-6861-Bartender-Examiner~y2009m9d2-Bartending-101-What-is-rye-whiskey
Rye Whiskey-Wikipedia, the free encyclopedia
Mr. Boston’s Platinum Edition
http://www.examiner.com