Beer in the United States
On January 16, 1919, the Eighteenth Amendment to the United States Constitution was enacted into law, creating the Prohibition era, wherein the production, sale and transportation of alcoholic beverages was made illegal. All legal American brewing came to a halt when prohibition was imposed, though the earlier temperance movement had already reduced the number of breweries significantly. Only a few breweries, mainly the largest, were able to stay in business by manufacturing near beer, malt syrup, or other non-alcohol grain products, in addition to soft drinks such as colas and root beers. Production and shipping of alcohol was largely confined to illegal operations that could deliver compact distilled beverages—smuggled rum and domestic moonshine—more efficiently and reliably than bulkier products such as beer.
Bureau of Prohibition
The Bureau of Prohibition (or Prohibition Unit) was the federal law enforcement agency formed to enforce the National Prohibition Act of 1919, commonly known as the Volstead Act, which elaborated upon the 18th Amendment to the United States Constitution regarding the prohibition of the manufacture, sale, and transportation of alcoholic beverages. When it was first established in 1920, it was a unit of the Bureau of Internal Revenue. On April 1, 1927, it became an independent entity within the Department of the Treasury, changing its name from the Prohibition Unit to the Bureau of Prohibition. In 1930, it became part of the Department of Justice. By 1933, with the Repeal of Prohibition imminent, it was briefly absorbed into the FBI, or "Bureau of Investigation" as it was then called, and became the Bureau's "Alcohol Beverage Unit," though, for practical purposes it continued to operate as a separate agency. Very shortly after that, once Repeal became a reality, and the only federal laws regarding alcoholic beverages being their taxation, it was switched back to Treasury, where it was renamed the Alcohol Tax Unit.