Every dwarf's best friend! Brewers brew various plants into alcoholic beverages, such as ale, beer, and other spirits. Since all dwarves need alcohol to get through the workday, this is a very important skill.
Regardless of skill, a brewer produces five units of alcohol for each unit of brewable plant. Because of crop stacking, this allows brewers to synergize well with highly talented herbalists and growers (who are more likely to produce larger plant stacks), and can quickly lead to cluttered stills. A brewer will turn "Plump Helmet" into "Dwarven Wine ", and will turn "Plump Helmet " into "Dwarven Wine ." Both actions fill one empty barrel (despite their different quantities), and presumably take the same amount of time to brew.
As brewers become more skilled, they work faster. Although alcohol has no listed item quality, it is also presumed that brewer skill level creates a hidden quality level for alcohol, since dwarven thoughts and preferences often mention high-quality drinks.