A reflux still is a type of distillation apparatus used to purify liquids, particularly in the production of alcoholic beverages like whiskey and vodka. It operates by heating a liquid mixture, causing it to vaporize. The vapor then rises through a column where it encounters cooler surfaces, allowing some components to condense and return to the mixture, while others continue to rise. This process enhances the separation of different substances based on their boiling points. The design of a reflux still often includes a reflux condenser, which cools the vapor and promotes the return of liquid back into the column. This setup allows for a more efficient and higher purity distillation compared to simpler stills. Reflux stills are commonly used in both commercial distilleries and home distillation setups, making them popular among enthusiasts of homebrewing and spirits production.