Alcoholometer is a special type of hydrometer which is used for determining the alcoholic strength of liquids. A hydrometer is an instrument used to measure the Specific gravity (or Relative density) of Liquids that is the ratio In Chemistry, an alcohol is any Organic compound in which a Hydroxyl group ( - O[[hydrogen H]]) is bound to a Carbon Such type of hydrometers have special scale marked by volume percents of an alcohol in water. It is used by brewers of alcoholic beverages to determine the alcoholic content of the beverage.