A bartender's assistant, working in nightclubs, bars, restaurants and catering halls. Barbacks stock the bar with liquor, ice, glassware, beer, garnishes, and so on, and usually receive a portion of the bartender's tips; often around 10% to 20%, or a portion of total sales; from 1. 5% to 3%. At high volume bars, this may then be divided if more than one barback was on staff.