What is Hard seltzer?

Hard seltzer, adult seltzer, mature seltzer, spiked seltzer and hard sparkling alcohol water is a type of highball drink containing seltzer , alcohol, and often fruit flavorings. In the US the alcohol is usually made by fermenting cane sugar; sometimes malted barley is used. Hard seltzer products outside of the US have been found to use either neutral spirit, or fermentation of fruit. The alcohol by volume is around 5% and the calorie-content is relatively low.