Samantha Ku A selection of flavored seltzers at Northern Spy Food Co., 511 E. 12th St.

Instead of biting into a crisp apple to celebrate (finally) the start of fall, how about going upscale with a glass of homemade Fuji apple lemon seltzer? Or you could try Concord grape or quince, all flavors concocted for microbrewed seltzer.

Northern Spy Food Co. at 511 East 12th Street between Avenues A and B has been serving the sparkling spritzers since opening November. The flavors, made from locally sourced, organic ingredients, change with the seasons from strawberry-rhubarb in spring, to cucumber-mint for early summer, and watermelon-basil for the early days of autumn.

The restaurant, named after a local variety of apple, even mounted an old-fashioned seltzer arm, hearkening back to the soda fountain heyday of the ‘20s and ‘30s.

Samantha Ku Preparing a seltzer with carbonated water and syrup.

Traditional soda fountain culture has its roots in the natural mineral baths of 18th-century Europe, according to Anne Cooper Funderburg, who wrote “Sundae Best: A History of Soda Fountains.” Scientists believed that duplicating the effervescence of the spa waters would also produce healing effects in the body, a far cry from soft drinks of today. Now, restaurateurs are taking fountain drinks back to their roots with fresh ingredients and simple flavors.

Samantha Ku Northern Spy Food Co. owner Chris Ronis enjoys his creation, the coffee seltzer.