Boil the root beer in an 8-quart saucepot over high heat until reduced by half, about 15 minutes.
Lower the heat to a medium-low and add the ketchup, brown sugar, cider vinegar, pepper, ground ginger and salt. Simmer, stirring frequently, until the sauce reaches the desired thickness, another 5 to 10 minutes.
Chill in the refrigerator until fully cooled.
Reduce the sauce to your desired thickness, but understand that the more you reduce the sauce, the more intense the flavor will be.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.