Johnny Harris Restaurant opened in Savannah, Georgia in 1924. That's a LONG time ago, especially in barbecue years. In fact, it's Savannah's oldest restaurant.
The signature barbecue sauce recipe was allegedly created by a black cook (their words) named John Moore in the early days of the restaurant. Johnny Harris eventually wrote the recipe down and passed it on to his business partner Red Donaldson. The sauce harkens back to a time before barbecue sauce was candy sweet.
This is a tomato-based sauce, but mustard is clearly the star of the show. In fact, it tastes more like a South Carolina mustard-based sauce than anything else. There is not very much sweetness to be found. The sauce is roughly the same color and consistency as Heinz 57 Sauce. The bottle has a message on the side in large print - "HEAT SAUCE TO DOUBLE FLAVOR".