Heather Showman, who started serving at the RH last summer and who grew up in Columbia, S.C., was very happy to see it on the specials list when we first started doing it. I can't remember how it came up exactly but one day she said, "I think I was 15 before I realized barbecue could come in any color other than yellow." I still smile every time I think about her saying this--it really does get across the regionality of barbecue in the South and is a good reminder of how much each of us takes our own "normal" for granted (usually incorrectly) as the "way things are everywhere."
With all that in mind, South Carolina is seemingly the most diverse of barbecue states (though I'm sure someone out there's going to argue this one so...). If you go to the Carolina Q Cup Website, at the bottom of the page you'll find a nice little colored map showing where the various styles are still found in the state. Mustard, like I said, is mainly in the middle. In the northeastern part of the state they seem to eat mostly vinegar sauce akin to the Eastern North Carolina style we already do. In the northwest it's tomato vinegar akin to the way it's done in western North Carolina. In the south down by the Georgia border they opt for a thicker tomato-ketchup type sauce.
No one seems very sure of the mustard sauce's actual origins--one theory I saw said that it could have been tied to the settlement of a fair few Germans in the area and their love of good mustard. Germans were actually actively recruited to the South Carolina colony in the first part of the 18th century, and there's a relatively strong community still there. Some of the biggest names in South Carolina mustard barbecue are of German origin--Bessinger, Sweatman, etc. John T. Edge pointed out that there are also pockets of mustard sauce served in Georgia and Alabama as well.
The main thing here is that the mustard sauce is really good. Nothin' fancy--a lot of yellow mustard, a good dose of the Quebec, oak-barrel aged cider vinegar, a touch of sugar, and a bunch of spices (ground coriander, celery seed, fresh garlic, chili pequin, and fresh ground Telicherry black pepper). As you can tell, I like it, and I like being able to teach people about the little ins and outs of food and food history (in case you didn't notice that about me).
While it's good on a dinner plate, I'm particularly partial to it on the sandwich. Those New Jersey buns from the Bakehouse are just so good--actually one of our more unknown items, I think. Be sure to put the slaw on the sandwich as they would in the South--I think it adds a lot to the textural enjoyment! If you're up for a little BBQ adventure, check it out.