MAULDIN, S.C. — The South has a penchant for odd loyalties, which goes a long way toward explaining why a man from North Carolina last year ordered a customized Duke’s mayonnaise jar in which to store his remains.

The Southern-made mayonnaise, a creamy spread rich with egg yolks and tart with cider vinegar, is so compelling that many Southerners would rather go without their beloved tomato sandwiches than eat one held together with Hellmann’s, the most popular mayonnaise in the world.

Of course, the same could be said about loyalists to Hellmann’s, a stiffer mayonnaise made with whole eggs and a touch of sugar, named after Richard Hellmann, a German who immigrated to New York in 1903, married the daughter of a deli owner and a decade later began selling bottled mayonnaise from the couple’s Columbus Avenue delicatessen.

America was in a mayonnaise boom then, with homey versions sold in the South and in other parts of the East Coast, including Philadelphia. By the mid-1920s, there may have been as many as 600 brands of commercial mayonnaise in America, according to the New York food historian Andrew F. Smith.