He is the fourth-generation Long about the business, a pedestal fan his only advertising; he switches it on at strategic moments, when he's grating another root - "I grate them, I don't grind them" - sending a sharp mist over the aisle. "The weeping fan," he calls it.
He carries a few spin-offs - a zingy barbecue sauce he has been working on, a tangy cocktail sauce he supplies to local seafood and grocery stores, a hot mustard, and what his wife, Cynthia, calls his "sneak-attack pickles," chilled, crisp, sweet spears from which the hit of horseradish does not emerge until you're a few chomps into them.
Regulars bring their empties back. Little girls drag their mothers over for his lemonade. Tourists flinch when Long stuffs another knobby root in the mouth of the grater - and the fan spreads the news.
It is not a business at a glance that has "high-end speciality food brand" written all over it, or "international potential" (although Balducci's, the New York-based gourmet food chain, does carry Long's in a private-label jar).
But a funny thing happened a year ago, even as Long, boyish at 57, was himself musing about incremental expansion. Say, a Web site maybe. Or Internet ordering. Or maybe he could get the guy who runs the Italian deli stall down the aisle to take a few cases to the Reading Terminal Market when he went to Philadelphia to pick up his cheese and olives.
Long's tech-savvy son, Andrew, 29, submitted the family business (established in 1901 by Long's German great-grandfather, then Lang) as the test case in a student contest run by the One Club, an advertising-industry group. It was chosen. The challenge? "Reposition Long's Horseradish as a high-end specialty brand."