Had he tried, on this morning after, to come to work though the club's Broad Street doors, it might have caused a commotion. He was a walking violation of the letter and certainly the spirit of the club's rather starchy dress code - ribbed, zip-up sweater (non!), jeans (non!), hip black tennis shoes (non!).
But not to worry. He came through the more forgiving brass door on Sansom Street, clomped down a few steps and, in an instant, was in the vast kitchen, the steerage below decks.
His first impression when he saw it a few weeks ago was, "Whoa! It's old. It's big!"
The wooden cooler doors were as thick as a dungeon's, the butcher-block tables as worn as a South Philly rowhouse step. The club goes back 146 years (to 1862); the ring-burner in the pastry kitchen looks like it.
Hamann's hair is a steely stubble, his build is a linebacker's, his background, a baker's son from Morton ("like the salt"), Delaware County. He had no earthly idea what the Union League would be like. Never in his 50 years had he set foot in the place.
He spent his first days cleaning up the toll-booth-sized chef's office, repainting it with the help of a steward.
As a point of reference, he said, its kitchen could swallow up four of the Four Seasons' kitchens. There were 12 walk-ins here. There were only four at the hotel where he was mentored by the legendary Jean Marie Lacroix ("my 'dad' ") before succeeding him as head chef in 2001.
At the hotel they could put out 450 meals a night, French service, which means a waiter serves the starch, vegetables and meat from a silver tray, as a second comes behind him, saucing the food. At the club, next week alone - with banquets for groups such as the Development Corp. of Israel and the Parkinson's Council - the kitchen would need to deliver 500 and 600 meals a night, already plated.