A brown-haired man in a black Boulevard Brewing Co. fleece jacket, Witte turns right when the tunnel reaches a fork. (Left would take him to Arrowhead Stadium, according to a pair of arrows painted on the white concrete-block wall.) Boulevard's field quality manager passes pallets of buns and sodas on his way to the three rooms beneath the stadium for vendors. He's here to train six people on how to fill and use the new Boulevard beer backpacks debuting today. The gear is part of a recently announced partnership between the hometown brewery and the Royals that also includes two Boulevard-branded grills and a pub behind home plate.
"I'm excited to have the backpacks back at the K," Witte says. "People will be able to get draft beer in the stands, and I think that's pretty cool."
This isn't Boulevard's first try at creating a mobile tap.
The then-fledgling brewery tested a backpack at the stadium during the 1994 season. But those early attempts held nonstandard kegs that couldn't be filled on the bottling line. The concept needed work, and the task fell to Witte, who has been with Boulevard since 1997. He went through dozens of prototypes in his workshop, just off Front Street, to figure out how to protect the beer from Kansas City's blazing summer heat.
This backpack has been field-tested - it's been borrowed for employee camping trips, the occasional barbecue, and Sporting KC's games since St. Patrick's Day. (A pair of backpacks are at Livestrong Sporting Park all season.) Witte even dropped a few hints on Twitter about the idea, to test the public's reaction.
"Guys wrote back saying, 'Man, I wish I could have that when I'm mowing the lawn,'" Witte says. "I'm thinking, It's hard enough to mow my lawn without 50 pounds on my back." But if it's a bit heavy for leisure use, it's in line with what vendors typically must heft during a game. "It's not any heavier than a backpack on a backpacking trip," Witte says. "And it's just going to get lighter."
A little more than three hours before the season opener against the Cleveland Indians, the stadium's vendors have reported for roll call. They're downing plates of Swedish meatballs and Salisbury steak, waiting to find out what they're going to sell. Their payloads depend on seniority. To Witte's delight, the backpacks are in high demand among the veterans.
"I thought I was going to be a Boulevard man," says one vendor, fingering a white badge that reads: "Peanuts."
The six assigned to sell Boulevard Wheat get sorted out, and Witte begins the training. He speaks slowly - his delivery has been honed during the regular workshops he holds on beer-delivery systems for distributors and retailers - and watches the vendors' hands as much as their eyes to make sure they're getting the concept.
"I've never seen beer like this," says Aramark's Bob Kimsey as the first beer is poured. 'I've seen hot chocolate but never beer."
The backpack was, in fact, designed to dispense hot chocolate. Witte modified an existing product to account for warmer temperatures and to keep the beer flowing consistently. Among the retrofits, Witte has added an insulated line and a regulator to control carbon-dioxide pressure. Cold beer means less foam. When the vendors handle money, they can place the dispensing faucet on a small hook by their belts. A cupholder is snapped to the side of the backpack.
He shows two of the vendors how to tap the 3.3-gallon keg, which holds enough to serve 26 16-ounce beers. The backpacks wait at the end of a long stainless-steel prep table. Nearby, cases of Coors Light and Leinenkugel Summer Shandy sit under ice inside black carrying tubs. A mana-ger estimates that the tubs - the standard for beer vendors - weigh at least 45 pounds.
"I've worked in a lot of bars and drank a lot of beer. I can handle this," says Jason Cherry, a vendor for the past 11 years at Kauffman.
Witte gives a quick lesson on how to pour, tipping the cup at a 45-degree angle under the faucet.
"Good beer should have a little bit of head," Kimsey reminds his staff. "Now, put on your proton packs and head out there."
Cherry puts the straps around his shoulders and gets ready to walk the steps at Kauffman. The gray clouds have lifted for now, and the sun looks ready to shine on the first pitch. "It's Opening Day," he says. "And there's nothing like Opening Day."