SAN DIEGO — On the top shelf of Chris Heisey’s Nationals Park locker, which is filled with all the usual baseball accoutrements, sits a sleek silver cylinder, too shiny and smooth for this world of dirt and dust and daily grime. Nearby, one usually finds a bag of specialty coffee beans, dropped off by a teammate or picked up from an intriguing little coffee shop in an unfamiliar city. Those beans do not usually last very long.

Heisey, who made the roster out of spring training and has contributed pinch-hit homers and glue for the clubhouse since, has become the unofficial master of the French press, and many of his teammates are hooked. Stephen Drew bought one, too, when what Heisey’s could produce was just not enough.

“Some guys don’t drink coffee. I don’t think they’re non-believers; they just don’t like the taste of coffee,” Heisey said. “But most guys try it. Now, they’ll yell at me, ‘Where’s the French press?’ I say, ‘All right, guys, I’ll get it.'”

The story of how a French press made its way into the realm of Gatorade coolers began last fall, after Heisey spent most of the 2015 season in Class AAA: with Buffalo in the Blue Jays’ organization, and Oklahoma City in the Dodgers’. He and his family took his mother to a lake house for her 60th birthday, and his sister brought a French press along.

“I was like, man, this is the best coffee I’ve ever tasted,” Heisey said. “She bought me a French press. All winter, I made a French press pretty much every morning.”

Heisey arrived in spring training as a non-roster invitee, having played for Manager Dusty Baker in Cincinnati. He befriended fellow non-roster invite Reed Johnson, the gregarious veteran outfielder who was one of the last players cut — one of Baker’s hardest cuts, he said later. They were talking in the outfield during stretching one day when it came up.

“He was like, ‘Dude, we gotta get one for the clubhouse,’ ” Heisey said. “So he and I went to Target and bought a French press and a coffee grinder.”

They kept it at Johnson’s house, where they met every morning to make coffee before workouts began. When the season began, Heisey decided he needed one in the clubhouse, so he brought it in.

“I think the first couple nights that I took it out for the game on the bench, we won,” Heisey said. “I know I was giving Dusty a cup, and then one day I forgot. He was like, ‘Dude! Where was my coffee today!?’ It was kind of like, ‘Man, we need the French press!’ I feel like instead of taking energy drinks, they just drink coffee before the game.”

He and Drew are the unofficial supervisors of the French press production. Drew got involved when he tired of running back and forth to the single-cup coffee maker in the clubhouse. When Heisey’s press was not providing enough coffee for all those consuming it, Drew bought a bigger one.

“We don’t put anything in it. It’s just straight black,” Drew said. “Everybody started getting it. It really is a taste. Once you get used to it, you don’t want anything else.”

Heisey estimates that the Nationals have tried 15 or more different types of beans. Jonathan Papelbon, another strong proponent of the French-press coffee, ordered a bunch of beans online and had them shipped to U.S. Cellular Field when the Nationals were there earlier this month.

At one point he stopped Danny Espinosa as he reached for a normal coffee pot. Papelbon handed him a green styrofoam Gatorade cup and poured out what was left in the French press.

“You think their coffee is stronger than normal coffee?” Espinosa asked Anthony Rendon, repeating a question he had just been asked. Rendon was one of those who hadn’t tried it.

“Stronger-tasting,” Espinosa decided, without a second opinion. “I don’t know about caffeine. It’s a bolder roast. It’s really good.”

That same day, a few minutes after Espinosa chose the French press, Clint Robinson opted for the normal coffee pot.

“Too bitter,” Robinson said. “I couldn’t get it down.”

The French press coffee, it seems, is an acquired taste. Thanks to two of their most productive contributors off the bench, though, these Nationals have acquired it — and with it, though perhaps not related to it, a firm hold on first place in the National League East.