The mystery starts inside the Washington Capitals’ locker room following each practice or game with forward Jay Beagle clutching a plastic bottle of pink liquid. In the crammed NHL schedule, stuffed with back-to-backs such as this weekend’s matinees against the New York Islanders and Philadelphia Flyers, the recovery process begins for Beagle, sometimes mid-interview, by shaking the bottle hard, blending the drink and gulping it down.

As a teenager, Beagle, 29, learned the importance of recovery from a personal trainer who advised him to put nutrients into his body within 15 minutes following workouts. So Beagle began mixing his own shakes. He once made regular batches for teammates, until some mischievous types started stealing his frozen blueberries and his grocery bills soared. And with the same unrelenting intensity seen from him each shift, a stamina at least partially fueled by this attention to nutrition, he refuses to divulge the recipe.

“I can’t tell you,” Beagle said. “I’ve given you so many of my secrets, now if you write about it, everyone’s going to know, and now I’m not going to have the competitive advantage.”

The already divulged “secrets”: Before games, he likes eating sweet potatoes, chicken and vegetables, sometimes with gluten-free pasta. After games, he trends toward more carbs and “good fats,” such as avocado. On off-days, he tries a 45-minute walk with his wife, newborn son and dog. With another puck drop rapidly approaching, Beagle knows his caloric intake and activity patterns will affect how he sleeps, how he feels upon waking and, most importantly, how he plays.

“Throughout my career now, it’s gone from maybe three or four people doing it, to almost everyone on the team doing it, which is good,” Beagle said. “You want your whole team doing it, with the way the schedule is, with the back-to-backs and everything, the recovery’s huge.”

But everything starts with the shake, which Beagle said contains a four-to-one carbohydrate-to-protein ratio, guzzled down quickly after strenuous activity, because as strength and conditioning coach Mark Nemish said, “There’s a window in which we want to replenish the glycogen and repair some of the protein that might have been damaged on the ice through starting and stopping, the bumps and bruises of the game.”

At Kettler Capitals Iceplex and Verizon Center, Beagle uses a Nutribullet, a hand-held blender belonging to the team masseuse. On the road, he packs a personal “shake bag” with supplements and ingredients that the equipment managers carry with everything else. He protects the exact recipe from teammates, too.

“I’m going to guess, just a little bit of red food coloring, shake it up, make it look good,” forward Troy Brouwer said.

“I don’t know,” defenseman Karl Alzner said. “Ice and water. And hard work. He just fills it full of hard work.”

“It’s junk,” defenseman Brooks Orpik said. “Sugar. Just boatloads of sugar. You can tell him I said that, too. It’s junk, what he puts in there. He’s got his own stuff. I don’t know. Whatever works.”

Unlike Beagle, Orpik learned about proper recovery methods as he grew older. Now in his 12th season, Orpik uses foam-rollers after games to stretch and recently purchased a RecoveryPump, effectively compression therapy pants that stimulates blood flow. Recently, on a one-game road trip to Ottawa, Orpik conducted his postgame interview while digging into a Tupperware of rice, chicken and broccoli, packed for the ride.

Orpik also shuns the cold tub, Nemish’s most recommended form of recovery, because of how fast it reduces the amount of heat being generated in the legs and the body, but admits that his personal habits have evolved with time, and everyone treats their body in different ways.

“I think for me, sleep and nutrition are probably the biggest thing for recovery,” Orpik said. “That’s something you learn as you go. You probably get away with some more things when you’re younger.”

Others, such as Alzner, prefer a more relaxed approach. The compression pants and protein shakes and cold tubs are endeavors better suited for summer, he said. Averaging more than 19 minutes of high-intensity skating each night, riding an iron-man streak of zero missed games over the past five seasons, Alzner, 26, envisioned one day needing to cut down on junk food and ratchet up the recovery protocol. Just, not now.

“I lay on the couch as much as I can and not move,” he said. “That’s pretty much it. During the season I just try to let my body be happy and take care of it by resting.”

Every player, though, preached the importance of immediate hydration, and since Beagle once shared his shakes with Alzner, the latter became a pivotal target for unraveling the mystery. The drink Beagle made last season, Alzner recalled, contained blueberries, protein powder, bananas, one scoop of almond butter, water and ice. This list was brought back to Beagle for confirmation.

“That’s the closest,” Beagle said. “He’s missing probably about seven ingredients. So not that close. But it’s a start.”

Across the locker room, defenseman Jack Hillen overheard the conversation, one of several that ended in stonewalling.

“Is he still asking about supplements?” Hillen said. “Oh my god. Get over it.”

“You’ll never figure it out,” Beagle said.

“You’ll never know,” Hillen said.