Almost as soon as tickets for the BottleRock Napa Valley went on sale Jan. 7, David Graham popped the wine corks in victory.

“We realized that we would be selling the show out during the first day of the ‘on-sale,’” Graham said Thursday with the announcement earlier this week that the May 27-29 music festival was sold out.

Though no attendance figures were given, roughly 40,000 humans a day are expected to the event that features headliners Stevie Wonder, Red Hot Chili Peppers, and Florence + The Machine.

“The biggest surprise has been the demand for VIP passes, which went really fast,” said Graham, one third of the production team at Latitude 38 Entertainment.

“When we did a survey after our 2015 festival, one of the questions went specifically to VIP pass holders asking if they would be buying a VIP pass for the 2016 BottleRock festival.”

Some 96 percent responded affirmatively, “which is a fairly unheard of percentage in the festival world,” Graham said.

Despite no longer fretting about peddling tickets, Graham said it doesn’t change BottleRock’s marketing strategy.

“It really doesn’t,” he said. “We are going to continue to put together a robust marketing plan with a robust marketing budget. We are taking nothing for granted.”

Not that Graham isn’t tickled at the festival’s apparent popularity that complements the headliners with about 60 other bands plus a culinary-celebrity experience.

“It means that there is demand for the kind of festival/customer experience that we offer, which is very different than what is offered at other music festivals,” he said. “It also means that we have tapped into a new festival customer — one that very much appreciates experiencing everything that the Napa Valley has to offer but within a music festival.”

It also means, continued Graham, “that you can book a lineup that is very attracting to a 20-something customer but still very approachable to those in the 40s or older. Mostly, it means that we need to stick with what we are doing while realizing that we also need to continue to make huge improvements to our festival every year like we have been doing.”

Securing the early sell-out and proving the event’s popularity gives the producers more leverage in snagging high-profile sponsors, Graham said.

“It provides an opportunity to continue to be even more selective about who we work with,” he said.