Cook says the sessions with Grohl -- the result of meeting each other at this year's Grammy Awards -- "exceeded expectations" for the ZBB, which enjoyed immersing itself in the Foo Fighter's old-school studio aesthetic.
"We didn't really know what to expect," Cook says. "We just knew (Grohl) was kind of a cool guy. And we were just trying to break away from our normal fashion (of recording) a little bit. We felt a little bogged down and just wanted to see how he worked and kind of look behind the curtain at that land of Oz, pretty much.
"It opened up something in us that we were not tapping into before. It makes you work harder because you're (recording) to tape and there's no editing going on as far as in ProTools and computers and stuff like that, which is the way we were making records. You kind of play it about 90 percent well, and they can fix the other 10 percent of it and make it sound great. But you can't do that the way (Grohl) works, so it tapped into the real musicians in us. It was a little bit freeing to me. Some of the guys like to rely on (technology). There was a little bit of fighting, to be honest -- not actual fighting but having to demand more of each musician. But by the end of it everyone was happy and it put us in a great place."
It will be awhile before the ZBB is able to tap into those lessons in the studio again, however. With Brown and his wife expecting a baby this spring, the group is "trying to tour, tour, tour," with dates currently booked through March 26 and some summer festivals also on the docket. The ZBB will usher in 2014 in Detroit and also perform the national anthem at the NHL's Winter Classic game in Ann Arbor, and it plays a Super Bowl XLVIII show with Grohl and the Foo Fighters on Feb. 1 in New York.
"We've got enough songs to make a record tomorrow, but people like to see us play live, too, so there's no time to even get together and record between now and then," Cook says. "At some point we have to find the time and the right situation. You don't want to just go into the studio and try to bang it out as fast as you can. You want to make the best music you can possibly make. You don't want to rush it; I think people can tell if you're just trying to make money or if you really mean it. So you want a recording where you're trying to really make an awesome piece of art and try to touch people the right way. So it's basically 'Let's get all the way up to the baby and we'll start making decisions after that.'"
But, he adds, the ZBB may do something in the new year to commemorate the 10th anniversary of its self-released debut album, "Far From Einstyne."
"We've always been talking about putting out the old (pre-Atlantic Records) Zac Brown Band stuff, like 'Einstyne' and (2005's) 'Home Grown,' " Cook says. "We're still discussing what format to put it out. Do you re-release it? Do you try to go back in and make it better? Do you put out a double album? There's been all sorts of discussions about what we want to do with that stuff, and we may just even put it out there, kind of like what Beyonce did, with no promotion beforehand. But there's really no definite plans yet."