"Lyrically, it was definitely [personal]," he says down the phone from Detroit, where he and Carney are enjoying a rare day off from their US tour.
"I was going through a break-up. It was right while we were making the record [so] it was pretty much impossible for me to focus on anything other than that because I was just so wrapped up in it.
"It's definitely reflected in the lyrics."
Auerbach's admission shows there's plenty to read into lines like "You're still just a mile away / But there's nothing left to say", from 10 Lovers, or "Why you always wanna love the ones who hurt you? / Then break down when they go and desert you", from Year in Review.
They're blatantly about last year's break-up with Stephanie Gonis, a four-year marriage that yielded a daughter of whom Auerbach has custody. According to TMZ, the subsequent divorce cost Auerbach $5 million, a house, a car and, oddly, a lock of Bob Dylan's hair.
Fans could be concerned that change in musical tact doesn't bode well for the duo's upcoming New Zealand tour in April, which will see the Keys play in Christchurch and Auckland. It will be their fourth time here after shows in 2005, 2008 and 2012 (they cancelled a Big Day Out appearance in 2011).
But Auerbach denies the gigs will be a downer, saying the Keys have recently performed some of the best shows of their 13-year career. They've got a new bass player, The Shins' Richard Swift, and a new visual display behind them, and Auerbach says the first shows on their recent US tour have been "amazing".
"I don't think we've ever sounded better as a four-piece. I know the shows have been going great. It's really obvious. The crowds have been really receptive and the playing's been fun, so that's really all that matters."
Reviews prove Auerbach's right: of their recent homecoming show in Ohio's Schottenstein Centre, a Columbus Alive reviewer said they "moved from one blistering cut to the next with workmanlike fervour", and JSOnline reported that in Wisconsin, Auerbach "was a dude out to have a good time, jamming with his buds for his fans".
We're always thinking about making records, man - it's our favourite thing to do. We'd make 20 records a year if we could be in the studio all the time. If people paid for albums these days, maybe we could be in the studio a little more, but we've gotta hit that road.
Not that Auerbach cares about reviews. He doesn't read them. Why? "Even when they're positive I disagree with the reasons they're positive," he says. "Who cares? It doesn't really matter either way."
And Auerbach has a warning for Kiwi fans: if you're into it, The Black Keys will bring it.
"It doesn't really matter what size the venue is, if the audience is excited and into it, it's going to be fun. We sure as shit played a million tiny little venues that were not fun, where the audience was boring and they had their arms crossed. They were intensely watching, but absolutely boring. If the crowd comes to get wild it's going to be fun."
As for those bluesy Turn Blue songs, Auerbach says they're playing "four or five of them" each night, and they "fit right in" among their rockier, rowdier material.
"They're doing really well, I think they fit in. We picked four or five Turn Blue songs, and four or five older songs from our back catalogue that we haven't played [for a while], and a new cover to play. It's been fun, we're mixing up the setlist every night."
You might think, given the divorce is only a year old, and he's just written an album full of heartbreak, that Auerbach might not be so keen on performing some of Turn Blue's songs live.
But Auerbach says tracks like the synth-driven Fever and the meandering Weight of Love take on a life of their own during live shows, especially when played for an up-for-it crowd.
"Writing them and creating them is completely different to performing them," he says.
"You're not reliving it, you're just performing a song, you know what I mean? The hard part is the creative process where you're really just sitting down by yourself thinking about it and obsessing over little details. When you're on stage and you're playing your parts and you're playing guitar and you're singing and guys are singing in harmony with you, and people are singing along with you, it's not the same."
For those fans in the front rows who might have been following the Black Keys since the beginning, they've witnessed a band go through several stylistic changes, from the rowdy garage-rock of 2004's Rubber Factory, to the classic rock of Brothers, to the chart-busting anthems of El Camino, and the more mature, melancholy sound of Turn Blue.
Despite their prolific output - eight albums in 13 years - Auerbach admits the Black Keys would record many more if they didn't tour so much.
Sometimes, they've hit the road a little too hard. Like in 2011, when they pulled out of the Big Day Out just a week before the festival to stay at home and record the songs that would ultimately become El Camino.
For that album, they performed 150 shows to support it, and Auerbach says that's not something they want to do again.
"It's not healthy to be on the road for a month at a time, especially when you have family. It's not a great way to live but it's the way that we live. It's what we do. It's like the blessing and the curse. We're doing so well at it, there's no way we could just stop doing it, but it's very taxing and it's not healthy.
"It is what it is and it's the only life we know. We've been doing it for more than a decade now and we're not really qualified to do anything else."
What: The Black Keys
Where and when: Horncastle Arena, Christchurch, April 18; Vector Arena, Auckland, April 19. Shows feature support from Band of Skulls
New album: Turn Blue, out now
- TimeOut
