When the hard and gritty blues make the jump from sweaty, dingy nightclubs to hockey arenas and major festival stages, questions of authenticity inevitably arise. Most of the time, these can be filed under the “sour grapes” heading, the uninvited input of the supposed gatekeepers of roots music. These are folks who believe that anything that becomes too popular can’t possibly be any good. (Sometimes, this argument holds water, it must be admitted.) Led Zeppelin and the Rolling Stones have both been described by a segment of the music-loving population as sell-outs over the years, musicians who supposedly exploited the blues for personal gain without really living the bluesman’s life.

The same criticism has been leveled at the Black Keys, and as was the case with Zeppelin and the Stones before them, it just doesn’t stand up to scrutiny. The Keys – guitarist/vocalist Dan Auerbach and drummer Pat Carney – have been playing a form of garage-blues, an electrified take on the primal rumblings that first emerged from the Mississippi Delta in the early decades of the previous century, from the beginning of their career. That the Keys now play that music in front of tens of thousands of listeners instead of a few hundred has not really changed the band’s sound, which is still rooted in deep blues and primal rock ’n’ roll.

At 8 p.m. Monday, one of our summer’s most highly anticipated shows takes over the Outer Harbor Concert Site (325 Furhmann Blvd.), with the Black Keys and the Joy Formidable. Gates will open at 6 p.m. Tickets are $48 (Ticketmaster, Town Ballroom box office and After Dark Entertainment box office).

Jeff Miers