A meeting of doom metal, hardcore and grunge, sludge was almost exclusively the preserve of New Orleans metallers in the late '80s and early '90s.
Musically it can be similar to doom, with detuned gurgling basslines. However, sludge is prone to suddenly shift tempo and is usually more abrasive than its lumbering cousin. Sludge vocals are often screamed or sung, owing more to early grunge acts than the spooky doom-mongers.
Key band: Down
Down were formed while Pantera was on a break between Far Beyond Driven and The Great Southern Trendkill. Their popularity pushed sludge across the States and beyond.
Key album: Crowbar - Crowbar (1993)
Produced by Phil Anselmo of Pantera and Down, Crowbar’s second album plucked them from obscurity and got sludge metal on MTV.
Key track: Eyehategod - Dixie Whiskey (1996)
If you like your metal with a touch of blasphemy, Eyehategod are the sludgers to go to first.
Sludge metal band list