With coffee from places like Brazil, Kenya and Sumatra, South Brisbane's Roastery Cafe built its reputation on exotic blends. But another blend reportedly sitting in the back warehouse was far more valuable.

Police allege Roastery and its coffee distribution brand Rouge were a front for a "highly sophisticated" drug distribution network, sourcing methamphetamines and precursor chemicals from Sydney for more than three years.

Items seized in the raids on a South Brisbane cafe.

After gathering intelligence for two years, police pounced in a dawn raid on Friday morning and also searched 18 other properties in Queensland.

Before the raids Roastery's main claim to fame was a growing reputation as one of the city's coffee kings. It was so good people would pay $295 for barista classes.