Abstract: An apparatus for brewing compost tea from an aqueous compost mixture using only air bubbles as a means to circulate the mixture during fermentation. The mixture is held in a tank having a continuous sidewall and a conical bottom section with a central discharge opening. A plurality of equidistant conduits extend from the tank discharge opening to discharge nozzles having discharge ends at or just above the water level in the tank. A compressed air supply is joined by air lines to air diffusers in each of the conduits. During use, air is discharged from the diffusers to continually circulate the aqueous compost mixture upwardly in said conduits from the tank discharge opening to the discharge nozzles. The microorganisms grow rapidly in the aerated water, resulting in a rich compost tea. Due to the conical tank bottom and angled nozzles, the water swirls in the tank, creating a vortex.