An infusion device (i) is described for rapidly brewing e.g. fresh fine ground roasted coffee, by air agitation in an air-water chamber. (i) basically comprises a drinking straw (air conduit) sealed at 1 end; a measured amount of coffee in filter paper is attached to the straw near the sealed end by ring clamps. The straw also has slits near the seal. (i) is immersed in a hot water container (e.g. a single service cup). Air is blown (manually or pumped) into the straw, through the slits into the coffee 'bag'; water solubles of the coffee are rapidly extracted and forced through the paper to mix with the remaining water.