Devices for use in a water injection coffee extraction machine are in a form of a hollowed ring which may be fixed about the base of the extraction head of the coffee machine, and a grill or other member, which allows passage of extraction water therethrough, is positioned transversely within the interior of the ring so that upon fitting the ring about the extraction head base, the grill or other member is positioned adjacent the base of the extraction head. The grill may have projections which extend in a direction away from the extraction head, and the member may have a centrally disposed portion which has a form of a needle which also contains at least one hole.