The invention relates to a tap for beer barrels, comprising a tap casing with a valve and an outflow in addition to a beer duct which is connected to said casing and is used to pierce the barrel. Said beer duct is engulfed by a movable sheath with a compressed seal against which a muff can be screwed. Also provided are means for securing the tap casing in relation to the sheath and the muff in a position which opens the bung hole of the barrel. A toothed ring is rotationally arranged on the beer duct between two stops. Said ring interacts with the similarly toothed muff like a ballpoint pen.
