Abstract: An apparatus for controlled blowing of asphalt comprises a stator block, a rotor, a motor, a gap, a gas conduit, and a porous plug. The rotor resides within a cylindrical interior chamber of the stator block. When engaged, the motor causes the rotor to rotate about the longitudinal axis of the rotor. A porous plug is within a gas conduit at an opening into the interior chamber of the stator block. The porous plug allows the gas to pass from the gas conduit into the gap as tiny bubbles. In this way, the asphalt continuously enters the apparatus at the inlet end of the interior chamber, passes through a gap between the interior chamber and the rotor where gas is blown through the porous plug and into the asphalt while the motor rotates the rotor, and exits the apparatus at the outlet end of the interior chamber as blown asphalt.