A machine produces foam-in-bag from foam precursors mixed within the bag. The machine comprises a base and a shell. The base and shell are moveable relative each other between a base/shell disengaged position and a base/shell engaged position. In the base/shell engaged position, the base and shell divide the bag so that a mixing chamber is isolated from the remainder portion of the bag. First and second nozzles inject foam precursors into the mixing chamber. A mixer engages the mixing chamber to provide mixing energy to facilitate the foam reaction.