The ROK is made from cast aluminium. The inner basket of the portafilter is stainless steel. All parts that contact the water or coffee in the ROK espresso maker are food-safe. The alloy is also a safe material although it actually makes no contact with the water or coffee. The water cylinder and plunger are made from Glass Composite with no BPA or Melamine. Our Black ROK is made of the same materials and has been finished with a powder coating.