Alshan Herbal Steam Stones are crumbled volcanic stones that have been specially heat treated to ensure that no bitter taste remains. They contain millions of tiny pores that allow them to effectively soak up the flavoured glycerine liquid that they are enhanced with, This process can also be completed at home when you want to re-flavour them yourself. When they are burned, the liquid evaporates and creates steam which allows you to blow clouds but without the harshness, allowing you to feel fully involved in the hookah process.