Commercial tom yum paste is made by crushing all the herb ingredients used in tom yum (lemon grass, kaffir lime leaves, galangal, lime juice, fish sauce and crushed chili peppers) and stir-frying in oil. Seasoning and other preservative ingredients are then added. The paste is bottled or packaged, and sold around the world. Tom yum flavored with the paste may have different characteristics from that made with fresh herb ingredients.