direct high heat can shatter them Heatresistant forms of glass incorporate an oxide of boron that has the effect of reducing thermal expansion by a factor of about 3, and for this reason are less affected by thermal shock, though they’re still not immune Enamelware In utensils called enamelware, powdered glass is fused into a thin layer onto the surface of iron or steel utensils This was first done to cast iron early in the 19th century, and today enameled metal is widely used in the dairy, chemical, and brewing industries, as well as on bathtubs In kitchen utensils, the metal diffuses the direct heat evenly, the ceramic layer is thin enough that it can expand and contract uniformly, and it protects the food from direct contact with the metal Enamelware is reasonably durable, though it still requires some care: the ceramic layer can be chipped or damaged by quenching a hot pan in cold water The Advantages of Poor Conductivity The poor conductivity of ceramic materials is an advantage if the cook needs to keep food hot Good conductors like copper and aluminum quickly give up heat to their surroundings, while ceramics retain it well Similarly, ovens with ceramic (brick) walls are unparalleled for the evenness of their heating The walls slowly absorb and store large quantities of energy while the oven is heated up, and then release it when the food is placed inside Modern metal ovens can’t store much heat and so must cycle their heating elements on and off This causes large temperature fluctuations, and can scorch breads and other foods that are baked at high temperatures Aluminum Aluminum has been used in pots and pans for barely a century, despite the fact that it’s the most abundant metal in the earth’s crust It is ... quantities of energy while the oven is heated up, and then release it when the food is placed inside Modern metal ovens can’t store much heat and so must cycle their heating elements on and off This.. .The Advantages of Poor Conductivity The poor conductivity of ceramic materials is an advantage if the cook needs to keep food hot Good conductors like copper and aluminum quickly... fluctuations, and can scorch breads and other foods that are baked at high temperatures Aluminum Aluminum has been used in pots and pans for barely a century, despite the fact that it’s the most abundant metal in the earth’s crust