Kitchen utensil the turn of the 20th century, Maria Parloa noted that kitchen utensils were made of (tinned or enamelled) iron and steel, copper, nickel, silver, tin, clay, earthenware, and aluminium. The latter, aluminium, became a popular material for kitchen utensils in the 20th century. Copper has good thermal conductivity and copper utensils are both durable and attractive in appearance. However, they are also comparatively heavier than utensils made of other materials, require scrupulous cleaning to remove poisonous tarnish compounds, and are not suitable for acidic foods. Copper pots are lined with tin to prevent discoloration or altering the taste of food.
Tin-glazing of tin glazes may differ in different sites and periods, the process of the production of tin glazes is similar. Generally speaking, the first step of the production of tin glazes is to mix tin and lead in order to form oxides, which was then added to a glaze matrix (alkali-silicate glaze, for example) and heated. After the mixture cooled, the tin oxide crystallises as what has been mentioned above, therefore generates the so-called white tin-opacified glazes. Besides, the body of tin-opacified wares is generally calcareous clays containing 15-25% CaO, of which the thermal expansion coefficient is close to that