Porosity
Porosity is the property that determines the capacity of a piece to absorb liquids, due to the presence of small pores in its structure. This characteristic is directly influenced by the firing temperature and the degree of vitrification reached during the manufacturing process. Firing at lower temperatures results in more porous pieces, since the clay or glaze is not completely vitrified, allowing liquids to penetrate through the pores. Conversely, higher temperatures favor complete vitrification, significantly reducing porosity and making the piece less absorbent and impermeable.
For example, earthenware, fired at relatively low temperatures, tends to be porous and often requires an additional coating to make it impermeable, while stoneware and porcelain, fired at high temperatures, are naturally impermeable and suitable for the manufacture of tableware and utensils that come into contact with food and beverages. On the other hand, terracotta, with its high porosity, is ideal for pots, as it allows water and air to circulate, preventing waterlogging of plant roots.Interesting Fact
In ancient times, the porosity of ceramic vessels was a useful feature in the manufacture of water storage vessels. The pores allowed the contents to be kept cool by the process of evaporation through the porous walls of the vessel, acting as a natural cooling system.Helpful Tip
For utilitarian ceramics such as cups, plates or vases that must contain liquids, it is essential to apply a vitrified glaze that reduces porosity and prevents water from penetrating the piece. Consider the compatibility between the clay and the glaze to achieve optimum vitrification and minimize defects such as cracking or flaking.
