Hold or soak
Hold, also called soak, is a crucial phase within the ceramic firing cycle, during which the kiln temperature remains stable for a set period of time before cooling is initiated. This stage is not simply a thermal pause; it is the time when key chemical reactions are completed, the structure of the ceramic material is stabilized and proper vitrification of both the body and the glaze is ensured.
In bisque firings, the soak allows the residual moisture to be completely removed and any organic matter present to be burned off. In this way, the clay hardens and acquires the ideal porosity to receive the glaze at a later stage. In glaze firings, the soak ensures that the glazed surface melts uniformly, that the pigments develop with the right intensity and brilliance, and that the pieces acquire optimum mechanical strength.
In some traditional kilns, the hold is achieved by careful control of fuel and air currents, maintaining stable temperatures for hours. This mastery of temperature was, historically, one of the great skills of ceramists, who evaluated progress by observing the color of the fire, the flow of smoke or the bending of pyrometric cones.Interesting Fact
The soak phase can also be used to introduce colorants or special effects into ceramics. During this constant temperature phase, some ceramists experiment with adding metal oxides, salts or vapors inside the kiln. These elements react with the surface of the pieces, generating unique patterns and colors that could not be obtained in any other way.Helpful Tip
Record each firing cycle in detail, noting the duration and temperature of the hold, as well as the results on the glaze and clay. With this information, you will be able to adjust your practices in future firings and achieve greater consistency and control over the final results.
