Slide 9: Pre-Firing

Here a potter of the Konate family in the village of Ouri in Burkina Faso prepares to fire five large jars that will be used for brewing millet beer. The humidity of much of West Africa does not permit pots to become sufficiently dry for the type of firing used in Africa. To drive the last molecules of absorbed water from between the clay particles the pots are often pre-fired. To pre-fire larger pots, they are turned rim downward on three large stones which keep them off the ground. A small fire is built beneath each pot to complete the drying process. When the pots are sufficiently dry, they are stacked with others for the final firing, or the potter may simply begin to pile larger amounts of fuel around them and fire each pot individually. The final firing must be begun before the pots have cooled from the pre-firing. If pottery is allowed to cool after the pre-firing, it will re-absorb moisture from the atmosphere and will crack during the final firing.

Supplementary Information on Why Pre-firing is Necessary in Africa

Pre-firing is necessary because of the rapidly increased temperature of the African firing. As pottery is fired, any water that remains between the clay particles will turn to steam and burst the pot. Western potters avoid this problem by starting their kilns at very low heat, allowing any traces of moisture to evaporate slowly before increasing the kiln temperature. Pre- firing is usually not necessary in the dry savanna where the lack of humidity permits more complete drying of the pottery before firing.

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