Collective term for all products (majolica, porcelain, earthenware, stoneware), which are produced from different types of clay by firing. The differences between the various products result from the different mixture of raw materials (clay, quartz, feldspar, calcite, etc.) and above all from the firing temperature. Stoneware is fired at less and stoneware is fired at more than 1,200 °C; therefore, stoneware must be glazed to ensure sufficient density. Vessels made of such material are the oldest used for the production and storage of wine. Examples are the amphorae already used in ancient times or the well-known Georgian Kvevri in the cachetic process. Today, ceramic vessels are increasingly used for fermentation, ageing and storage. The advantages are (as with glass) complete neutrality, i.e. there is no reaction with must or wine. The disadvantage is the relative fragility (cracks). See also under wine vessels.