Biscuit (also known as bisque) refers to any

pottery Pottery is the process and the products of forming vessels and other objects with clay and other raw materials, which are fired at high temperatures to give them a hard and durable form. The place where such wares are made by a ''potter'' is al ...

that has been fired in a kiln without a

ceramic glaze Ceramic glaze, or simply glaze, is a glassy coating on ceramics. It is used for decoration, to ensure the item is impermeable to liquids and to minimize the adherence of pollutants. Glazing renders earthenware impermeable to water, sealing th ...

. This can be a final product such as biscuit porcelain or unglazed

earthenware Earthenware is glazed or unglazed Vitrification#Ceramics, nonvitreous pottery that has normally been fired below . Basic earthenware, often called terracotta, absorbs liquids such as water. However, earthenware can be made impervious to liquids ...

(such as

terracotta Terracotta, also known as terra cotta or terra-cotta (; ; ), is a clay-based non-vitreous ceramic OED, "Terracotta""Terracotta" MFA Boston, "Cameo" database fired at relatively low temperatures. It is therefore a term used for earthenware obj ...

) or, most commonly, an intermediate stage in a glazed final product. Confusingly, "biscuit" may also be used as a term for pottery at a stage in its manufacture where it has not yet been fired or glazed, but has been dried so that it is no longer plastic (easily deformed). The porous nature of (fired) biscuit

means that it readily absorbs water, while vitreous wares such as

porcelain Porcelain (), also called china, is a ceramic material made by heating Industrial mineral, raw materials, generally including kaolinite, in a kiln to temperatures between . The greater strength and translucence of porcelain, relative to oth ...

bone china Bone china is a type of vitreous, translucent pottery, the raw materials for which include bone ash, feldspathic material and kaolin. It has been defined as "ware with a translucent body" containing a minimum of 30% of phosphate derived from c ...

and most

stoneware Stoneware is a broad class of pottery fired at a relatively high temperature, to be impervious to water. A modern definition is a Vitrification#Ceramics, vitreous or semi-vitreous ceramic made primarily from stoneware clay or non-refractory fire ...

are non-porous even without glazing. The temperature of biscuit firing is today usually at least 1000°C, although higher temperatures are common. The firing of the ware that results in the biscuit article causes permanent chemical and physical changes to occur. These result in a much harder and more resilient article which can still be porous, and this can ease the application of glazes. In situations where two firings are used, the first firing is called the biscuit firing, and the second firing is called the

glost firing Ceramic glaze, or simply glaze, is a glassy coating on ceramics. It is used for decoration, to ensure the item is impermeable to liquids and to minimize the adherence of pollutants. Glazing renders earthenware impermeable to water, sealing th ...

, or glaze firing if the glaze is fired at that stage.

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External links

{{DEFAULTSORT:Bisque (Pottery) Pottery Ceramic materials