Mortar and pestle

A mortar and pestle is a tool used to crush, grind, and mix substances. The pestle is a heavy stick whose end is used for pounding and grinding, and the mortar is a bowl. The substance is ground between the pestle and the mortar.

Etymology
The English "pestle" derives from classical Latin "pistillum", meaning "pounder". The classical Latin "mortarium" led to the English "mortar", meaning, among several other usages, "receptacle for pounding" and "product of grinding or pounding". The Roman poet Juvenal applied both "mortarium" and "pistillum" to articles used in the preparation of drugs, reflecting the early use of the mortar & pestle as a pharmacist's or apothecary's symbol as described below. The antiquity of these tools is well documented in some early literature, such as the Egyptian "Papyrus Ebers" of c. 1550 B.C.E. (the oldest preserved medical literature piece) and the Old Testament (Numbers 11:8 and Proverbs 27:22).

Medical use
Mortars and pestles were traditionally used in pharmacies to crush various ingredients prior to preparing an extemporaneous prescription. The mortar and pestle is the most common icon associated with pharmacies. For pharmaceutical use, the mortar and the head of the pestle are usually made of porcelain, while the handle of the pestle is made of wood. This is known as a Wedgwood mortar and pestle and originated in 1779. Today the act of mixing ingredients or reducing the particle size is known as trituration. Mortars and pestles are also used as drug paraphernalia in order to grind up pills to speed up absorption when they are ingested or in preparation for insufflation (snorting).

Food preparation


Mortars are also used in cooking to prepare ingredients such as guacamole and pesto (which derives its name from the pestle pounding), as well as grinding spices into powder. Native American tribes used mortars carved into the bedrock to grind acorns and other nuts. Many such depressions can be found in their former territories. Very large mortars are used with wooden mallets to prepare mochi. A regular sized Japanese mortar and pestle is called suribachi and surikogi. Granite mortars and pestles are used in Southeast Asia and India. In Malay, it is known as lesung. Traditional Mexican mortar and pestles, made of basalt, are known as molcajetes. Large stone mortars, with long (2-3 feet) wood pestles were also used in the Middle East to grind meat in order to prepare a type of meatloaf, or kibbeh, as well as the hummus variety known as masabcha.

Material
Good mortar and pestle-making materials must be hard enough to crush the substance rather than be worn away by it. They cannot be too brittle either, or they will break during the pounding and grinding. The material should also be cohesive, so that small bits of the mortar or pestle do not get mixed in with the ingredients. Smooth and non-porous materials are chosen that will not absorb or trap the substances being ground. In food preparation, a rough or absorbent material may cause the strong flavor of a past ingredient to be tasted in food prepared later. Also, the food particles left in the mortar and on the pestle may support the growth of microorganisms. When dealing with medications, the previous prepared drugs may interact or mix, contaminating the currently used ingredients.

Rough ceramic mortar and pestle sets can be used to reduce substances to very fine powders, but stain easily and are brittle. Porcelain mortars are sometimes conditioned for use by grinding some sand to give them a rougher surface which helps to reduce the particle size. Glass mortars and pestles are fragile, but stain-resistant and suitable for use with liquids. However, like the porcelain type, they do not grind as finely as the ceramic type. Other materials used include marble, stone, wood (highly absorbent), bamboo, iron, steel, brass, and basalt. Uncooked rice is sometimes ground in mortars to clean them. This process must be repeated until the rice comes out completely white. Some stones, such as molcajete, need to be seasoned first before use. Metal mortars are kept lightly oiled.

Automatic mortar grinder
Since the results obtained with hand grinding are neither reproducible nor reliable, most laboratories work with automatic mortar grinders. Grinding time and pressure of the mortar can be adjusted and fixed easily and work force can be saved. The first automatic Mortar Grinder was invented by F. Kurt Retsch in 1923 – the "Retschmill". Since then a lot of predecessors of this mill have been introduced up to the current model Retsch RM200.