Selecting a Mortar and Pestle on Amazon.com
A mortar and pestle is used to grind and mix substances. The mortar is a bowl and the pestle is a small, dense club for crushing and pounding a substance against the mortar. Mortars vary in diameter and capacity, and may have a spout for pouring contents. Pestles vary in handle length, head diameter, and head shape. While usually paired in a set, mortars and pestles are available individually.
Among the factors to consider when choosing the best mortar and pestle material for an application are hardness and porosity. In general, a mortar and pestle set must be hard enough to withstand grinding. For applications where sample purity must be maintained, the set must be nonporous to prevent cross contamination. Porcelain mortars are sometimes glazed on the outside to resist absorption, but unglazed on the inside to provide a rough surface for grinding.
Ceramic, glass, metal, plastic, and stone are materials from which mortar and pestles may be made. The mortar and pestle are usually made of the same material, but they may differ. Some pestles have a wooden handle for strength while the head is made of porcelain. Ceramics, such as porcelain and alumina, withstand high temperatures and provide more durability and finer grinding than glass, but are porous to varying degrees. Alumina, in particular, is very hard and wear-resistant. A glass mortar and pestle, though more fragile than other materials, resists stains and works well for substances with a high liquid content. Metal provides extreme durability, though some metals must be oiled, making them unsuitable for certain applications. To avoid contamination, disposable plastics may be used. Stone, such as agate and onyx, resists abrasion from hard substances and can be highly polished to minimize contamination.
Specialized types of mortar and pestle include a liquid nitrogen-cooled type for pulverizing tissue samples and an impact type with a metal vial and ball for crushing ore samples. In laboratories and for large-scale mixing operations, an automatic mortar grinder can be set to grind for a certain duration and intensity to provide consistent, reproducible results. Mortar & pestle sets are commonly used in scientific and pharmaceutical applications as well as food preparation.