A blender, or liquidiser in British English, is a kitchen appliance used to mix ingredients or puree food. The term typically refers to a stationary, upright electrical device, which is to be distinguished from a hand-powered or electric mixer that may be used for similar purposes. Blenders are also used in laboratory applications.

The blending container can be made of glass, plastic, stainless steel, or porcelain, and often has graduated markings for approximate measuring purposes. At the top of the container is a lid to prevent ingredients from escaping during operation. At the bottom is a blade assembly, sometimes removable for cleaning purposes. In cases where the blades are removable, the container should have an o-ring between the body of the container and the base to seal the container and prevent the contents from leaking.

The container rests upon a base that contains a motor for turning the blade assembly and has controls on its surface. Most modern blenders offer a number of possible speeds. Low-powered blenders require some liquid to be added for the blender to operate correctly. This is because the liquid is used to move the solids around the jar and bring it in contact with the blade as the "whirlpool" fluid movement brings items from the top to the bottom. High-powered blenders are capable of milling grains and crushing ice without such assistance.

Another type of blender is the immersion blender. This has no container of its own, but instead has a mixing head with blades that can be immersed in a pot of soup, for example.

Some of the functions of blenders have been taken over by food processors. In particular, thicker mixtures such as mayonnaise and hummus are easier to make in food processors.

Applications
Blenders are used both in home and commercial kitchens for various purposes, such as

• Mix and crush ice in cocktails such as the Zombie, Piña Colada and frozen margaritas
• Crush ice and other ingredients in non-alcoholic drinks such as Frappucinos and smoothies
• Emulsify mixtures
• Make smooth purées of semi-solid ingredients, such as cooked vegetables and meat
• Reduce small solids such as spices and seeds to powder or nut butters
• Blend mixtures of powders, granules, and/or liquids thoroughly
• Help dissolve solids into liquids
• Blenders also have a variety of applications in microbiology and food science. In addition to standard food-type blenders, there is a variety of other configurations of blender for laboratories.

Development

It is popularly believed that Dr. Oliver Johnson Schofield, an English engineer and entrepreneur, invented the first electric blender in 1921. However, Polish-American Stephen J. Poplawski, owner of the Stevens Electric Company, began designing drink mixers in 1919 under contract with

Arnold Electric Company, and patented the drink mixer in 1922 which had been designed to make Horlicks malted milk shakes at soda fountains. He also introduced the liquefier blender in 1922. Stevens Electric was sold to Oster Manufacturing, a manufacturer of barber equipment, in 1946. Oster commercialized the liquefier blender under the trademark Osterizer. Oster was bought by Sunbeam Products in 1960.

In 1935, Fred Osius invented another kind of blender. He approached Fred Waring, a popular musician who financed and promoted the "Miracle Mixer", which was commercialized in 1937 by Waring Products, now part of Conair. Waring popularized the smoothie in the 1940s. Waring long used the spelling "blendor" for its product.

With the rising popularity of smoothies, Frappucinos and other frozen drinks prepared in front of the customer, new models of commercial blenders often include a sound-reducing enclosures and computerized controls.

Specialized blenders for making smoothies are becoming popular, chiefly resembling an ordinary model with a spigot added for quick serving. Some models also feature a gimballed stirring rod mounted on the lid, constructed so that mixtures can be stirred whilst the machine is running with no chance of the stirrer fouling the blades.

Mechanical operation
The powertrain of a blender.A blender consists of a housing, motor, blades, and food container. A fan-cooled electric motor is secured into the housing by way of vibration dampers, and a small output shaft penetrates the upper housing and meshes with the blade assembly. Usually, a small rubber washer provides a seal around the output shaft to prevent liquid from entering the motor. Most blenders today have multiple speeds.