Design considerations in coffeemakers

While coffee percolators in particular were seemingly locked into an extremely traditional design vocabulary, vacuum coffee makers were able to have a more diverse expression, since the colonial coffee pot was not a practical form for this type of device, which required two fully separate chambers joined in an hourglass configuration. Interest in this method revived around 1914-1916 with the increasing popularity of the ‘Silex’ brand, based on models developed by Massachusetts housewives Ann Bridges and Mrs. Sutton. Their use of Pyrex solved the problem of fragility and breakability that had made this type of machine commercially unattractive. The popularity of glass and Pyrex globes was reinforced during the Second World War, since aluminum, chrome, and other metals used in traditional percolators became restricted in availability. The sleek and simple forms attracted positive attention from design critics influenced by functionalism of the Bauhaus, and the exigencies of wartime design. Science’s influence as a motif in post-war design was felt in the manufacture and marketing of coffee and coffee-makers. Consumer guides emphasized the ability of the device to meet standards of temperature and brewing time, and the ratio of soluble elements between brew and grounds. The industrial chemist Peter Schlumbohm expressed the scientific motif most purely in his ‘Chemex’ coffeemaker, which from its initial marketing in the early 1940’s used the authority of science a sales tool, describing the product as ‘the Chemist’s way of making coffee’, and discussing at length the quality of its product in the language of the laboratory: “the funnel of the CHEMEX creates ideal hydrostatic conditions for the unique...Chemex extraction.” Schlumbohm’s unique brewer, a single Perspex vessel shaped to hold a proprietary filter cone, resembled nothing more than a piece of laboratory equipment, and became wildly popular in the technology-obsessed 1950’s household.
Drip coffeemakers
A drip coffee maker can also be referred to as a dripolator. A number of different machines used to automate these methods were around until the mid-20th century. In 1972, the first automatic drip-brew coffeemaker for home use, Mr. Coffee, was introduced (Braun had come out with an automatic drip-brew machine for commercial use in 1963). It combined aspects of both the drip-brew process and the percolating process with the added feature of heating up the water using an electric element in a separate chamber. Since that time, the number, style, and size of these appliances have increased dramatically

Vacuum brewers

Other coffee brewing devices became popular throughout the nineteenth century, including various machines using applications of the vacuum principle. The Napier Vacuum Machine, invented in 1840, was an early example of this type. While generally excessively complex for everyday use, vacuum devices were prized for producing a clear brew, and were actually quite popular up until the middle of the twentieth century.
The principle of a vacuum brewer was to heat water in a lower vessel until expansion forced the contents through a narrow tube into an upper vessel containing ground coffee. When the lower vessel was empty and sufficient brewing time had elapsed, the heat was removed and the resulting vacuum would draw the brewed coffee back through a strainer into the lower chamber, from which it could be decanted. The Bauhaus interpretation of this device can be seen in Sintrax coffee maker of 1925.
An early variant technique, called a balance siphon, was to have the two chambers arranged side-by-side on a sort of scale-like device, with a counterweight attached opposite the initial (or heating) chamber. Once the near-boiling water was forced from the heating chamber into the brewing one, the counterweight was activated, causing a spring-loaded snuffer to come down over the flame, thus turning "off" the heat, and allowing the cooled water to return to the original chamber. In this way, a sort of primitive automatic brewing method was achieved.

Percolators

Percolators began to be developed from the mid-nineteenth century, with James Nason patenting a version in Massachusetts in 1865. In both biggin and percolator devices, however, similar functional requirements are central: gravity or pressure is used to move water into contact with coffee for a sufficient amount of time to infuse an acceptable amount of flavor, and then those same forces act to remove the brewed coffee from the grounds, which to the greatest extent possible, are kept separate from the finished product. Domestic electrification simplified the operation of percolators and vacuum systems and made them ubiquitous in American homes. A critical element in the success of the electric coffee maker was the creation of safe and secure fuses and heating elements. In an article in House Furnishing Review, May 1915, Lewis Stephenson of Landers, Frary and Clark described a modular safety plug being used in his company’s Universal appliances, and the advent of numerous patents and innovations in temperature control and circuit breakers provided for the success of many new percolator and vacuum models. Notable new models included Farberware’s Coffee Robot (introduced in 1937), the Knapp-Monarch Therm-a-Magic (1931), and the very popular Sunbeam Coffeemaster introduced in 1940. Sunbeam was one of the first manufacturers to move away from the all-glass construction (prized for maintaining purity of flavor), to nickel-plated copper