The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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A pressure cooker is a container with an airtight lid that traps steam from boiling water; the steam increases pressure inside the cooker, which raises the water's boiling point. The higher temperature cooks food much faster than usual. The pressure cooker includes a safety valve to prevent explosion if the steam pressure gets too high.
Both the device and the valve were invented in 1679 by the French physician Denis Papin, who called it a "steam digester." He demonstrated his invention to the Royal Society by reducing bones to an edible jelly. Papin described his "New Digester" in a 1681 pamphlet, emphasizing the fact that food cooked under pressure in this way retains flavor, color, and nutritive value that otherwise would be lost. In spite of these advantages, Papin's "digester" was used less for cooking than as an autoclave--a vessel that uses the high temperatures produced by steam under pressure to rapidly sterilize medical and scientific materials, an application in standard use today.
After the United States Department of Agriculture announced in 1917 that pressure cooking was the only safe way to preserve low-acid foods, home pressure cookers came on the market, but these were at first large and cumbersome to use. After World War II, many manufacturers began producing home devices, and pressure cooking became much more common. Today, pressure cooking methods are also used to cook wood chips so they become wood pulp that can be used to manufacture paper.