Denis Papin Invents the Pressure Cooker

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Denis Papin Invents the Pressure Cooker

Overview

A pressure cooker is a vessel that uses steam under high pressure for cooking food. It offers a number of benefits, including fast, often low-fat cooking that preserves the minerals—and even the coloration—of fruits, vegetables, and meats. For Americans born in the twentieth century, pressure cookers were a familiar part of home life, so much so that they had come to seem positively old-fashioned by the 1990s, when they began making a comeback among health-conscious consumers. In fact the genesis of the pressure cooker dates back to a 1679 invention by French physicist Denis Papin (1647-1712), though it would be many centuries before a modified version of his "steam digester" would be adapted for household use.

Background

Many of the features associated with the modern kitchen and dining room are more recent in origin than most modern people would imagine: the plate, for instance, did not make its debut among the common people until the sixteenth or seventeenth century. Much of a cook's work was done by methods that had persisted more or less unchanged since prehistoric times. Until the stove appeared in the 1600s, the vast majority of cooking was done over an open fire, or more rarely, in a rudimentary oven. Even in the latter case, fire provided the heat.

Fire would also be the source of heat in the steam digester, though the significance of Papin's innovation was that it introduced a new medium between the flame and the food it cooked: steam. In fact the road to Papin's invention was not a direct one, because his chief concern was not cooking but steam pressure and power.

The last real progress in steam power prior to Papin's time dated back some 1,500 years, to Hero of Alexandria (fl. first century a.d.). Hero's aeliophile consisted of a sphere resting on two hollow tubes, themselves connected to a steam-producing boiler. The heated steam escaped through the hollow tubes, which then caused the sphere to whirl. It was an interesting invention, but really nothing more than a curiosity—rather like the wheels created by the Olmec of ancient Mesoamerica, who used them only in making children's toys, and failed to grasp their use in providing traction for transportation, agriculture, and building projects.

Papin himself began his career working not on steam, but on air pumps, as an assistant to physicists Christiaan Huygens (1629-1695) and Robert Boyle (1627-1691). He worked with Huygens in Paris from 1671 to 1675, then with Boyle in London until 1679, the year he presented his steam digester to the Royal Society. No doubt the heightened atmosphere of curiosity and experimentation associated with the Royal Society, one of the most influential scientific institutions in world history, had an effect on his thinking. In any case, it was during this period that he developed the idea of using steam as a form of power.

Papin first demonstrated his "New Digester for Softening Bones" before the Royal Society on May 22, 1679. To modern eyes, it was an ungainly looking contraption, a far cry from the compact pressure cookers that would later appear in modern kitchens. Shaped rather like a potbellied stove, the digester consisted of a raised metal cylinder containing a glass vessel. Papin filled the cylinder with water equal to the difference in volume between the glass container and the cylinder itself, then placed some meat into the container, added liquid to it, and sealed it. He then applied heat from a fire beneath the cylinder, using a built-in safety valve to release excess steam once the interior of the container had reached the necessary pressure.

The gentlemen of the Royal Society were pleased to discover that the steam digester cooked the meat quickly and thoroughly, producing a dish far more tender and tasty than a similar item cooked over a fire. The key element was the steam, which increased the pressure and—because of the relationship between pressure and temperature—heated the meat more quickly than a mere fire could have. As a result of cooking faster, the food retained more of its flavor and (though this was a fact far beyond the knowledge of scientists in the seventeenth century) its nutritional content.

Another aspect of scientific knowledge yet to make its appearance at the time was an accurate means of measuring temperature. That would have to wait for two men who were not even born at the time: Daniel Fahrenheit (1686-1736) and Anders Celsius (1701-1744), who produced their respective temperature scales in the following century. Because the pressure cooker did its work so quickly, it was important to have some idea when the meat was cooked, so as to avoid overcooking—but for safety, this had to be done without lifting the lid.

Papin devised an ingenious method for overcoming this challenge. He had a depression built into the top of the pressure cooker, and into this he placed a drop of water. He could then see when the water boiled, and using a three-foot pendulum, he was able to time the interval necessary for boiling as well as for evaporation. He also weighed the coal necessary to operate the pressure cooker, as a means of measuring the instrument's efficiency.

Impact

Though Papin's invention would ultimately have a great impact in the kitchen, its influence was still greater, because in fact what he had created was a forerunner of the piston and cylinder mechanism later incorporated into engines. When the cold water inside the cylinder was heated, this raised the "piston"—i.e., the cooking vessel. This in turn created a partial vacuum, and as a result, the outside air pressure forced the piston downward. Of course in the case of the pressure cooker, the purpose was not to force the cooking vessel toward the bottom of the cylinder, but simply to produce the pressure necessary for cooking; nonetheless, the principle of the active piston stroke had made its appearance.

Sir Christopher Wren (1632-1723) of the Royal Society commissioned Papin to write a booklet concerning his invention, and Papin went on to conduct experiments with the idea of a steam engine. In 1690 he produced an atmospheric engine using a tube, three inches (7.6 cm) in diameter and sealed at one end, that contained a movable piston. The tube was filled with cold water that, when heated, converted to steam. This caused the tube to rise; then as the steam cooled and condensed, the atmospheric pressure forced the piston to move downward to its original position.

In 1698 English inventor Thomas Savery (1650-1715) developed a pump used for removing water from flooded mines. Papin studied Savery's pump, which did not include a piston, and concluded that the addition of the latter would make a more effective engine. He also improved on Savery's idea of a boat propelled by side paddles, which though it seemed impractical to many at the time, would obviously offer great advantages over either human or wind power.

Savery himself, failing to see the implications of steam in this instance, had intended to use muscle power for operating the paddles, whereas Papin's paddle wheel—prefiguring the idea of a steamboat—used steam. Unfortunately, the vessel was destroyed, apparently by river boatmen who feared a challenge to their means of livelihood. The full realization of the steam engine itself would have to wait for Thomas Newcomen (1663-1729), who produced his in 1712, the same year that Papin died.

Ironically, the man who created the pressure cooker, and played a major role in the use of steam power, died poor and largely forgotten. The pressure cooker, too, lingered in obscurity for many years, and when it finally did receive attention, it was not used for the application most commonly associated with it today. Rather, as scientists in the centuries that followed came to recognize the value of sterilization in the medical environment, the pressure cooker entered service as a sterilizer for metal instruments.

The first notable culinary application of the pressure cooker after Papin's time came in 1810, when French chef and confectioner Nicolas François Appert used it for boiling sealed containers of food. Thus was born the canning industry, which made it possible to preserve foods indefinitely, and to transport them anywhere.

At the beginning of the twentieth century, when other innovations such as the harnessing of electrical power served to facilitate the use of the pressure cooker for home use, the appliance finally began to appear in the kitchen. The term "pressure cooker" itself first appeared in print in 1915, and by the 1920s pressure cookers themselves had made their way into the homes of wealthy and middle-class consumers. At the World's Fair in 1939, National Presto Industries presented what became the first widely popular commercial pressure cooker.

World War II proved to be a boon for the pressure cooker, when wartime shortages of energy forced American homemakers to seek more energy-efficient means of cooking. As a result, baby boomers grew up on meals cooked in the appliance, which became as much a fixture of 1950s and 1960s households as television sets and frost-free refrigerators. Pressure cookers were particularly useful for people living in high-altitude areas, where lowered atmospheric pressure required longer cooking times for foods prepared with a traditional oven or stove.

The pressure cooker proved so popular, in fact, that it had come to seem rather passé by the 1970s and the 1980s. Fear of dangers associated with high-pressure cooking may also have had something to do with its waning use: an episode of the highly popular I Love Lucy television show during the 1950s, for instance, featured a pressure cooker that exploded, sending hot food flying all over star Lucille Ball's kitchen. Pressurecooker manufacturers responded by adding safety features such as locks, pressure regulators, and low-pressure fryers. These measures, coupled with a growing interest in healthy eating, spurred a resurgence of interest in the pressure cooker during the 1990s.

JUDSON KNIGHT