Old Style Pressure Cookers

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There are basically two types of pressure cookers, the older, first generation models and the newer models. The main difference between the two types of pressure cookers is the valve. The older models have a moving or "jiggling" weight valve on the top, while the newer, second-generation ones use a one-piece spring valve which makes it easier to know what the actual pressure is and therefore much easier to adjust. Generally, there are fewer features and less safety measures in this type of cooker.

American manufacturers seem to be slow in changing to the more modern cookers that are made by most European, and even some Asian manufacturers. Recent additions include some hybrid pressure cookers that still have a jiggle top, but incorporate some of the modern safety features typically found in the newer style pressure cookers. These models may also offer some type of quick release method. The older style, first-generation models are still being made and they are in wide spread use. They may be made of stainless steel or aluminum and tend to be lower-priced than the newer, improved models. If you are on a tight budget, they are an affordable alternative to the higher priced, new generation models.

Most first-generation pressure cookers most use a single pressure which may be lower than the standard of 15psi. Some models may have a dual weight, or separate weights, that allow for different pressures. When buying a pressure cooker that only has one pressure setting, make sure it is capable of reaching the standard operating pressure of 15psi. This is the standard, and the majority of pressure cooker recipes are designed for this setting. If the operating pressure is lower than 15 pounds, you will not realize as much time or energy savings, and you will always be adjusting recipes to fit. Find out more about the standard pressure settings here.

Generally, the first generation P/Cs have only two methods to drop the pressure. The Cold Water Release in which you place the pressure cooker in the sink and run cold water over it to bring down the temperature and pressure. Or the Natural Release in which you wait until pressure drops on it's own. Find out more about pressure release.

The Pressure Regulator

This is the famous 'jiggle top', or weighted pressure regulator, that sits atop the vent pipe on first generation pressure cookers.

This weight rocks back and forth and makes the notorious hissing and spitting noises so often associated with traditional pressure cookers. Up to 1/3 the amount of liquid inside the pressure cooker may be lost in some jiggle top models. The regulator rises up on the vent pipe when pressure is achieved, and begins to rock or jiggle, hence the common name of jiggle top. When pressure is achieved there is a lot of noise, some hissing, spitting and escaping steam from the built up pressure. At this point you lower the heat until the regulator is moving only about 3-5 times per minute. Any more often than that would indicate that the pressure cooker is over pressurized and trying to sent all that excess pressure. With the heat properly adjusted you should see less steam and hear a softer hissing of escaping steam.

Variations

Some models have snap on, or fixed weight that is stationary. The regulator rises up on the vent pipe when pressure is achieved, but it does not rock or jiggle. It is somewhat more difficult to monitor the pressure on this type of cooker because you have to rely more on the sound.. When pressure is achieved there is a lot of noise from venting steam, at that point you lower the heat. Properly adjusted, you should see less steam and hear a softer hissing of continuously escaping steam.

Both types of cookers to lose much more water in the normal cooking process than the second-generation models. take the Test Drive to see how much water your particular model uses. There's nothing wrong with the first-generation type of pressure cookers, they just lack the ease of use, improvements and additional safety features of the newer second-generation models available today. Many companies are still manufacturing the older style pressure cookers, and the designs have not changed dramatically since pressure cookers were invented in the early part of this century. Many older models, including my 30 year old Presto, are still in regular use.

Safety Features

Modern pressure cookers offer many safety mechanisms that make sure you won't accidentally blow the lid.

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Weight Release Valve  The weight valve maintains the pressure necessary for thorough cooking and releases small excess pressure.

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Gasket Release System:If the weight valve fails to function due to overload or blockage of the bent tube, the pressure inside the cooker is likely to go above the normal level. A portion of the gasket is then pushed out through a slot in the lid, releasing excess steam safely downwards.

prestige-metalrelief.gif (15242 bytes)Metallic Safety Valve: The metallic safety valve contains a special, fusible alloy pellet that melts when the temperature and pressure rises beyond a safe level. This allows all pressure to be released at once. The safety valve must be replaced if it melts.

prestige-doublelocking.gif (15138 bytes)Double Locking System: The double locking system ensures that the cooker cannot be opened until pressure returns to normal

The Lock Pin, located on the cover handle, engages with the air vent/cover lock to prevent the cover from being opened when there is pressure in the unit.

 

 

 

 

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