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By Instant Pot Staff, November 23, 2010

Electric pressure cookers have evolved substantially since the first patent was filed on January 9th, 1991.  Based on the cooking control capability, we can classify electric pressure cookers into three generations.

1^st Generation: Mechanical Timer

1st Generation Electric Pressure Cookers are Fitted with a Mechanical Timer

The 1^st Generation electric pressure cookers already have the essential pressure and temperature sensors. Both sensors act as a threshold moderator.  When either the threshold of pressure or that of temperature is reached, the power to the heating element is cut. The only user-accessible control is via the mechanical cooking time controller.  This mechanical controller offers estimated control on cooking duration.  There is no delayed cooking capability.

Basic safety mechanisms, such as locking the lid under pressure and excess pressure protection, have been implemented in the 1^st Generation cookers.

1^st generation electric pressure cookers are seldom seen in North America.  However, in Asia, they are still very popular with cost-conscience consumers.

2^nd Generation: Digital Controller

2nd Generation Electric Pressure Cookers Use Digital Controller

The 2^nd Generation electric pressure cooker builds on top of the capability of the 1^st generation with a digital controller.  Delayed cooking becomes possible.  Pressure sensor is also electronically connected to the controller, so that a count-down timer can be shown when working pressure is reached.

Safety is also improved with additional sensors.  Most notably, if the lid is not fully locked, pressure cooking would not start.  This avoids the potential risk of blowing up the lid under pressure cooking.

Many of the electric pressure cookers sold in the North America today are still 2^nd generation.

3^rd Generation: Smart Programming

3rd Generation Electric Pressure Cookers are Equipped with Smart Programming and Enhanced Safety

With the advance in pressure and temperature sensor accuracy, the 3^rd Generation electric pressure cookers implement sophisticate control with digital technology. Two most remarkable features are Smart Programming and Enhanced Safety. These features greatly improve cooking result, maintain consistence and enhance safety.

Each 3^rd Generation cooker is fitted with a microprocessor.  With the accurate readings from pressure and temperature sensors, the microprocessor can be programmed to perform complex cooking tasks. The Smart Programs are tailor made for specific cooking purpose by varying heating intensity, temperature, pressure and cooking duration, to achieve optimized cooking result and maintain consistence.  A typical example is in multigrain cooking program where the grains are soaked at ~60C/86F for a period to soften the grains before cooking starts. Please see our Smart Programming article for more details.

With the microprocessor programs, more sophisticated safety mechanisms become possible. For instance, one common mistake is misplacing the stream release at the open position while starting cooking. With the steam release open, pressure never builds up in the cooking pot. Earlier generation cookers would continue heating.  If the situation is not corrected on time, all liquid in the cooking pot would evaporate and the food would be spoiled. The 3^rd Generation cooker implements a mechanism called, Leaky Lid Protection, where the microprocessor detects the excess long pre-heating period and stops the heating with an alarm. More on the safety features here.

Instant Pot IP-CSG60 is a 3^rd Generation electric pressure cooker.

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By Instant Pot Staff, October 15, 2010

Instant Pot achieves the best cooking results with a set of smart cooking programs.  The programs are stored in and executed by an advanced micro-processor chip inside the Instant Pot control panel. Those programs have been chosen after extensive testing in our lab with various food content.

The smart cooking programs control the cooking process with four parameters: heating intensity, temperature, pressure and duration.

• Heating intensity refers to the amount of heat generated by the heating element. The main reason to control heating intensity is to manage the temperature at the bottom of the cooking pot, primarily to avoid burning food content at the bottom. For instance, heating is slower and gradually in “Soup” function whereas fast and steep in “Steam” (knowing there’s no food in contact to the cooking pot bottom). Heating intensity control is also used for soaking, such as in Multigrain function.  Instant Pot IP-CSG60 has a heating element with 1000W power rating.  The heat output of heating element is control by switching the power on and off for varying durations.
• Temperature is the cooking temperature in the cooking pot throughout the cooking process. The peak working temperature of Instant Pot is 115°C~118°C or 239°F~244°F. However, the smart cooking programs don’t always maintain at the peak temperature. In the “Multigrain” program, to soften the grains, the food content is heated to 60^oC for warm soaking for 50 minutes before cooking starts.
• Pressure: when the liquid content in the cooking port reaches the natural boiling point, which varies depending on the altitude of your location, steam builds up in the cooking pot and pressure is generated.  The thermodynamics of gas indicates that in ideal cases the product of the pressure and volume of a gas is directly proportional to the temperature.  Since the volume in the cooking pot is a constant, we can consider the pressure being linearly related to the temperature of the gas, and to large extent (with delaying effect) to the temperature of the liquid content. The working pressure of Instant Pot is 10.15~11.6 psi (pound-force per square inch).
• Cooking duration is the time the food content being cooked.  The cooking duration changes depends on the volume of the food content. For example, to cook 2 cups of rice, it takes about 14 minutes (8 minute pressure keeping time). More than 2 cups, it takes about 28 minutes (10 minute pressure keeping time).  Additional pressure keeping time ensures rice being cooked evenly in volume.  The default timing has been tested in our lab which works well in most cases. However, in situations when food needs to be well-done or less-cooked, the cooking duration can be adjusted with the “Adjust” button.

The smart cooking programs can be better understood with the visual temperature/pressure charts in relation with cooking time.  The following are the temperature/pressure charts of “Bean/Chili”, “Meat/Stew”, “Soup”, “Congee” and “Multigrain” cooking programs.

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By Instant Pot Staff, May 16, 2009

Instant Pot has 10 one-key operation buttons for the most common cooking tasks, including:

• Rice,
• Multigrain rice,
• Congee/Porridge,
• Sauté/Browning,
• Soup,
• Poultry,
• Meat & Stew,
• Beans & Chili,
• Steaming,  and
• Slow Cook

These one-button operation keys are carefully designed to achieve consistent cooking results. Of course, if you prefer to set you pressure keeping time for your own recipe, you can do so with the manual setting.

The following features are most notable to the one-button operation keys.

Intelligent Programming

These buttons are programmed intelligently based on thousands of experiments to achieve the best cooking results.

Take the “Rice” button as example. During rice cooking Instant Pot estimates the amount of rice and water by measuring the pre-heating time.  The pressure keeping duration is then varied based on this measurement. Detailed considerations are taken during every rice cooking stages of soaking, blanching, steaming and braising.  See Pete Vegas’ “Rice 101″ to learn more about the science of cooking rice.

Each function button can further be refined to vary food taste in the range of “rare”, “normal” and “well-done”.

Automatic Cooking

Instant Pot also provide convenience in fully automated cooking process, timing each cooking task and switch to keep-warm after cooking. Unlike conventional pressure cookers, you do not need to have a timer to manually monitor the cooking time.

Planning Meal with Delayed Cooking

Delayed cooking (up to 24 hours) can also be done with Instant Pot, allowing you to plan the meal ahead of time. Most importantly, you don’t have to stand around in the kitchen to watch over the cooker in operation. You are no longer tied to the kitchen to make the meal.

Needless to say, Instant Pot also reduces cooking time by up to 70%. It works wonders when you come home after work and have to get dinner on the table in a hurry.

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• Benefits

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By Instant Pot Staff, May 16, 2009

Instant Pot is one of greenest kitchen appliances, saving up to 70% electricity in comparable cooking to other appliances, e.g. oven, boiling pot + stove, steamer, etc. It is highly energy efficient thanks to the following features.

• As we know, food cooks rapidly under high temperature. Less cooking time means less energy consumed. Like other pressure cookers, Instant Pot reduces cooking time by up to 70%.
• Secondly, Instant Pot exterior housing is fully insulated. It’s cool to the touch in brief cooking and only lukewarm during long operations. Energy is concentrated on cooking the food. This makes it even more energy efficient than the conventional pressure cookers.
• Thirdly, Instant Pot’s intelligent monitoring system only heats the inner pot to maintain a certain pressure level. In a long duration cooking, heating is off nearly 40% of the cooking time.
• Fourthly, because Instant Pot is fully sealed during cooking, much less water is required for cooking (e.g. about 75% less in steaming). This essentially reduces the energy consumption in making a meal. As another benefit, your kitchen will not be steamy hot during the summer.

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