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All about Electric Pressure Cookers

What is an electric Pressure Cooker, Operation, Advantages/Disadvantages, Recommended cookers, Recipes

WHAT IS AN ELECTRIC PRESSURE COOKER

Electric Pressure Cookers are known as 3rd generation Pressure Cookers (PC). A typical Electric PC consists of 3 basic components

1. Removable COOKING POT

2. LID: The lids have a built in pin-lock mechanism to prevent opening the lid under pressure. The lid also serves as a handle. It has three basic parts:

- Float Valve: Under extreme pressure/temperature condition, the valve is permanently destroyed releasing the pressure

- Sealing Gasket: it forms air-tight chamber between the lid and the Cooking Pot

- Pressure Release Knob. It allows to manually VENT/SEAL steam. It also includes an anti-block shield.

3. Housing has a control panel with fuzzy logic, heating element and pressure/temperature sensors. The COOKING POT sits on the heating element. Underneath the heating element there is a pressure/temperature sensors. The functionality of the fuzzy logic varies from model to model. As a minimum, it is used to enter Cooking Time.

Types of Electric Pressure Cookers

The first patent for Electric PC was filed in 1991 by Yong-Guang Wang (Chinese scientist). The patent is owned by Midea (China), world's largest manufacturer of electric pressure cookers. Functionality has evolved over past 3 decades, into three generations of Electric PC

1st Generation (Rotary Timer)

PC is equipped with a pressure sensor, temperature sensor, and a rotary timer. Operation is very simple

1. User adds all the ingredients to the Cooking Pot, Close the lid, Turn Pressure Release Knob to SEAL position and set Timer

2. The fuzzy logic turns on the heating element; till either the pressure or the temperature has reached a threshold value, the heating element is turned off and the rotary timer is activated to count-down time. During count-down the heating element is turned on/off to maintain the pressure.

3. After the timer has elapsed, the fuzzy logic controls the heating element at a lower temperature threshold to keep food WARM

4. When the lid is off, User can use the heating element as a hot plate by setting the Timer to an arbitrary value. This allows the user to sauté/brown/simmer.

Masses in USA were introduced to 1st Generation PC by HSN (Home Shopping Network) to sell Wolfgang Puck, 7 Quart Pressure Cooker Model (Model BPCRM040)

2nd Generation (Digital Time Display)

The fuzzy logic was enhanced to digitize the pressure sensor and display the 'cooking-time' count-down. It also allowed to enter Delayed Time to start cooking. Other features were added:

1. Two selectable Operating Pressures HIGH for cooking most of the foods, and LOW to cook fish

2. Preset Cooking Time for convenience examples: Rice, Meat, Vegetables

3. Audio warning after the Cooking Time has elapsed

4. Selectable open-lid hot-plate functions: Brown (High), Sauté (Medium), Simmer (Low)

5. Selectable open-STEAM VENT operation to emulate Slow Cooker

1st Generation PC were replaced with 2nd generation PC in a matter of few months. 2nd Generation PC are now most common in USA. The Electric PC sold in USA are made in Asia primarily China. No Electric PC are made in USA or Europe. Most of the products are marketed by HSN, QVC, and Amazon. Examples are: Wolfgang Puck (Bistro), Elite, Emeril (T-Fal), Cuisineart,  Cook's Essentials, Montel Williams (Living Well), Chris Freytag (West Bend), Deni, Fagor,  Instant Pot, All-Clad, Nesco, Imusa

3rd Generation (Smart Cooker)

The fuzzy logic is re-designed around a microprocessor to perform complex tasks based on more accurate temperature and pressure input. The major improvement is a sequential task called 'Multigrain Programming'. It allows grain to be presoaked in warm water (86°F) for 40 minutes, and then pressure cook for a User defined duration. This can be very useful in making brown-rice and legumes. The only 3rd Generation PC sold in US is 'Instant Pot' Model IP-LUX60

BASIC OPERATION OF ELECTRIC PRESSURE COOKER

STEP 1: Meats/Chicken may be browned and set aside. Curries would require Masala sauté of onions/garlic/ginger/curry spice mix. Gather all ingredients for a given recipe and add to the COOKING POT. Make sure you have at least one cup of liquid/water in the recipe. Liquid is essential to create steam under pressure to rapidly cook food. If there is not enough liquid to generate steam, fuzzy logic will result in Error.

STEP 2: Close the lid and secure in Lock position. Turn the Pressure Release Knob to SEAL/CLOSE position.

STEP 3: Set Operating pressure. Most of the cooking is done at HIGH, few recipes require LOW. If this is not a selectable function on your cooker, you may assume it is HIGH.

STEP 4: Enter COOKING TIME. Many cookers have selectable functions such as MEAT, VEG, SOUP, RICE, these functions are basically pre-set cooking times.

STEP 5: Press START. The heat will create steam and generate pressure. As soon as the pressure is detected, a locking pin engages and prevents the lid from opening. Most of the pressure cookers don't publish this minimum pressure when the locking pin is engaged. Normally, it is near 0.7 psi.

The heating element remains on till the unit has reached the OPERATING PRESSURE set in Step 3. As soon as the OPERATING PRESSURE is reached, fuzzy logic starts to count down COOKING TIME set in Step 4, and control the Heating element to maintain OPERATING PRESSURE.

After the COOKING TIME has elapsed, the cooker automatically switches to 'KEEP WARM' mode and turns off the heating element to let the pressure dissipate. The temperature drops down to about 150°F, the heating element is turned on and off to maintain this 'WARM' temperature. It takes about 15 to 20 minutes to fully dissipate the pressure.

STEP 6: After the pressure is dissipated, you may un-lock the lid. To dissipate pressure quickly, turn the Pressure Release Knob to OPEN/VENT position and let the steam escape completely. Un-lock and open the lid

OPERATING PRESSURE

Operating Pressure for traditional pressure cookers is 15 psi. Electric PC do not follow any standard. They operate at lower psi, don't publish the operating pressure data, use subjective terms such as 'HIGH',  'MEDIUM' or 'LOW' instead. Most of the Electric PC operate at default psi of 11.6 psi (80 kPa), and may be selected to a lower 6 psi (40 kPa). I found only one PC that published an acceptable data: Deni Pressure Cooker (Model 9760) High (15 psi), Medium (7.5 psi), Low (2.5psi).

ELECTRIC versus STOVE-TOP PRESSURE COOKERS

Disadvantages

1. Stove-top PC operate at 15 psi. Electric PC operate at lower psi. Lower psi means longer cooking time, and less efficient extraction of meat flavors. User has to convert cooking time for Stove Top PC to Electric PC.

2. For quick pressure release, you can move the Stove-Top PC sink under running cold water and release the pressure within 20 seconds. For Electric PC, turn the Pressure Release Knob to 'VENT/OPEN' position, it may take nearly 2 minutes.

3. Stove-top PC are more reliable (10 year warranty) than Electric PC (One year warranty). The service parts of the stove-top pressure cookers are readily available in USA.

Advantages

1. Fuzzy logic is used to control heating element with time and temperature. The biggest advantage is that cooking time automatically starts after reaching the operating pressure, after the cooking timer has elapsed, the cooker automatically switches to WARM mode and start to dissipate pressure. Read the manual, the keep WARM time may vary from 4 to 10 hours.

2. You can program most of the Electric PC for Delayed Cooking. It is a nice feature for unattended operation so meal is ready when you are ready. Read the manual, some PC use it as delayed starting time, while others use it as delayed end of cooking time.

3. Electric PC release very little steam during cooking, making it less noisy than the Stove-Top PC. It also means that liquid volume must be adjusted when converting Stove-Top PC recipes.

HOW TO CHOOSE AN ELECTRIC PRESSURE COOKER

I want to use PC as a pressure cooker. Some of the features are interesting but not relevant such as: Delay Time, Steamer, Slow Cooker. As a matter of fact improper use of Delay time can result in spoiled meat. I have listed 10 attributes, a User may consider when buying an Electric PC

1. Cooking Pot. It should be 6 to 8 quarts cooking pot should be made of 18/10 stainless steel with 3-ply bottom (Aluminum sandwich) for even heat distribution

2. Efficient Quick Pressure Release

3. Accessories: Glass lid with steam vent, Stainless steel Trivet Steamer, Extra Seal Gasket (Sooner or Later, you will need a seal gasket)

4. Operating Pressure: Two selectable operating pressures High (15 psi), Low (7.5 psi)

5. Visual pressure indicator.

6. Digital display of Cooking Time count-down. Rotary Timer is not acceptable for accuracy

7. Audio warning after the Cooking Time has elapsed

8. Selectable open-lid hot-plate functions: Brown (High), Sauté (Medium), Simmer (Low)

9. Long KEEP WARM time beyond 4 hours is interesting but not necessary. Long WARM times can actually destroy food texture.

10. I like one function provided in 3rd Generation PC (pre-soak for 50 minutes in warm water before starting to cook). This can be easily provided with 2nd Generation PC.

RECOMMENDED ELECTRIC PRESSURE COOKERS

Most affordable and simplest to use: Wolfgang Puck, 4 in 1 - 7 Quart Pressure Cooker

Most expensive, High end: All-Clad®. Unfortunately, the OPERATING PRESSURE is below 15 psi and the capacity is only 4 Quarts

High End: Deni Pressure Cooker (Model 9760) High (15 psi), Medium (7.5 psi), Low (2.5 psi). Unfortunately COOKING POT is not made of Stainless Steel

3rd Generation PC sold in US is 'Instant Pot' Model IP-LUX60, It has 6 quart stainless steel pot, but operates at 11.6 psi only. For an average User, too much of a functionality to remember and get used to.

CONVERTING RECIPES 1st generation PC to Electric PC

1. Reduce liquid volume

1st generation PC employs a weight that covers the steam vent. After the cooker reaches15psi, the weight jiggles to vent steam and maintain 15 psi. Depending on the cooking time and the heat of the stove, you can lose about ¾ cups of water in 5 minutes through escaping steam. There is very little loss of fluid volume with Electric PC. As a rule of thumb, when converting 1st generation PC recipes, cut the liquid volume by about 40%.

2. Cooking Time at Operating Pressure

1st generation PC operate at 15 psi. The Electric PC operate at lower psi; lower the psi, higher is the cooking time. If the operating pressure is x% lower, increase the cooking time by x%. 12 psi is 20% (15psi-12psi=3psi, 3/15*100=20%) lower than 15psi, so increase the cooking time by 20%. If the cooking time at 15psi is 50 minutes, increase the time by 10 minutes (20% of 50 is 10) to 60 minutes. Similarly, 7.5 psi is 50% lower than 15 psi, and the cooking time must be increased by 50%.

3. Heating time

Food starts to cook during heating phase before it reaches operating pressure. It takes longer to reach 15psi than 12 psi. This is not significant, and may be offset by adding a fraction of a minute to the cooking time under operating pressure.

4. Pressure Release Time

After cooking time under pressure has elapsed, food continues to cook as the pressures starts to dissipate. It can be a very significant factor, some recipes even call out for quick pressure release. For natural pressure dissipation, 15 psi cookers take about 5 minutes longer than 12.5 psi cookers. This calculation is beyond the scope of discussion here. For natural pressure dissipation recipes, increase pressure cooking time by about 1 minute at 12.5 psi over 15psi cookers

RECIPES FOR ELECTRIC PRESSURE COOKERS