Rice Pot /Small containers such as plastic pudding containers can be used in a pressure cooker, if the containers (and any covering used) can withstand temperatures of 130 °C (266 °F) and are not placed directly on the interior base. The containers can be used for cooking foods that are prone to burning on the base of the pressure cooker. A lid for the container may be used if the lid allows some steam to come into contact with the food and the lid is securely fitted; an example is foil or greaseproof paper, pleated in the center and tied securely with string. Containers that are cracked or have otherwise sustained damage are not suitable. Cooking time is longer when using covered containers because the food is not in direct contact with the steam. Since non-metal containers are poorer heat conductors, the type of container material stated in the recipe cannot be substituted without affecting the outcome. For example, if the recipe time is calculated using a stainless steel container and a plastic container is used instead, the recipe will be undercooked, unless the cooking time is increased. Containers with thicker sides, e.g., oven-proof glass or ceramic containers, which are slower to conduct heat, will add about 10 minutes to the cooking time. Liquid can be added inside the container when pressure cooking foods such as rice, which need to absorb liquid in order to cook properly.
Not only is this steam energy transmitted quickly to food, it is also transmitted rapidly to any micro-organisms that are present, easily killing even the deadliest types that are able to survive at the boiling point. Because of this enhanced germ killing ability, a pressure cooker can be used as an effective sterilizer for jam pots, glass baby bottles, or for water while camping. In fact, the autoclave, used in hospitals to sterilize surgical instruments, is really just a more precise and technical version of the ordinary pressure cooker.
- Pressure cookers are considerably more expensive than conventional saucepans of the same size.
- The additional gasket (sealing ring) requires special care when cleaning (e.g., not washed with kitchen knives), unlike a standard lid for a saucepan.
- Food debris must be cleaned from the gasket after every use.
- The gasket/sealing ring needs replacing with a new one about once a year (or sooner if it is damaged e.g. a small split).
- A very dry gasket can make it difficult or impossible to close the lid. Smearing the gasket sparingly with vegetable oil alleviates this problem (using too much vegetable oil can make the gasket swell and prevent it sealing properly).
- A gasket that has lost its flexibility makes bringing the cooker up to pressure difficult as steam can escape before sufficient pressure is generated to provide an adequate seal; this is usually a sign that the gasket needs replacing with a new one. Oiling the gasket with vegetable oil may alleviate the problem temporarily, but a new gasket is often required.
- Pressure cooker manufacturers sell replacement gaskets and recommend their replacement at regular intervals e.g. annually.
- If the pressure cooker has not been used for a long time, the gasket and other rubber or silicone parts will dry out and will likely need replacing.
- In order to inspect the food, the pressure cooker needs to be opened, which halts the cooking process. With a conventional saucepan, this can be done in a matter of seconds by visually inspecting the food. As a result, accurate timing is essential for the recipe e.g. with an audible timer.
- A minimum quantity of liquid is required to create and maintain pressure, as indicated in the manufacturer’s instruction manual. More liquid is required for longer cooking times. This is not desirable for food requiring much less liquid, but recipes and books for pressure cookers take this into account.