A pressure cooker is an indispensable gadget for anyone with even a small amount of kitchen savvy. When it's time to add a pressure cooker to your kitchen arsenal, the main decision you will have to make is between a high-pressure cooker or a low-pressure cooker. Each pressure cooker is intended for the same general purpose, but the two items are distinct in their specifications.
High- and low-pressure cookers are designed for the same purpose: to cook food quickly. Pressure cooking reduces the cooking time of food items by regulating the release of steam moisture from a sealed pot. Increased pressure also increases the boiling point of water, so the water is able to reach higher temperatures and decrease cooking time. Pressure cookers are preferred methods of cooking for people who work in fast-paced commercial kitchens, and for people who can their own fruits and jams.
The signature difference between high-pressure and low-pressure cookers is the highest degree of pressure permitted in the cooker before the release valve will let out excess steam. High-pressure cookers operate at or above 15 pounds of pressure per square inch, or psi. Low-pressure cookers rarely handle pressure capacities over 10 psi, with some low-pressure cookers operating as low as 5 psi.
High-pressure cookers must be designed to handle high psi levels, and therefore they must be made of heavier materials such as stainless steel. Low-pressure cookers don't require the same strength and are often made of less expensive materials such as aluminum. Because of the higher material cost, high- pressure cookers tend to be more expensive than low-pressure cookers of the same size.
The higher the pressure, the faster the cooking time. High-pressure cookers thoroughly cook food significantly faster than low-pressure cookers. Low-pressure cookers still cook foods faster than a conventional pan would, but they cannot cook food as quickly as a high-pressure cooker.
Though low-pressure cookers do not cook food as quickly as high-pressure cookers, some people may feel more comfortable working with a low-pressure cooker. High-pressure cookers may be intimidating for novice chefs; chefs must carefully follow the manufacturer instructions for use because such high pressure could cause an explosion if not properly executed. Low-pressure cookers do not carry the same high level of explosion risk, and they tend to be quieter and less intimidating while in use. Not all foods are appropriate for high-pressure cooking; delicate vegetable such as spinach fare much better in a low-pressure cooker than in a high-pressure cooker, while meats and hardier vegetables cook quickly and easily in high-pressure cookers.