Knowing how to release the pressure in a pressure cooker is important. It can be done in two ways, the first of which is to allow the steam to release naturally by simply removing the pressure cooker from the heat source at the end of the cooking time. It should then be left for about 10–15 minutes before opening to cool down, which releases the pressure naturally. Using this method is particularly important when cooking meat as the fibres will relax as a result of the final gentle pressure and maximise the tenderness (it’s equivalent to allowing the meat to rest after it’s been cooked on the stovetop or in the oven). Allowing the pressure to release naturally is also important for dishes such as risotto because the rice can then continue to cook slowly, absorbing all the liquid and flavours in the process.
The second way of releasing pressure is the quick release method, which is accomplished by carefully placing the pressure cooker in the sink and running cold water over the lid taking care that none gets into the valves. The pressure will be released quickly and when the pressure valve goes down it can be safely opened.
Many pressure cookers also have a pressure release button which, when depressed, will allow the steam to escape quickly (your user’s manual will have details).
Safety Note: Steam can cause nasty burns so always release the steam and open the lid away from yourself or anybody in the vicinity. Excess steam and condensation can also cause damage to some surfaces in the kitchen so take care that you open the pressure cooker well away from anything that could be damaged.
Most pressure cookers will operate at the same rate, but there could be other variables that may alter cooking times(eg. The size and freshness of ingredients, particularly vegetables). It pays to remember that overcooking can sometimes be a problem and for this reason a timer is an invaluable aid as a minute or two can make a real difference. Always set the timer from the point just after the pressure indicator has risen with a resulting gentle hiss of steam. Reduce the heat to maintain this pressure – and then set the timer.
If you are unsure about the cooking time for a particular dish cook it for a shorter time than you think it will need and then check progress by using the quick release method to check. It’s easy enough to bring it back to pressure again if whatever you are cooking needs more time. Cooking times in the book are based on the ingredient that takes the longest to cook so it can happen that when everything is put in at the same time some vegetables can get overcooked. To avoid this happening, try cutting the faster-cooking vegetables into larger chunks so they take longer to cook or put them in later in the cooking process. For example, subtract their cooking time (ie take 5 minutes from the total cooking time and using the quick release method open the cooker and add the vegetables in at this stage) . Return the cooker to the heat and bring up to pressure again and finish the last 5 minutes of cooking time when it comes up to pressure again.
It’s so easy to cook vegetables in a pressure cooker. An added bonus is that they retain their flavour as well as all those nutrients that are usually lost through boiling in large quantities of water. And it goes without saying cooking them this way saves time and power.
For best results place vegetables in a steamer basket and pour in 1–2 cups of water. Cook starchy vegetables (eg potatoes) on high pressure and more delicate or leafy vegetables on low pressure. Use the quick release method to avoid overcooking.
For cooking times for individual vegetables check the manual that came with your pressure cooker. Most contain charts to assist with cooking times. Alternatively, use one-third of your usual cooking time as a guide or check pressure cooking times. Note that the size of vegetable and its state of freshness or otherwise can affect cooking times.
A pressure cooker works the way it does because it requires enough liquid to produce steam and, unlike boiling or baking, the steam stays inside the pressure cooker and doesn’t evaporate. The end result is a moist flavourful liquid that can be used to make a delicious sauce or gravy and which can be thickened easily and quickly by mixing 1–2 teaspoons of cornflour (cornstarch) with enough cold water to make a smooth paste. Stir the paste into the gently simmering liquid in the pressure cooker at the end of the cooking time. Stir for a few minutes until the sauce thickened to the desired consistency. (Repeat if a thicker sauce is required.)
Alternatively, the sauce can be reduced at the end of the cooking time by removing the lid and allowing the sauce to simmer gently, while you stir it until the desired thickness is achieved.
Some recipes require a heatproof dish to be lowered into the pressure cooker; a process that is made much easier by the use of a sling. Make a sling by cutting a piece of tinfoil long enough to sit under the dish and come up either side to the top of the pressure cooker. Fold the tinfoil in half and half again lengthways so it will be strong enough to support the weight of the dish. A foil sling like this can be reused a number of times. You can also use a tea towel or cloth; Simply fold it lengthways into thirds. Use the sling to lower the dish into the pressure cooker, then fold over the ends over the top of the dish while it cooks. At the end of the cooking time, ensure the tea towel is cooled enough to handle before lifting it out.
It’s easy enough to start adapting your own recipes for the pressure cooker. Just remember that liquid is important – there needs to be enough to create the necessary steam. As for what kind of liquid, it can be water, stock, wine, fruit or vegetable juice – it depends on what you’re cooking. Allow about half a cup of liquid for dishes that require 15 minutes of cooking and 1–2 cups for longer times.
I suggest that when you want to adapt one of your own recipes, see if you can find a similar recipe in Lisa’s pressure cooker book to use as a guide. Failing that, reduce the normal cooking time to one-third, eg if a dish normally takes 30 minutes to cook, try it in the pressure cooker on high pressure for 10 minutes. If you are unsure, it’s better to cook it for a few minutes less and then test it. If it is not quite cooked bring the pan up to pressure again and cook for a few minutes extra before checking again. Keep a note of how long it took for next time.