Wednesday, July 27, 2011

The Pressure Cooker 101...Don't Be Afraid!

I've spent a good deal of time on this blog proclaiming the virtues of the pressure cooker but I've never taken the time to explain how it works.  I thought I'd take a moment and do a little "Pressure Cooker 101" in hopes that it'll convince more of you that it's not the dangerous gadget you thought it was and that it deserves a place in your kitchen.

Yeah, But Is it Really Safe??
In many ways, it's safer than your microwave...I'm serious.  Pressure cookers don't just explode of their own free will and I don't know of a way the cover can actually come flying off.  They have elaborate clamping/locking mechanisms that pretty much prevent such an accident...even in old models.  If you've heard Grandma's horror stories about redecorating the ceiling, what probably happened to her is the safety release plug blew.  Here's the deal..

All pressure cookers regulate the steam pressure inside the pot with the "pressure regulator" (ingenious name, don't you think?).  On the simplest models, this is a tube or "stem" in the cover with a hole in it.  You place a weighted "jiggler" over the stem that's calibrated such that if the pressure goes over 15psi, the jiggler will tilt to the side and let some steam out.  This constant rocking motion or "jiggling" makes sure the pressure inside stays constant during cooking and that the excess steam is vented.  In fancier models, the mechanism is often spring-loaded, but the concept is the same.

The problem usually comes from the backup system.  Manufacturers want to make sure that if the main regulator should fail that something else will allow the steam to escape in a relatively safe way.  In older models, this was a rubber plug in the top of the lid.  In the event that the unit goes way over the 15psi normal operating pressure, the plug will fly out of the top, venting steam and food straight upward.  The advantage is that nothing flies outwards and hurts the cook or anyone else in the room.  The disadvantage, of course, is that food hits the ceiling and viola--you're redecorating the kitchen.

The good news is that many newer models have backup vents that vent downward towards the stove instead of out or up.  Others have spring-loaded backup vents that will vent steam but very little food.  Even if you do have a plug-style vent, you need not fear it blowing as long as you keep the pot in good repair, replace the plug now and then, and don't just walk away from the unit and forget it on the stove.  In other words, common sense rules.

Now that that's out of the way, let's get cooking...

The Basic Rules
There are a few basic rules that apply to all pressure cookers:
  • Always follow the "Two-Thirds" rule, meaning you should never fill the pot more than 2/3 of the way full with food.  The pot needs air space to build-up steam pressure.  If you fill the pot to the brim, it'll never build-up enough pressure to cook and you'll just end-up with burnt food on the bottom and raw food on the top.  You can also end-up with food coming out of the primary vent and that's not good or safe either.
  • Read your instruction manual!  Every pot works slightly differently and you must know how to work your pot in order to use it safely.  Know how the locking mechanism works.  Know how the primary and secondary vent systems work and how to tell when it's "at full pressure."  Know how to use the "rapid" pressure release feature if one exists (more on this later).  Most importantly, know how to maintain your pot and how to tell when parts need replacing.
  • Make sure there's at least a cup of water in the pot beyond what you expect the food to absorb (unless you're following a tested recipe that says otherwise).  Pressure cookers work on steam.  That means that some water will be used to build-up and keep pressure and a *lot* of it will be vented during the cooking and pressure release process.  More water is always safer.
  • Never ever ever try to open a pot while it's under pressure.  If you can open a rapid release valve or remove a jiggler, do that carefully and slowly first and leave it open for a minute or two before attempting to open the lid.
Let's Get Cooking!

This is a very basic outline of how cooking works in a pressure cooker.  It's for illustrative purposes only.  It's probably best if you start-out following tested recipes since you won't have a feel for the abbreviated cooking times until you've done quite a bit of cooking in the pot.  Even I still consult cookbooks before I begin.

1) If you're cooking meat, most recipes tell you to brown the meat in the bottom of the pot with some fat first.  This is purely for flavor development as pressure cooking is a wet cooking method.  The same goes for sautéing vegetables.

2) Put the rest of the ingredients in the pot. Pour-in the water or liquid that will be used to generate steam and, in some cases, add flavor to the food.

3) Cover the pot and attach the regulator (if needed) and heat the pot on high heat until it comes up to full pressure.  Consult your user manual to find out how to tell when it's at full pressure.  For jiggler models, it's when the jiggler begins rocking quickly and emitting steam.

4) Once it's up to pressure, reduce the heat to low or medium low and start the timing for the recipe.  This is probably the only tricky part and you'll get the hang of it once you get to know your pot.  The objective is to keep the stove at the lowest temperature necessary to keep the pot at full pressure.  For jiggler models, this is usually a gentle rocking or spinning motion of the jiggler with minimal steam escaping.  If the jiggler stops moving, the pressure has gone too low and the burner heat needs to be increased a little.

5) Once the time is up, turn the burner off and gently remove the pot from the heat.  If your recipe calls for a "natural release," simply walk away and allow the pressure to go down on its own.  This may take up to 15 or 20 minutes, depending on the food.  Typically, a natural release is used for meats and large pieces of food and it's important to do because the release counts as part of the cooking time (i.e. the food finishes cooking during the cool-down).

Other recipes, usually those for vegetables and grains, will call for a "Rapid Release," meaning that you are to release the steam right away so as to not overcook the food.  Newer pots often have rapid release mechanisms and you should consult your user manual to find out how to safely operate it.  If you don't have one, you can carefully move the pot to the sink and run cold water over it.  The cold water will condense the steam inside of the pot and reduce the pressure quickly.

Some pots have a button or indicator that will tell you when pressure is down.  For jiggler models, you can gently tap the plastic top of the jiggler with a long utensil such as a wooden spoon to see if steam escapes.  Just keep your hands away from the steam!

6) Once the pressure is down, you can safely remove the jiggler (if you have one) and open the pot.  A good deal of steam will still escape, so open it carefully and away from you as you would any hot steamy pot.

That's it!  That's really all it takes to use a pressure cooker.

What Are the Benefits?

There are literally dozens of benefits to using a pressure cooker and I've mentioned most of them in the past.  However, some things are worth repeating.
  • Reduced Cooking Time - Pressure cookers can reduce cooking time by up to two-thirds.  Imagine pot roasts, beef stew, and homemade stock in 45 minutes instead of hours.  Corn takes just 6 minutes, as does white rice.  Brown rice takes just 20-25 minutes instead of 45.
  • Energy Savings - Because the majority of the cooking takes place on low heat, you use much less energy than any other method, including the microwave.
  • One-Pot Cooking - Pressure cookers excel at one-pot meals like stews, braises, etc.
  • More Vitamins - Because the food cooks for less time and because it's cooking via steam, most pressure cooker dishes retain more vitamins and minerals than when they're cooked in the traditional way.
I hope this convinces more of you to give pressure cooking a try.  If you don't want to invest in a pot, borrow one from a friend or relative.  I can almost guarantee Mom has one kicking around that she rarely uses.  Just make sure the rubber seals and the safety plug are in good shape and give it a try.  I promise you'll love it.

1 comment:

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