Food Science: Pressure Cooking

imagesHappy Monday, everyone!  Today we’re gonna do some learnin’.   As I promised last week in the Beef Bourguignonne post, I am going to try to break down the science behind pressure cooking a little bit.   It’s a fairly simple theory and procedure, and the benefits of using this cooking method are pretty vast.   It’s one of my favorite ways to cook.

So what exactly is a pressure cooker?  Basically, you’ve got a sealed vessel, or the cooker itself.  It has an interior chamber, usually stainless steel or nonstick material, if you have an electric pressure cooker like I do.   The outer pan has handles and then there’s the lid, which is where the magic happens.  The lid has a gasket that seals in the pressure, a mechanism that clicks the lid shut, a steam vent, and a pressure indicator, plus multiple safety features.   That leads me to an important announcement.

This image, or one like it, is probably seared onto your brain:

explodingpressurecooker

Nowadays, your rice won’t meet Holly Golightly’s unhappy fate.  Pressure cookers from that era were most likely made during the pressure cooking bonanza after the Second World War.  There was a massive explosion (get it…eh?) in the popularity of pressure cookers, and unfortunately the bulk of the manufacturers were how you say…shady.  They didn’t add safety features, used thin metals, and made them on the cheap, subjecting the public to scenes that played out like the one above.   Dangerous stuff, especially if you tend to hover over your food while it cooks.  Luckily, a survival of the fittest scenario played out:  the shady guys got run out of business due to declining sales, and the good guys kept on making and improving on their models.  Which brings us to today.  Current pressure cookers have at least a triple safety feature system set up.  They are perfectly safe to use as long as you follow the instructions.  Upon researching this, I read a couple of articles of pressure cooking mayhem.  Honestly, either the lids weren’t secure, or in the case of the ill fated 79 year old woman, she was most likely using her pressure cooker from the good ol’ days.   Throw out your old appliances, people.  Now we can choose from lots of good manufacturers and there are both stovetop and electric options.  I like the electric ones because you can sear, simmer, keep warm, choose from high or low pressure, and not have to worry about regulating the pressure on the cooktop.   Just set it and walk away.  Just be sure, no matter what kind you use, to exercise caution when releasing the steam.   A thick kitchen towel does the trick.

pressure-cooker-diagramBack to the cooking!  So pressure cooking involved putting food inside the pot with a smaller amount of water or liquid than one would normally use if you were, say boiling.  Remember my beef bourguignonne?  Normally, that would take 5-6 cups of liquid total.   In the pressure cooker, it was more like 1.5 to 2 cups.  When the lid is secured and the heat is applied, the water boils, and steam and pressure build inside the pot.  The building pressure heats the food through water vapor, which gets much hotter inside than one is able to achieve just  by boiling or oven cooking.  That water vapor, or saturated steam, just pummels the food inside with liquid and it allows you to cut the cooking time by huge increments.   Take, for example, whole, unsoaked pinto beans.   Normally, one would need to soak the beans in water overnight.  Then they would need to be boiled for a several hours.  In a pressure cooker, you can put the unsoaked beans in for 40 minutes and presto, they’re done.  (With beans, a 3 cups of water to 1 cup of beans ratio is a good one to keep in mind.)  Other things I’ve quickly cooked in the pressure cooker:  6 minute risotto, 55 minute short ribs, 5 minute mashed potatoes, 5 minute tomato soup, 5 minute white rice…the list goes on.

The last bit I wanted to mention today was the nutritional aspect of pressure cooking.   You might be inclined to believe that this method would squelch any nutrients right out of the food.   But no!  You actually maintain more of the vitamins and minerals by pressure cooking.   It makes sense, when you think about it.   All of the food, liquid, steam, etc, are tightly contained within the cooker.  So here’s the catch with veggies:  the bulk of the nutrients are in the cooking water.  You can save it and use it as a stock, if it is cooled correctly.   Or consume it with your veggies.   With grains and legumes, the pressure cooker actually makes them more digestible, which means you get more nutrition from them.  Same with red meats: fat is destroyed, but iron is maintained.  The best argument for pressure cooking, however, is that you are avoiding chemicals and carcinogens presented by other cooking methods.     And that’s always a good thing!

For more information, check out these websites:

http://www.hippressurecooking.com  –  amazing recipes, great reviews, and tons of great info.

Conversion Times for Pressure Cooking:  http://fastcooking.ca/pressure_cookers/cooking_times_pressure_cooker.php

http://missvickie.com/  – lots of great recipes!

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2 thoughts on “Food Science: Pressure Cooking

  1. sonomaist January 11, 2013 at 6:14 PM Reply

    Too funny! I have that exact image in my head and I never even saw the film. I’m the same way when people make balloon animals…Difference is, pressure cookers serve an actual purpose…Like getting Julia Child inspired beef dishes into my tummy quickly. I’ll have to rethink this…

  2. […] George Foreman grill you got freshman year.  You know what I’m talking about.   Finally, we all know I love pressure cookers.  Go for electric as they are much easier to use, and can significantly cut down the amount of time […]

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