Tuesday, June 23, 2009

Thrifty Cooking: Dinner...Under Pressure

If there's one piece of specialized equipment I'd recommend that everyone invest in, it's a pressure cooker. If there's one piece of kitchen equipment most people are absolutely terrified of, it's the pressure cooker. After trying one out myself, I'm not sure why. I'm way more afraid of my mandolin slicer, which has tried to take off my finger tips on more than one occasion and almost succeeded once.

The Fear of Blowouts
The problem with pressure cookers is that everyone has heard of someone, who knows someone, who's great-grandmother blew her cooker sky-high and re-decorated the kitchen ceiling with beef stew. If you actually look at Great Grandma's pressure cooker, you'll notice a small rubber plug in the cover of it. That little rubber plug, known as the "safety release valve," is the source of Granny's warning to you. The plug is designed to pop-out if the pressure inside gets to be too much and it works as designed. The real problem here is really just poor design. As anyone who's ever opened shaken champagne or a bottle of soda will know, the contents of the pot will come out with it--with a vengeance. Since the hole is in the top, the food is going to go up and redecorate the ceiling.

That's why *most* manufacturers have done away with the rubber plug in favor of more high-tech devices. My pressure cooker, for example, has a piston-style safety release. If the cooker should gain too much pressure, the pin would move up and steam would vent out sideways like a steam-train whistle, hopefully without food in tow. Some of the more expensive pots have "ear" style closures with springs and a claim that, in the event of a pressure build-up, the lid would lift slightly and the steam and food would move downwards onto the stove, which is much easier to clean than the ceiling.

All safety features aside, if you use your pressure cooker correctly and take good care of it, you'll never even need the safety release valve. I have NEVER had it kick-in. In the grand scheme of things, a pressure cooker is not really under a ridiculous amount of pressure. It's roughly half the pressure of the tires in your car and those are made of rubber, not metal, so they're way more likely to burst. All you really need to safely use a pressure cooker are these three rules:

1) Never fill the cooker more than 2/3 full with food or liquid (or to the fill line if you have one).
2) Always make sure the steam vents are clear of gunk (yes, that's a technical term).
3) Always read your pressure cooker's instruction booklet and know how your individual model works.

That's it. Do those three things, and I guarantee you'll never have a blowout.

Why use a pressure cooker?
Here are a few reasons:
1) A pressure cooker can reduce the time required to cook some foods by up to three-quarters. That means long-cooking foods like braises (pot roast, pulled pork) or stews can be had on a weeknight in less than an hour.
2) Pressure cooking is a "green" cooking method as it uses much less gas or electricity. Food takes 3/4 less time to cook and maintaining pressure, once achieved, only requires a "simmer" temperature setting on your stove as opposed to medium-high.
3) Homemade chicken stock in 45 minutes. 'Nuff said.
4) Pressure cooking is essentially steaming. We all know that steaming keeps nutrients in the food much better than any other "wet" cooking method.
5) Pasta AND sauce in one pot in about 15 minutes (more on this later).

What's going on in there?
Have you ever read a recipe where there are alternative cooking times for those who live at higher elevations such as in the mountains? The reason for this is that mountainous regions have lower atmospheric pressure than sea level areas and the boiling point of water (the point at which water turns into steam) is reduced when there is less pressure. Since water boils at a lower temperature in the mountains, it's necessary to have shorter cooking times so you don't cook all the water out of your food and end-up with dry baked goods.

This same concept is what makes a pressure cooker work, except in reverse. A pressure cooker has a locking lid that traps steam, increasing the pressure inside the pot. This causes the boiling point of water to increase from 212 degrees to 240 degrees or higher. Since we can get water (or anything, for that matter) to a higher temperature inside this environment, it cooks faster than it would in an open pot. Also, less heat energy is lost in the form of steam, so you need less energy to cook the food. Once under pressure, medium-low heat is all it takes to keep it there.

That's why we can pull-off chicken stock in 45 minutes. That's why we can cook brown rice in 25 minutes instead of 45-60. That's why ears of corn take just 6 minutes and are crisp and crunchy to the bite.

Regulating the Pressure
Some expensive models or models designed for pressure canning have pressure dials attached to the lid that show the pressure inside the pot. Others have sophisticated spring-loaded mechanisms to regulate the pressure. Most models, however, come with a standard "jiggler" that fits over a vent pipe in the lid. The jiggler is a weight that specifically calibrated so that it tips enough to let steam out only once the pressure inside the pot tries to exceed 15psi (pounds per square inch). The rocking motion is the jiggler letting some steam out to keep the pressure at or below 15psi.

For jiggler models, once your pot comes up to full pressure, the jiggler starts rocking rapidly. At this point, you can lower the temperature of the burner to medium-low or simmer. Ideally, you want to choose a temperature that just barely keeps the jiggler rocking. As long as the jiggler is rocking, you know you're at 15psi and your food is cooking away at warp speed.

Which recipes work best?
The best recipes for a pressure cooker are braises (pot roast, short ribs, braised chicken, etc.), anything steamed (fish, veggies, etc.), or soups and stews that benefit from long simmering times (stew, chili, etc.). Rice also cooks very well and can often be combined with meat or fish and veggies for a one-pot meal. Invest in a decent pressure cooking cookbook. My favorite is: 125 Best Pressure Cooker Recipes by Cinda Chavich. Once you get used to the recipes in the book, try modifying your own favorite recipes. Pick the closest recipe in the book to your recipe an use the liquid volume and timing from that recipe. There's also a chart in the front of the book for cooking times for common base ingredients.

Okay, how about that pasta?
One of my favorite tricks with the pressure cooker is this pasta recipe I found while perusing books one day. I've only ever seen one similar recipe online, so this is pretty unique. You cook the pasta WITH the sauce and a bit of extra water and end-up with perfectly done pasta and sauce that's just the right consistency.

Pressure Cooker Pasta With Sauce (All In One Pot)
1 clove garlic (whole)
1 small onion chopped fine
1/2 pound of rigatoni (or penne, or similar chunky pasta)
2 cups pasta sauce (any jarred sauce will do)
1/2 cup water
1 tablespoon balsamic vinegar
pinch of red pepper flakes (or more if you like heat)
salt and pepper to taste
basil and oregano to taste

Put everything into the pressure cooker and stir. Bring to full pressure (15 psi) and cook at full pressure for 12 minutes. Use the rapid-release method, stir, and serve.

I've also added chunks of sausage, chunks of hamburg, chicken, and red or green bell peppers to this with great success.

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