Kevin Wagner, a frequent commenter on startcooking.com is today’s guest blogger. Thanks, Kevin, for all this valuable information!
Pressure Cookers – The Original Microwave
by Kevin Wagner.
A very useful tool for beginners to seasoned chefs and all points in between is the venerable pressure cooker. While they’re gaining popularity fast, there’s still some hesitation due to old stories that die hard about the dangers and drawbacks associated with their use. We’ll try to dispel some of those here.
Chef’s Design 9 Quart Pressure Cooker
A brief history
Back in the early part of the last century, pressure cookers were very popular because people didn’t have refrigeration or freezers, so canning was the order of the day if you needed or wanted to store food for any length of time. Pressure cookers were a good way to sterilize jars, as well as cook things thoroughly and in a reasonable length of time while preserving the valuable nutrients, texture, and flavor of the food.
During WWI, the depression, and WWII, shortages and rationing made manufacturing such things impractical, but they were still in high demand so people shared them. Once WWII was over, because demand was still strong, about 80 bajillion manufacturers in the late ’40s – early ’50s jumped into the pressure cooker game. They made a lot of bad units due to inexperience, the need for expediency, and a nation not so litigious as it is today. As you might expect, popularity dropped off. Handy is one thing, dysfunctional and/or lethal is something else. Also, at about that same time, refrigeration and freezing started to become common. Demand for pressure cookers began to drop off.
They’re becoming popular again because of energy concerns, the quality of the food you can make with them, and expediency. It’s nearly as fast as a microwave without all the downsides associated with that. But, liability insurance for making such things is through the roof, and all the safety features and structural overcompensation are expensive, so they’re not for the financially timid. A decent unit will run you anywhere from $45 to over $200, depending on size, features, and construction material (aluminum or stainless steel). On the plus side, all the good things about pressure cookers are still there, while the danger is gone. The pot I recently bought has 4 safeties built into it, so the chances of blowing my head off or burning myself are nearly non-existent. This ain’t your grandma’s pressure cooker.
How they work
So, why were they dangerous then and not now? To answer that, we have to know a little bit about how they work. It’s actually very simple. Water at sea level boils at 212°F. If you lower the pressure, say by going up a mountain or living in a high elevation area, the boiling point drops. It can get to a point where the water is boiling at such a low temperature that you can’t even cook with it.This is true of all liquids.
The opposite situation generally doesn’t occur naturally. That is, getting a higher pressure than at sea level in open air. Enter the pressure cooker. By enclosing and sealing the liquid in a pot, then boiling it, we create steam that raises the pressure in the pot, which at the same time raises the boiling point of the liquid. This phenomena can chase itself until the pressure is so high it forces an opening. Back in the old days, that sometimes meant bursting the pot if the pressure relief valve or regulator wasn’t working for some reason. Since the pots were made of steel or aluminum, it was a pretty violent thing. You not only got an explosion, you got super-heated fluids all over the place. But, generally cookers are limited to 15psi (pounds per square inch) or less, so the temperature stays below about 257°F.
Another thing that used to happen sometimes back then was someone would open the pot before the pressure had dropped down. In that case, you didn’t really get an explosion per se, but there was no telling where that lid was going to land. You also had super-heated steam blow out and catch you in the hands, arms, face, torso, etc. It was fast and it was a contact burn. There was no ducking it or wiping yourself off. You were burned, but good.
Why we aren’t so worried today
So, how do we prevent the pressure from getting explosively high or letting an active pot hurt us and ruin our day? Modern pots have a number of safety features built into them to prevent pressure build-up past safe limits (or at all), release over-pressures before they get dangerous, and mechanical interlocks prevent opening or closing them under the wrong circumstances. They’re very simple, highly effective, and difficult to bypass.
First, if everything isn’t just right, pressure won’t even build up. The sealing gasket has to be good, the safety releases have to be closed, the pressure regulator has to be set in place, and the interlocks have to be locked. Otherwise, it’s just a regular ol’ pot, albeit a little shinier than what the cavemen used.
Second, assuming we’ve done everything right and created some pressure, there’s a pressure regulator that’s designed to keep the pressure at some preset level. That can vary by design, but it’s always below 15psi. As a reference, the air in your car tires is probably around 32psi. If for some reason your regulator doesn’t work, there are other pressure releases. There’s always a valve in the lid set to open if the pressure goes above 15psi. Depending on design, there may be another one in the handle, which is part of the interlock system. There’ll be a similar one on the opposite side for the same reason. Also, the gasket may have a cutout it bears against that will pop open. In any event, you’re not going to build up too much pressure. Something is going to give, and it won’t be the pot or lid itself. You also won’t be able to open it until the pressure is back to atmospheric. So, we’re safe.
Why cook under pressure?
There are number of reasons, all of them good, but top of the list is always speed. You can make country-style pork ribs in 20 minutes flat, where a braise will cost you an hour and a half. Veggies generally only take a few minutes, sometimes even less. Because of the higher temperature and moist environment, you can use less costly cuts of meat and still have them be tender, saving you money. Speaking of saving, you use a lot less energy. Energy dissipation is lower, too, so you’re not going to heat up the whole house making dinner. You keep more of your food’s nutrients by not boiling them off over a long period of time, and what does cook off remains in the pot. The higher temperature also insures that any parasites or bacteria that may be on or in the food get killed off. Many recipes result in a single-pot meal, so there’s less clean up and clutter. The list goes on, but I think you get the idea. Pressure cookers are a Good Thing.
If you don’t have a pressure cooker now, I don’t think you’ll be sorry if you get one. If you currently have one of the older cookers, you may be better off replacing it. It’s not a good idea to give the old one away, either. They’re dangerous. The pot is fine to be used as a pot, but toss the lid so nobody’s tempted to pressurize the thing. Incidentally, there’s a pretty wide difference in price between online suppliers and locals, so shop smart.
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