Pressure cookers exploded (sorry) onto the culinary scene in the United States during World War II when, as the masterful Lorna Sass writes in Pressure Perfect: Two Hour Taste in Twenty Minutes Using Your Pressure Cooker, “Rosie the Riveter came home from her shift and had to make dinner for the kids.” Cooking food in one-third the time is just as powerful a lure for today’s overscheduled cooks, but the modern “second-generation” models now available are a far cry from Rosie’s jiggle-top pressure cooker, which hissed, rattled, and chugga-chugged in a thoroughly sinister manner when pressure was reached—a duck-and-cover appliance if there ever was one.
The new cookers are more expensive but well worth it: They’re quiet, are virtually foolproof, and have multiple safety features. They’re versatile too. The design of the spring-valve pressure regulator prevents the valve from clogging, so you can easily whip up a batch of a food that foams when it cooks—beans or whole grains, for instance—in no time. Another plus is a stovetop quick-release option, so you don’t have to transfer a heavy, hot pot to the kitchen sink and release the pressure under cold running water.
A pressure cooker, in fact, is one of those pieces of kitchen equipment that will change your life—especially if you love the idea of long-simmered stews and other dishes but don’t have the time to tend them or deal with the plan-ahead aspect that slow cooker recipes entail. Having one at the ready means that chili, jambalaya, risotto, a meat or vegetable curry, a whole-grain pilaf, lamb stew, homemade chicken broth, even corned beef with cabbage and potatoes (happy Saint Patrick’s Day!) can morph from weekend projects to weeknight suppers.
So how does a pressure cooker work its magic? To begin at the beginning, so to speak, there are two unavoidable steps in all cooking. As chemistry professor Robert Wolke explains in What Einstein Told His Cook, “one is heat transmission—getting the heat into the interior of the food. That can be the bottleneck in many a ‘quick’ recipe, because most foods are poor conductors of heat. The other slow step is the cooking reactions themselves. The chemical reactions that change our foods from raw to cooked can be quite slow.”
“Microwave ovens circumvent the slowness of heat conduction by generating the heat right inside the food itself,” Wolke continues. “But many dishes such as soups and stews benefit from the slow marrying of flavors that takes place in water-based cooking methods such as braising: the searing and simmering of meats and vegetables in a small amount of liquid in a covered vessel.”
To make braising, for instance, go faster, you need to increase the temperature because all chemical reactions, including those in the kitchen, speed up at higher temperatures. “But there is a big obstacle,” Wolke notes. “Water has a built-in temperature limit of 212º F, its boiling point at sea level.” And why is that? Every square inch of the atmosphere—the blanket of air that covers Earth—weighs about 15 pounds at sea level, and water molecules must gain energy equivalent to a 212º F temperature before they can push through that 15-pounds-per-square-inch blanket and boil—that is, escape into the air as vapor. “Turn up the heat to flame-thrower intensities and the water or sauce will certainly boil faster,” clarifies Wolke, “but it won’t get one bit hotter.”
To overcome the greater blanket of pressure in a heated, sealed pressure cooker, however, the water molecules must achieve a higher energy, one equivalent to 250º F—and that becomes the new default boiling temperature. The superheated steam means quicker cooking; it will tenderize a tough, economical cut of meat in record time. Braised Asian-style short ribs, for example, which may take a good three hours or more, can be on the table in under 60 minutes. Since the pot is so tightly sealed, you need much less liquid than usual, and you’ll also use less energy: Not only are cooking times short, but once pressure is reached, the heat should be turned down as low as possible. On a personal note, I first learned how to cook with a pressure cooker on a sailboat, and there, a pot with a locked-on lid is worth its weight in gold.
A number of pressure cookers are available at different price points. In a January 2013 review, Cook’s Illustrated gave top ranking to the Fissler Vitaquick 8½-quart pressure cooker ($279.95) and the Fagor Duo 8-quart stainless steel pressure cooker ($109.95). I have the Fagor, and writing this column has made me hungry for Lorna Sass’ black bean soup with avocado salsa. Dinner is going to be a cinch.
Buying Tips From the Queen of Pressure Cooking
Sass’ books about pressure cooking are packed with a wealth of information (including timing charts and troubleshooting advice) and delicious recipes. Among her other books, by the way, is the instant classic Recipes From an Ecological Kitchen: Healthy Meals for You and the Planet (published in 1992, it’s out of print but available from online sources), as well as Short-Cut Vegan (first published in 1997 under the title Short-Cut Vegetarian, because at the time no one knew what “vegan” meant) and Whole Grains for Busy People (2009).
Check Out the Lid
Unlike a book, you should judge a pressure cooker by its cover. “First make sure that it’s simple to lock the lid into place and remove it after cooking. Then determine what kind of pressure regulator the cooker uses and how easy it is to know when high pressure is reached.” Second-generation cookers use a sophisticated spring-valve pressure regulator, which “have a small brightly colored rod or cylinder that pops up as the pressure builds. When the rod comes up high enough to reveal a designated mark, the cook knows at a glance when high pressure is reached.”
Check Out the Bottom
Beware of lightweight cookers. Look for one that’s well constructed and heavy, so it distributes heat evenly and prevents sticking and scorching. “Opt for an 18/10 stainless-steel cooker that has a three-ply bottom with an aluminum or copper sandwich.”
There should be at least three backup safety mechanisms for releasing excess pressure in case, for example, you forget to turn down the heat once high pressure is reached.
You want a cooker that operates at 14 to 16 pounds per square inch when it reaches high pressure. “Cookers that reach high pressure at 12 or 13 pounds PSI don’t get the job done as quickly.”
Select a cooker that requires 1 cup of liquid or less to reach high pressure. “A cooker that demands more liquid may result in excess gravy or a watery sauce.”
You can’t fill a cooker more than two-thirds full, so it’s a good idea to buy the biggest you can afford or have room to store. Even if you are cooking for just two people, Sass recommends an 8-quart (7-liter) cooker and certainly nothing smaller than a 6-quart (5-liter) model. “Some companies sell sets: an 8-quart and a 4-quart pot with a shared lid. It’s handy to have a second small cooker for preparing vegetables or risottos, but your primary cooker should be large.”