By David Joachim and Andrew Schloss
from Fine Cooking #115, pp. 28-29
"Set it and forget it." "It cooks all day while the cook's away." Marketing slogans like these promise foolproof cooking in a slow cooker. But the truth is, no technique benefits from complete neglect-if you just throw everything in the crock, turn it on, and walk away, you're likely to get soggy, bland results. Just a little bit of effort pays off with much more delicious food; the trick is in understanding the inner workings of your slow cooker, and knowing how to maximize its strengths while minimizing its weaknesses.
How do slow cookers work?
A slow cooker is composed of a covered ceramic crock set into a double-walled outer pot. Electric coils in the walls of the outer pot gradually transfer heat to the inner crock, which retains the heat extremely well, maintaining a consistent low temperature with minimal energy use (200 to 300 watts of electricity per hour).
Slow cookers are essentially closed systems. The heavy lid creates a tight seal, trapping heat and moisture and allowing for little to no evaporation. This is why slow-cooker recipes call for barely any liquid-about 2 tablespoons per serving for a sauce, 1/4 cup for stews, and 1/2 cup for soups (including the liquid from ingredients like canned tomatoes). During cooking, steam condenses on the inside of the lid and drips back onto the food, keeping it moist, so it can cook untended for most of the day without scorching or drying out. There's no need to stir because the ceramic crock distributes the heat gradually and evenly.
|Slow-Cooker Steak and Guinness Pie||Slow-Cooked Pot Roast with Mustard & Horseradish Gravy||Slow-Cooker Osso Buco|
What are the best kinds of foods to cook in a slow cooker?
Go for tough meats and dense, fibrous vegetables. The relatively low heat of a slow cooker (200°F to 300°F) allows the enzymes in meat to remain active for longer. Combined with time and moisture, these enzymes help turn collagen (connective tissue) into soft, rich-tasting gelatin, so beef chuck, brisket, short ribs, shanks, pork butt, and lamb shanks become fall-apart tender after long, slow cooking.
Hard root vegetables like beets, carrots, and sweet potatoes have tough fibers filled with hemicellulose and pectin. When slow cooked, these substances break down into smooth, gelatinous compounds and simple sugars. You can use soft and very moist vegetables like spinach and zucchini in a slow cooker, but they should be added in the last few minutes so they don't overcook.
One of the most surprising strengths of slow cookers is their ability to bake moist cakes like fruitcake and cheesecake even more effectively than an oven does. As in an oven, heat radiates from the walls of a slow cooker, but an oven doesn't retain moisture and a slow cooker does. Oven heat can brown the exterior of a moist cake and overcook or crack the surface, but with its superior moisture retention, a slow cooker eliminates this problem. Just lay a folded kitchen towel under the lid to keep condensation from dripping onto the cake.
What are the challenges of a using a slow cooker?
The biggest challenge is that slow cookers don't sear or brown food, which is one of the main ways to make food-especially meat-delicious. While it might seem convenient to dump everything in a slow cooker and walk away, you'll get far better results by browning meats and vegetables in a skillet before adding them to a slow cooker. If you don't want to have to wash an extra vessel, you can buy a "brown and braise" slow cooker, which has a crock that can be used for searing on the stovetop, too.
Browning ingredients before they go into the cooker also has a food-safety benefit. Most harmful bacteria grow in the "danger zone" between 40°F (refrigerator temperature) and 140°F (very hot tap water temperature). Browning begins at around 250°F and kills most surface bacteria; the slow cooker's extended cooking time takes care of the rest.
To keep harmful bacteria from growing in a slow cooker, never put frozen foods directly into the cooker; defrost and brown them first. Nor should you reheat refrigerated leftovers in a slow cooker. Not only will the food stay in the "danger zone" for too long, but since it's already been cooked once and its cell structure has broken down, bacteria can spread throughout the food more easily, especially in the slow cooker's warm, moist environment.
This takes care of the hows and whys of slow cooking. Read our Slow Cooker Dos and Don'ts for even more tips and tricks.