The Confusion

• Comparison of several similar recipes for beef shoulder/chuck pot roast and pork shoulder/butt, cooked with potatoes, carrots and onions, illustrates the breadth of "it depends." Recommendations for cooking roasts from 1 1/2 to over 4 pounds in weight are markedly similar: 4 to 6 hours on a high setting, 8 to 10 hours on low. Since oven-times are usually closely related to meat weight, slow-cooker guidelines seem very confusing.

Slow Cooking Safety

• The goal of slow cookers is to heat food to 165 Fahrenheit, the safe cooking temperature according to the United States Department of Agriculture. At 165 F, pathogenic organisms responsible for food poisoning are destroyed. Slow cookers, depending on the brand, may offer multiple settings from 140 F to 212 F and almost always offer high-heat and low-heat options. Most cookers simmer food without bringing it to a full boil. According to the Utah State University Extension, cookers are operating correctly if they reach 140 F within 3 hours and 180 F within 8 hours. Manufacturer West Bend advises that cookers always be set at 180 F or above unless they are just reheating food, which can be done at lower temperatures.

Cooking Proteins

• A good shoulder/chuck pot roast is moist and tender. Slow cooking contributes to both these cooking goals. Covered cooking over a long period retains moisture, both in the form of broth and juices from the meat and vegetables. Slow-cooker temperatures are adequate to facilitate the melting of connective-tissue collagen into gelatin, a tenderizing process that begins when meat reaches a temperature of 175 F. Warm, rather than hot, temperatures also enable relaxation of protein fibers, making meat softer in texture.

Food Quantity and Cooker Size

• The size of your cooker and the amount of food in it can affect cooking time. Cookers are designed to work best when half to two-thirds full, counting all ingredients and liquid. For best results, place a 2-pound roast in a 3- to 4- quart cooker and a 5-pound roast in a 5- to 7- quart cooker and bring liquid above the halfway mark. Liquid level is very important because of the capacity of liquid to conduct heat. Each roast can be expected to cook well at a high setting for 4 to 6 hours or at a low setting for 8 to 10 hours. Total ingredients and how they fit in the cooker have a stronger impact on cooking times than the size of any particular ingredient.

Your Cooker's Temperature Range

• Cooking times and oven-time equivalency charts are also hampered by the temperature ranges of different brands of cookers. Measuring the temperatures reached by your cooker will give you the clearest picture of where it fits on the general range of cooking times. The high setting on some cookers, for example, can reach as high as 300 F, rather than the more common 200 to 212 F level. A high-range cooker might need only 7 hours for results requiring 9 hours in a lower-range cooker. According to the Utah State University Extension, most raw meats or raw-meat-vegetable combinations need 8 hours at a low setting. Using a thermometer to test cooker-liquid temperatures lets you predict whether your cooker will exceed or lag behind the general guideline.

Solving the Confusion

• The apparent vagueness of slow-cooker timing, therefore, is a reasonable description of how the cooker and its contents work together. Use general directions as a guideline and keep notes on the results you get from your own cooker to take full advantage of this labor-saving cooking technique.