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Can machines designed for the same simple purpose—cooking food slowly enough that you can walk away—be all that different? You'd be surprised.
A slow cooker promises to be a little fantasy grandmother who sits in the kitchen all day cooking for you, but use the wrong cooker and that dream could fizzle. A cooker might run hotter than expected, drying out the food or turning it mushy, or slower than you want, so dinner isn’t ready when you are. Then there can be issues with hot spots, which make food cook unevenly. And what if operating your machine is so confusing that you have to pore over the manual each time you use it?
For the ideal machine that would deliver a properly cooked meal and be absolutely simple and intuitive to use, we went shopping. Previous experience taught us that glass lids were a must, as they allow you to see progress without losing heat. So were oval-shaped crocks, as these can accommodate large roasts and offer more versatility than round crocks. We also wanted a generous 6- to 7-quart capacity. With these criteria in mind, we rounded up eight models priced from $39.99 to $148.71.
Slow cookers rely on covered moist-heat cooking, so of course we wanted to evaluate how well each model performed the classic task of turning a tough cut of meat tender. But since people use their slow cookers for much more than just braises and stews these days, we’d throw a few other recipe challenges at them, too. We chose recipes with a range of cooking times, using both low and high temperature settings. (Most recipes give you the option to cook for a shorter span on high or about twice as long on low. Generally the choice is about convenience, though delicate foods often require the low setting.)
We started by asking testers to evaluate how easy the slow cookers were to fill, set, turn off, and empty. Only the cheapest model in our lineup had a manual control (a simple dial, with no timer or automatic switch-off). We much preferred digital programmable cookers, which automatically switched to “warm” when the cooking time was up.
But setting the programmable cookers wasn’t always easy. We wanted intuitive controls, but several models had so many buttons with such confusing layouts that our testers couldn’t tell if they’d set them correctly. Then there was the “smart” slow cooker that ran via a phone app with such a pared-down control panel that it left most testers puzzled and frustrated. Yet another cooker’s controls let you set only even-numbered cooking times (2, 4, 6, 8, or 10 hours) and indicated cooking progress with a cryptic series of lights. But one model in particular was a pleasure to use: Its controls were unambiguous, each button clicked satisfyingly and lit up when pressed, and within a few seconds the clock began counting down so you knew that it was running.
Handling the slow cookers presented new challenges. Some handles became red-hot during cooking or were set too close to the hot rim of the housing. While we liked that the three products in our lineup that had metal inserts were featherlight and that we didn’t have to worry about cracking them, two of them became too hot to touch. Surprisingly, the heaviest crock in the lineup, a ceramic model, was also the easiest to use. It had protruding handles that were easy to grip and stayed cool. We found that this cooker was the only model that held close to the advertised capacity of 6 to 7 quarts and was also the only one with clear minimum and maximum fill lines.
It was time to start cooking. First up: braising chuck roast into pot roast. Two models produced mixed results, slightly overcooking some pieces and leaving others a bit underdone and chewy. A third model never rendered the meat fully fork-tender, even after extended cooking.
Next we made delicate boneless, skinless chicken breasts. Our recipe calls for laying four breasts in a row across the bottom of the crock. In three models (two of which were guilty of unevenly cooking the chuck roast), the breasts nearest the shorter, curved ends of the cookers cooked too fast. They climbed as high as 185 degrees, becoming dry and rubbery, before the pair in the center reached the target doneness temperature of 160 degrees. While cooking speed varied, all fell within the range indicated in our recipe.
Next up: turkey breast. In previous testings, we found that some slow cookers had a hot spot along the back wall of the cooker, which risked overcooking larger cuts that pressed up against it. This time around we were pleased to find that this hot spot wasn’t an issue, although one cooker that unevenly cooked chicken breasts overcooked the turkey where it touched the narrow ends of the crock. Again, cooking times varied, but all models finished within our time range of 5 to 6 hours on low.
Aside from the unevenly cooked chicken and turkey, all of the food was passable. But our front-runner produced evenly cooked food every time.
Why did some cookers run fast and others slow? Why could some cook food evenly and others not? To find out, we dismantled a duplicate set of cookers with the help of Gregory Thiel, a postdoctoral associate in mechanical engineering at the Massachusetts Institute of Technology. Here’s what we found: Most of our models are “traditional” slow cookers, where food goes into a ceramic stoneware crock that absorbs and transmits heat slowly. These models had heating element strips made of nickel and chrome (“nichrome”) wire that wrapped around a fiberglass strip that belted the crock. When the cooker is on, this wire heats up more or less powerfully depending on the wattage and the setting. This construction tends to create hot spots near the element—particularly at the curved ends of the cookers, where the element surrounds the food more closely.
But two models with this belt-style construction actually did manage to cook food evenly, even at the ends. Opening up their housing revealed thick, heat-resistant padding and foil heat shields packed inside (the other models had been empty except for the heating element). The insulation buffered the pot from contact with the heating elements, preventing hot spots; it also explained why these two models—one of them our front-runner, from KitchenAid—tended to run a bit slower.
Two other models were designed very differently, with lightweight, nonstick-coated aluminum pots that sat directly on a hot plate with stove-style electric coils embedded inside that also heat more or less powerfully depending on the setting. This design encourages even cooking from end to end, though the thin metal pots of these slow cookers (by Cuisinart and Ninja) cooked hotter and faster than ceramic-crock models.
The remaining cooker was a hybrid style made by Crock-Pot, with a metal crock and a traditional belt-style heater. Like the other two models with metal pots, it cooked a little fast. The KitchenAid model we liked so much has a useful feature: a sensor that automatically monitors and adjusts the cooking temperature so that it levels off and stays below boiling (ideally, food should stay at a simmer), helping further guard against overcooking food. Without such a sensor, the temperature of the crock pot’s contents will just keep climbing until it boils, whether set to low or high, simply because the heat is on (when set to low, it just takes longer to get there).
This was made clear in our next test: We tracked the temperature as each model heated 4 quarts of water over a period of 6 hours on high and then 12 hours on low.
The KitchenAid 6-Quart Slow Cooker With Solid Glass Lid ($99.99), our former winner, handled every recipe with perfect results, albeit a bit slowly. Its thick stoneware crock, insulated housing, built-in thermal sensor, and crystal-clear controls put a well-thought-out design at your service—and at a moderate price. The Cuisinart 6-Quart 3-in-1 Cook Central ($148.71) is also a solid choice. It offers the advantages of a light, unbreakable metal crock with stay-cool plastic handles, as well as a brown-and-sear function that lets you skip using a separate skillet before slow-cooking in recipes that call for it.
We tested eight 6- to 7-quart slow cookers, preparing a variety of recipes using both low and high temperature settings and varied cooking times. We used temperature probes to map heating patterns, and a panel of testers evaluated how easy the cookers were to use and clean. We also dismantled a set of the cookers to understand the placement and type of heating elements they contained. All slow cookers were purchased online and appear in order of preference.
We prepared boneless, skinless chicken breasts; whole bone-in turkey breast; and pot roast. We evaluated the texture and flavor of the food and rated the cookers on the uniformity of cooking. We did a final round to test the built-in browning function, when available. We gave highest marks to cookers that produced evenly cooked, juicy, and tender foods every time.
Ease of Use
We evaluated how easy the cookers were to fill, set, and maneuver, including the intuitiveness of controls, displays to monitor cooking, weight of the crock, size and shape of handles, and whether the handles became hot.
We washed each model six times by hand and 10 times in the dishwasher (unless the manual instructed not to do so). We gave high marks to models that were easy to clean, with few nooks and crannies to trap food or water. We also gave preference to pots and lids that were dishwasher-safe and emerged from 10 dishwasher cycles good as new.
To map heating patterns, we used temperature probes to track the temperature of each cooker’s contents as it heated 4 quarts of room-temperature water over a period of 6 hours on high and 12 hours on low.
Our former champion won again for its well-designed, straightforward control panel with a countdown timer that was simple and unambiguous to set and allowed us to monitor progress at a glance. The roomy, heavy stoneware crock cooked gently and evenly and never boiled, so food emerged tender and juicy. We loved that its broad, protruding handles with grippy textured undersides usually stayed cool enough that we could pick up the crock without potholders. Thick insulation kept heat directed toward the crock, and a built-in internal temperature sensor gave this slow cooker extra “brains” to keep the temperature below boiling, which helped guarantee better results.
We loved the lightweight, nonstick metal crock and stay-cool plastic handles that made this model so easy to maneuver and clean. The pot cooks directly over a built-in hot plate, and the long, rectangular crock provides abundant surface area that’s in contact with that heat source, so this model tends to run a little hotter and finish faster than our winner but cooks evenly (built-in temperature control was evident when we monitored using a thermocouple). We suggest checking recipes early for doneness. Its brown/sauté function eliminates the need for a separate skillet, but it’s slower than a skillet and food steamed a little due to the crock’s high sides. Our testers disagreed on whether setting the cooker was easy or a little confusing. A solid performer, it’s a great choice if you hate to lift heavy crocks or worry about breakage.
Like the Cuisinart, this model has a thin, long, rectangular metal crock and cooks fast but evenly. It has both a built-in hot plate and a belt-like heating element for different cooking functions. While the cooker was easy to set, its controls are a little complicated because of its multiple functions (steam, roast, slow-cook, etc.). We disliked that its slick, bare metal handles get very hot, and while its brown/sauté function works, it’s noticeably slower at browning food than the Cuisinart, probably due to its lower wattage. (Note: We did not test the “steam-baking” or “steam-infused roasting” functions.)
The metal crock on this cooker gets very hot, so cooking runs slightly fast, though it cooked evenly. The crock can be used on the stovetop for browning and searing before placing it in the cooker to slow-cook. However, we had quibbles with the design: Its metal handles became quite hot; the slick ceramic coating still felt greasy after repeated hand washing, but the dishwasher is not recommended; and the thin lip of the crock meant that its lid sometimes slipped into the pot when jostled. Some testers found the controls confusing.
We loved the lid latch and rubber gasket that prevent spills if you take this pot to a party, and we loved the simple controls and low price. Its food was cooked acceptably, although its temperature climbed to boiling (or barely below) on both high and low settings. But this model lost major points because we couldn’t set odd-numbered cooking times as called for in many recipes. Our only choices were 2, 4, 6, 8, or 10 hours, and there was no countdown timer (instead, lights next to the numbers extinguish as the cooking time decreased, giving a rough approximation of progress).
This cooker is very slow. Its wattage is comparatively weak (250 watts), and its housing contains insulation, which is an advantage for helping prevent hot spots but made this slow cooker downright poky. Food was generally good, with the exception of pot roast—it didn’t become fully tender within the recipe time frame. The wifi-enabled functioning was more annoying than awesome. We had to fire up an app to do anything beyond simply turning on the cooker and selecting a temperature setting. With no countdown display, we couldn’t check progress at a glance. The app itself was jumpy and often left us guessing whether we’d inadvertently turned the pot off from afar. We’d strongly prefer to have full controls on the cooker and not just via the app.
This cooker was very simple: On high, it simply got hotter until it hit boiling; on low, it climbed steadily. While its food was not inedible, it emerged unevenly cooked in each of our cooking tests: The outermost chicken breasts were overdone before the center ones were ready, and the pot roast was a little dry in spots and not yet tender in others. Small handles on the heavy stoneware crock were set too close to the hot collar of the metal casing.
Large and inexpensive with a big, heavy pot, this uninsulated manual cooker cooked unevenly, which was especially noticeable with chicken breasts but also with pot roast and turkey. While it’s easy to set, it’s not that convenient to use: It has no countdown display, so you can’t monitor progress unless you set a separate timer, and it can’t automatically switch to warming mode after cooking is done—you have to return to turn it down or switch it off.