Another is that slow cookers are only good for what Finlayson calls "dump-and-stir" food — combinations of canned goods, soups and other things to create meals low in fresh ingredients and taste but high in sodium and other additives.
But slow cookers excel, she says, as "very effective time managers. They allow you to do the work you need to do anyway but at times that work best for your schedule. And they save you the time of attention while things are cooking."
Finlayson wrote her first cookbook, "150 Best Slow Cooker Recipes," in 2001, when her husband, Robert Dees, president of the cookbook publishing firm Robert Rose Inc., was rejected by seven cookbook authors he approached about doing a project on slow cookers.
So he turned to his wife, a journalist with a passion for food, some experience in recipe development and a lot of experience cooking fine food in her slow cooker at home. The book, revised in 2011, has sold about half a million copies.
When she was working on that book, she says, food writers were "aghast" that her recommendations included browning meat and softening vegetables before putting them into the slow cooker. It didn't fit with the cooker's dump-and-stir reputation.
"Now everybody does that."
The advantages of slow cookers haven't changed. Many of the ingredients can be prepared ahead and stored in the refrigerator until assembly with other ingredients in crock. They are safe to leave unattended all day and supper is ready when you get home.
It is important to control the liquid in slow cooking, Finlayson says. Because it does not reduce but forms as steam on the lid and drops back in, you can start with a little less liquid. Another trick she uses is to fold a tea towel over the top of the cooker, under the lid. This will absorb a lot of the liquid.
Finlayson says dried thyme and oregano and whole-leaf, stemmed herbs such as fresh thyme and rosemary can be added at the beginning and release their flavours slowly. Finely chopped fresh herbs should not be added until the last 30 minutes because their flavour will disappear over six or eight hours of cooking.
She doesn't add salt until the end because she doesn't want it to draw the juices out of the meat, or ingredients such as peas, corn or greens. Peppers also get bitter if cooked a long time.
The marketplace is exploding with slow cookers of varying sizes and shapes, with hinged lids, temperature probes and one kind that sits on a griddle that produces the heat.
Finlayson has three slow cookers — small, medium and large — for various uses. She prefers those with a removable crock for ease of cleaning and a timer to send the machine into "warm" mode after a specified time.
She also likes traditional slow cookers in which the heating elements are in the walls of the casing, rather than on the bottom, reducing the risk of scorching.
The usual warning signs of chipping, cracking or frayed cords all indicate a slow cooker should be replaced, she says. But the user should also ensure the pot heats up and cooks quickly enough to keep the food out of the "danger zone" in which bacteria can grow. For this reason, she says, it's worth investing in a good-quality machine.
One of Bruce Hunter's three slow cookers is 40 years old, but the ways he uses them has changed greatly.
"For years it was just for stews or chili," says the home cook from Watford in southwestern Ontario. Now he uses it to finish soups, for baked beans, macaroni and cheese, lasagna and even desserts.
But he uses it most often to cook a beef roast. He usually uses a cheaper cut marinated for several hours in Worcestershire and soy sauces. He applies non-stick cooking spray to the crock and scrunches foil into a circle to put in the bottom to keep the meat out of the liquid. After putting in the meat, he pours about 175 ml (3/4 cup) of beef bouillon over it and seasons to taste with salt and pepper and a little more Worcestershire or maybe garlic powder, onion rings or even barbecue sauce.
He turns it on high until the liquid is bubbling, then reduces the heat to low. He periodically checks the liquid level to keep it below the bottom of the meat and tests doneness with a meat thermometer. The result is tender, flavourful and moist meat.
Hunter and his partner also use the slow cookers when they entertain to keep turkey stuffing, gravy and vegetables such as squash, turnip and potatoes warm until the rest of the dinner is ready.
"They keep the food fresh, free up the stove and allow us to get some cleanup done before dinner."