Food & dining

The wonder of cooking in a bag

Put a just-boiled pot of stew or potatoes in the Wonderbag, and hours later you have dinner.
Put a just-boiled pot of stew or potatoes in the Wonderbag, and hours later you have dinner.

When Sarah Collins, a South African entrepreneur with a passion for the environment and for empowering women, came up with the idea for an electricity-free portable slow cooker, a friend sewed the first prototype for what became the Wonderbag.

Last year, Fortune magazine named Collins one of the most powerful women entrepreneurs, handing out free Wonderbags in Africa and establishing factories in poor South African communities. “Our goal is to create over 8,000 jobs by September 2016,” writes Collins in an e-mail. For every bag sold in the United States and United Kingdom, a free bag is donated to a needy African family. In this country, bags cost $50. In South Africa, the average price is $15, and bags are largely sold by African women trained by her company; bags sold online are going to 16 countries.

The Wonderbag is 15 inches in diameter and 7 inches tall, and looks like a cotton bean bag you might sit on. It behaves like a cooking vessel that ancient people might have used. You place ingredients for a slow-simmered recipe in a cooking pot (up to 9 quarts) with short handles. Bring the food to a boil with the lid on, and let it boil for a few minutes. Take the pot off the burner and place it in the bag. Pull the drawstring tight and let it sit for several hours.


The bag is filled with repurposed foam remnant chips from furniture factories. “This material would otherwise end up in a landfill,” writes Collins.

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Because food sits in the Wonderbag for so many hours, the bag has been tested in South African labs. “The FDA recommends that one not eat cooked foods if they have been sitting between 135 degrees Fahrenheit and 70 degrees Fahrenheit for longer than two hours,” writes Collins. “Most recipes stay well above 135 degrees Fahrenheit for at least 4 or 5 hours and some up to 12 hours.” She recommends checking the temperature with a thermometer when you open your Wonderbag. Since the food is in a lidded pot, it never comes in contact with the bag itself or the foam pieces.

The way it works is that the bag uses heat retention to cook, says Collins. The bag slows the cooking process, she says, “by insulating the heat, allowing for more cook time.” She adds: “There are many factors that play into how hot the pot stays and for how long; cast iron and metal work best, the fuller the pot the better for heat retention.”

Wood-fire cooking is the source of major social, economic, and environmental issues in Africa, says the entrepreneur. “A typical woman woman will cook food in a pot over an open fire, and will have to monitor the pot for hours. Smoke is being inhaled by the women and children who tend the fires.” She says that the bag saves about 30 percent of a family’s income when they make the change. “They save water, the risk of disease and death from smoke inhalation is reduced,” she says. “Deforestation is minimized, and time is freed up to allow children to go back to school and women to seek employment.”

When I first heard about the Wonderbag I thought of my mother on Sundays in soccer season in Denmark. She would peel potatoes (when I was young, no self-respecting Dane would consider a hot meal without potatoes and gravy), bring the lidded pot to a boil, cook it for two minutes, then wrap it in several layers of newspaper before burying it at the foot of her bed under her heavy goose-feather duvet. She would accompany my father to a soccer game to watch him referee and when they returned home, the potatoes were done.


My mother didn’t invent an early Wonderbag. Danish women, and women around the world, had already done that. She was raised on a farm and my grandmother would use a hay box for the same purpose. For hundreds of years, cooks placed hot food in the ground.

To test the accuracy of my childhood memory, I took six large red potatoes, left the skins intact, quartered them, and just barely covered them with cold water. I brought the water to a boil, cooked the potatoes for two minutes, then wrapped the pot in newspaper. I could not replicate the duvet with goose feathers so instead put the pot inside two comforters to sit for four hours. When I opened the pot, the water was still hot and the potatoes cooked through; the texture was perfect.

It is unlikely the Wonderbag will be used often for cooking potatoes. It seems more suited to long-simmered stewy dishes. But I was eager to compare it with my makeshift cooker.

I prepped another six potatoes, and proceeded the same way. I put a small silicone trivet in the bottom of the Wonderbag and placed the pot on top (per the instructions). Four hours later I had wonderful boiled potatoes. The handles on the pot were so hot that I needed potholders; an instant-read thermometer recorded the water temperature as 161 degrees.

The easy and uncomplicated Wonderbag has one small drawback: Because of the bulky filling material, it does not collapse, so takes up space when not in use.


In my own kitchen, where waste-not want-not is the common practice, there will be a big pot of soup in my future — made with potato water — and left again for the afternoon in a double layer of comforters.


Ingrid Lysgaard can be reached at