Insulated Shopping Totes

Unlike regular reusable shopping totes, insulated shopping totes are designed to keep refrigerated and frozen foods cold on the commute home from the supermarket. We purchased six, priced from just under $10 to almost $40, including puffy models boasting patented insulation and an innovative model with freezable gel packs sewn into its lining. We were looking for a comfortable, easy-to-carry tote that could keep our groceries at a food-safe temperature for at least an hour. To evaluate comfort and design, we loaded each with an identical assortment of bulky, heavy, and fragile groceries (12 items total) and took each bag for a 10-minute walk. We tested their construction and strength by weighing down the bags with 25 pounds of nonperishable groceries and suspending them from their handles for 24 hours. We also monitored how long half-gallons of orange juice remained at a food-safe temperature in 70- and 90-degree rooms, putting an identical arrangement of groceries in a plain paper grocery bag for comparison. Our final test: stain and odor resistance. We smeared the interior of each tote with a measured amount of milk, yellow mustard, and tuna packed in olive oil, waited 48 hours, and then attempted to wash them clean. 

We expected bags with thick walls and layers of insulation to fare best, since these sheets of fabric and foam act as barriers, keeping the cold air in and the warm air out. So we were puzzled when a large tote with the thickest foam insulation and the puffiest walls (0.40 inches) kept juice cool for just 40 minutes in a hot room, not much better than the paper bag. Another tote with soft sides that didn’t shut all the way performed inconsistently; depending on the mix of items and arrangement in the bag, it kept the contents cold—or not. We realized that the size and design of the bag were as important as the amount of insulation. The best bags sealed tight and were of moderate size, between 12 and 20 inches at their widest and no taller than 16 inches—dimensions that could accommodate a gallon of milk and a dozen other items. The reason is simple: Insulated bags work best when they’re full because there is less room for warm air to circulate around the groceries. That large tote with thick walls would need a cart’s worth of groceries to be effective. Two conventionally insulated totes succeeded at keeping orange juice at a food-safe 40 degrees for 1½ to 2 hours in both tests. As for that innovative model with freezable gel packs embedded in the lining, it lasted a whopping 4 hours in a 70-degree room and just longer than 3 hours at 90 degrees. And even when we used it without freezing the bag f... read more