Mason Jar Adapters

From Brooklyn to Boise, Mason jars are being reused as everything from drinking cups to travel food-storage containers. But the traditional lid offers limited functionality.

We tested one product that promised to turn a jar into a to-go container: a 6-ounce plastic tub that drops inside a widemouthed jar but stays aloft thanks to a wide, flat rim. It turned jars 1 pint or larger into two-part containers, perfect for housing snack duos like hummus and carrot sticks or yogurt and granola, and was leak-free (we checked by dropping desiccant into the bottom of the jar, filling the insert with water, and shaking vigorously). We could fit generous portions of most snacks, save for large, crunchy items like tortilla chips.

A second product is a screw-on, flip-top plastic drinking lid, sold in both regular and widemouthed sizes. We found it comfortable to drink from and virtually drip-proof, even when we shook it upside down and tossed it into a commuter’s backpack. As a salad dressing shaker, it poured neatly and the jar’s grooves didn’t become slick with oil like they do when twisting on and off the traditional Mason jar lid.

Both products are top-shelf dishwasher-safe and resisted staining, even when we left them filled with iced black coffee or room-temperature tomato sauce for 8 hours. Neither can be used for hot items, as the glass jars aren’t insulated and will burn your hand, but we transport enough chilled or room-temperature foods and drinks to make these worth the small investment.