Reusable Kitchenwares Aren't Always Best, Surprising Study Reveals

"Swap disposables for reusables" is one of the first pieces of advice you will hear when it comes to making your kitchen a greener, more sustainable place. Plastic sandwich bags, single-use straws, throwaway cutlery, and disposable beverage cups have become vilified in recent years because they're mostly non-recyclable, non-biodegradable, and have such short lifespans.

However, researchers from the University of Michigan suggest we've jumped to conclusions too quickly when it comes to assuming all reusables are better than disposables. They set out to measure the environmental "payback period" for four categories of kitchen items—drinking straws, sandwich bags and wraps, coffee cups, and forks—and determined how many times a product must be reused before its environmental impact per use equals that of a comparable single-use plastic product.

The resulting study, published in the "International Journal of Life Cycle Assessment," reveals some surprising discoveries. Three common reusable items—beeswax wraps, silicone bags, and bamboo reusable straws—ranked worse than their disposable plastic counterparts. A press release explains, "[They] never reached the break-even point in any of the three environmental impact categories assessed in the study: energy use, global warming potential, and water consumption."

The reason lies in the tap water and manual energy required to wash these items, making them more resource-intensive than items that can go in a dishwasher. "For example, beeswax sandwich wrap, which must be manually washed and has a large surface area, was never able to reach the break-even point when compared to disposable plastic sandwich bags."

Fortunately, nine of the 12 items analyzed did reach that break-even point, even with regular washing after every use. The press release says that "all three reusable fork alternatives (bamboo, reusable plastic, and metal) had payback periods under 12 uses for all three environmental impact categories." 

Coffee cups were the only item with a single reusable alternative, and these had the shortest payback period of all. Their impact can be reduced even further when users do a quick cold-water rinse instead of a full hot-and-soapy wash.

As a dedicated user of beeswax wraps myself, I find these study results somewhat hard to swallow. I reached out to the authors for further comment on optimal washing practices, since I always wipe down my beeswax wraps with a cold damp cloth and usually no soap, which hardly seems like an environmental drain.

Hannah Fetner, one of the study authors, tells me:

"We modeled typical (not optimal) wash behavior for generic products. Your choice to wash with a wet rag and no soap would definitely use less resources and make it more likely to break even. I can't speak for the average person, but I know that when I had beeswax wraps I washed them in a basin of water with soap. This type of discussion brings up the fact that we often don't have very detailed data on consumer behavior because it's hard to quantify such a large variation."

Some takeaways include opting for items that can be washed in a dishwasher, rather than by hand; using items for as long as possible to extend their lifespan and thus carbon footprint; ditching certain items altogether, like straws, whenever possible. 

Fetner sums it up for Treehugger: "My recommendation for consumers is to use reusable products as many times as possible and to be mindful of washing habits. Following washing best practices could make some reusable products that did not break even in our study more favorable than single-use products."

It's important to remember that, in the big picture, these kitchen items don't add up to a significant portion of one's carbon footprint. The study authors remind readers that opting for greener modes of transportation, energy, and food have a bigger impact than focusing one's attention on kitchen tools.