Scientists Find a Way to Convert Stale Bread Into Fresh Drinking Water and It's Mind-Blowing
Published April 11 2025, 11:46 a.m. ET
A person dusting off the flour from a bread
In most American households, bread is the ingredient that is pampered and often idolized for the delicious crispness it offers so generously. But oftentimes some unattended slices sitting in the fridge start to become tender, soggy, and maybe moldy. It's heartbreaking to bid them farewell and toss them in the kitchen bin. Seen another way, it's unfair for these stale slices to have been ditched so brutally despite their timeless offering of taste. But not anymore. In February 2025, a team of researchers published a report in Royal Society Open Science, saying that even stale bread can prove to be valuable, specifically for splitting salt out of water and making it drinkable.
Cut-out slices of brown bread
“Waste bread is reported to be discarded at a high rate and can serve as an abundant and cheap reactant,” wrote the researchers from Saint Vincent College, the University of Pittsburgh, and the University of Pennsylvania. Doctor Adam Wood, one of the researchers in the team, previously published a paper in the journal RSC Advances, describing how bread can be turned into carbon electrodes. The high carbon content of the bread can be utilized to convert the bread into these electrodes, which act as electrical conductors that can desalinate water. In this experiment, the team used Pepperidge Farm whole-wheat bread for the purpose.
Slice of a whole grain bread
The team experimented with two methods to transform bread into carbon electrodes. The first method involved stamping and pressing the bread into a 3D-printed mold to convert it into a desired shape. In this case, they used a zigzag mold. Once the bread was shaped into the design of the mold, they heated it for an hour at an extremely high temperature of 800°C or 1472°F. The Institute of Food Sciences & Technology explains that when bread is heated at such a high temperature, the carbon trapped in the layers of its dough gets liberated into the form of carbon dioxide. As the scorching furnace blasts the bread with heat and spews vortices of nitrogen, the bread eventually turns into a solid carbon electrode.
Scientist performing an experiment with test tubes in a laboratory
The second strategy researchers used to repurpose stale bread was blending the bread with water. Once the bread turned soggy and mushy, they chugged it in a blender and molded it in the shape they required for the electrode. The gooey bread clump was then popped inside an oxygen-free oven, which charred the bread at 800°C in a heating process known as pyrolysis. Pyrolysis, according to HowStuffWorks, is “the process of heating up a substance to incredible temperatures — more than 500 degrees Celsius (932 degrees F).” In an oxygen-free environment, the bread doesn’t catch fire. Instead, it is carbonized, which is exactly what happened in this case.
Person cuts a bread loaf into slices
After implementing both strategies, the researchers noted that while the first method helped offer precise shapes, the second one proved to develop sturdier electrodes. But the remarkable part of this experiment was that both methods were absolutely chemical and dope free. Plus, the methods offer a bright vision of what scientists could develop with bread in the future. According to Tech Xplore, the team plans to continue working on this research with the hope of refining the process and developing a way to “mass produce ‘green’ electrodes.”
A woman is drinking a glass of water.
The ultimate objective is not merely to reduce the bread waste but rather to develop a low-cost “capacitive desalination system” that could be used to bring fresh drinking water for the people worldwide. As for the stale bread lounging in your fridge, well, you can still use it to make things like bread pudding, panzanella, toasts, croutons, ribollita, breadcrumbs for soups, French toast casserole, Fattoush, and more, as people shared in a Reddit thread.