Can This Easy Coffee Grounds Hack Really Fight Smelly Bathroom Odors?

Many people like to recycle spent coffee grounds, giving them a new life as everything from a fertilizer to a tool for fighting odors. But how effective are used coffee grounds as an odor absorber? While there isn't direct scientific evidence that proves old coffee grounds can reduce gross smells in your bathroom, they are widely used as a deodorizer in the home. According to a study in the Journal of Oleo Science, coffee grounds heated in a microwave and used as a carbonaceous material were able to control ammonia-based gases and minimize unpleasant smells in the air.

Coffee grounds are hygroscopic. That's a fancy way to say they absorb moisture, smells, and tastes, which is why coffee companies tell their customers to store coffee grounds far away from onions, garlic, and similar smells to prevent them from spoiling. On the other hand, those odor-absorbing properties are why many people use coffee grounds to fight bad smells in the refrigerator. Not only is this a great way to repurpose spent coffee grounds, but it's affordable as well as super easy.

So even though the science is inconclusive, coffee grounds may be able to effectively reduce bad odors in the bathroom and it could be worth a try. If you want to use this hack as a potential bathroom deodorizer, however, you'll need to make sure the coffee grounds are prepared correctly first.

If you want to use coffee grounds to absorb odors in your bathroom, they must be dried first. Otherwise, they could grow mold. Collect your coffee grounds and spread them out on a baking sheet covered in about six layers of newspaper (remove any possible metal staples). Make sure the layer is thin and evenly spread out and intersperse with additional newspaper strips to absorb excess moisture. Place the tray in the sun (make sure there's not any rain in the forecast) where there is good airflow. 

Shake your tray regularly to expose the bottom grounds to the sun and air until dry to the touch. The coffee grounds should be lighter in color when they're done. The drying time should take a couple of days, but this will depend on the weather. You can also try a dehydrator or traditional oven to dry the grounds even faster, or even use a convection oven as a food dehydrator. Regardless, it will take a few hours at low heat before the moisture is completely gone. 

Once dry, place the coffee grounds in an open container (or two) near the toilet, towels, or laundry basket to absorb damp odors. You can also use sachets, or fill up small fabric or paper bags and place these around the bathroom. Avoid placing these on top of fabrics that can stain. Replace containers and sachets regularly to avoid moisture build-up and prevent mold from growing on your coffee grounds. While there are many other life-changing coffee hacks out there, repurposing used coffee grounds to improve the aroma of a smelly bathroom is still a great option.