When most people think about coffee and laundry, they’re trying to figure out how to get the stain from their morning espresso out of their shirt. But, a popular hack suggests adding coffee to a load of dark laundry to keep colors from fading. But is there any truth to this caffeinated cleaning trick?

While there might be some benefits, putting a cup of coffee in with your clothes could actually end up doing more harm than good.

The idea is that pouring a cup of coffee into your dark laundry during the rinse cycle can keep the colors from fading. Coffee serves as a natural dye, so some believe it can support the black dye in your clothes to keep them looking newer for longer.

Unfortunately, it’s not a great hack. Coffee might have some dyeing effects when you’re washing dark clothes, but consider how diluted it will become in all of the water from your washing machine—especially if you have an older model. It’s likely not going to offer the darkening effect you’re looking for.

On the other hand, many of today’s high-efficiency washing machines use less water. So you’d have the opposite problem. The coffee could actually end up staining your clothes. That’s a tye-dye effect no one wants to deal with.

If you really want to preserve the color of your dark clothing, choose a high-quality detergent, add a fabric conditioner to each load, and wash your darks in cold water to prevent the colors from leaching out.

There are plenty of useful laundry hacks that can be used to keep your clothes looking great, but when it comes to coffee, it’s better to enjoy a cup, yourself, rather than try to dye your darks.