Original article written by Nicolás Rivero.
The Case for Bar Soap
Choosing the most sustainable method for washing your hands or showering often means opting for a traditional bar of soap made from plant oil or animal fat combined with lye. According to a study from ETH Zurich’s Institute of Environmental Engineering, bar soap reduces greenhouse emissions by about a third compared to liquid soap.
Skin Benefits and Market Trends
Tony O’Lenick, president of the Society of Cosmetic Chemists, explains that while bar soap is a natural and sustainable product, it can dry out the skin. This has led many people to prefer liquid hand soaps and body washes, which include moisturizing ingredients and have captured about half of the American soap market since their debut in the 1970s and 1980s.
Joan Li, a senior beauty and personal care analyst at Mintel, notes that the additional benefits of liquid soap have made it more popular, while bar soaps are now also incorporating artificial and petroleum-based ingredients to avoid being too drying. Meanwhile, some liquid soaps are adopting simpler, natural ingredients to appear more eco-friendly.
Ingredients Matter
To choose the greenest soap, consider the ingredients and packaging. Traditional soap is made by combining fat and lye, creating surfactants that clean by helping water wash away grime. In contrast, many modern soaps are actually detergents, derived from petroleum, which are more energy-intensive to produce and generate significantly more greenhouse emissions.
Reading labels is crucial, as many soaps, including bars, contain detergents with ingredients like sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES). True soaps, however, use animal fat or plant oil and lye, often with added glycerin, scents, and essential oils.
Packaging and Environmental Impact
When it comes to packaging, bar soap generally has the upper hand. It usually comes in minimal, recyclable packaging, while liquid soap is often in plastic containers with pumps that are difficult to recycle. The Swiss study reveals that packaging liquid soap is 19 times more energy-intensive than bar soap and transporting it creates nearly eight times the carbon emissions.
Water Usage and Scrub Time
Additionally, the way we use soap impacts sustainability. Liquid soap users typically spend less time lathering, thus using less warm water, while bar soap users consume about 40 percent more water. Despite this, bar soap remains the more eco-friendly option overall.
Conclusion
Ultimately, the type of soap you use isn’t a major factor in your carbon footprint; the study notes that washing hands generates carbon emissions equivalent to charging a phone once or driving a car 200 feet. However, considering billions of people wash daily, collectively switching to more sustainable products could make a significant difference. Balancing sustainability with comfort is key, as O’Lenick points out: if the soap doesn’t feel good, it won’t be popular, regardless of its eco-friendliness.