Liquid Dish Detergent

Update: February 2012

Our previous winning liquid dish detergent, Method Go Naked Ultra Concentrated Dish Detergent, has been discontinued.

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Liquid dish detergent is one of those household staples that most of us don't put a lot of thought into. After all, how different can dish detergents be? They all work, right? Most of us buy what's on sale or whichever product smells or looks the best. In recent years, natural, more ecologically friendly, dye- and perfume-free detergents which swap out all or most of the petroleum-based cleaning agents for vegetable-based ones have hit the market. Curious about how they stacked up against traditional brands, we rounded up seven detergents (in each brand's original or most basic formulation), rolled up our sleeves, and headed into the test kitchen to put them through their paces.

To test each detergent, we systematically burned carefully measured portions of several classic hard-to-clean foods—beef and bean chili, béchamel sauce, and skin-on chicken thighs marinated in teriyaki sauce—onto stainless-steel skillets. We measured out equal ratios of each dish detergent and temperature-controlled water, submerged the dirty pans, and started scrubbing, counting our strokes for each pan. At the end of the testing, every pan was clean: Yes, all dish detergents work. But a few detergents stood out above the others for being able to clean the pans as much as 25 percent more quickly. We were very surprised to find that the two most effective dish detergents were the "natural" ones: our assumption had always been that the more expensive eco-friendly detergents didn't clean as well as the mass-market products.

To help us better understand our kitchen results, we turned to our science editor, who explained that the active ingredients in dish detergents are chemical compounds called surfactants. Surfactants help oil and water (which normally repel each other) mix; when made "wet" by the surfactants, the oil-based food grease is surrounded by water droplets and carried away, resulting in clean dishes. The amount and type of surfactants will determine how effective a dish detergent is at attacking grease.

Since our two “natural” samples primarily use vegetable-based surfactants and the other detergents in our lineup use considerably more petroleum-based surfactants, one could assume that vegetable-based cleaning agents are more effective. Not so fast. In fact, many of the mass-market brands contain surfactants of both origins and independent researchers have not found that vegetable-based surfactants are inherently more effective than petroleum-based ones. So why did these two outperform the other detergents?

It may come down to cost. Representatives from our winners say they spend the money to load their products with high concentrations of effective surfactants, which ensures a high-performing detergent. We'd have to say this approach works.