I Got Sudsy (and Science-y) to Find the 2 Best Dish Soaps for Clean Dishes Every Time

If you love to cook, you’ll eventually face the inevitable byproduct of your efforts: a pile of dirty dishes. As a recipe developer, I wash mountains of sticky bowls, greasy skillets, and crusty spatulas every day, and I have to admit, it’s my least favorite task. There’s no way around it, but I wondered: Is there a better way through it? 

Dish soap may not be the most glamorous darling of the kitchen. Still, there’s a lot of fascinating science packed into those unassuming bottles, and dish soap’s overall effectiveness can make washing dishes a chore—or a pleasure. For a product I use every single day, I had never given much thought to dish soap. But as I gathered 10 top-rated dish soaps and dug into them for this review, I uncovered a world of intriguing differences.

The Winners, at a Glance

This liquid dish soap from Palmolive was a clear winner. Its powerful surfactants (read: surface active agents) demonstrated excellent grease-cutting prowess; I employed the fewest swipes of a sponge to restore a sauce-splattered plate to squeaky-clean perfection. It was also one of the least expensive soaps per ounce that I tested, making it a powerful cleaner at a great value.

This petroleum-free, plant-derived dish soap from Mrs. Meyer’s Clean Day performed beautifully in my tests. It demonstrated a nearly identical level of grease-removal power as Palmolive and had a very respectable showing during my scrubbing test. The company specializes in plant-inspired scents derived from essential oils for its products, with tons of fragrances to choose from.

The Tests 

• Surfactant Test: Surfactants, short for “surface-active agents,” are the primary cleaning agents in dish soap that break up grease and food particles on dirty dishes. To assess each dish soap’s surfactant strength, I filled containers with a mixture of warm water and dish soap (at a ratio of one teaspoon of soap per cup of water). After gently agitating the mixture to distribute the soap evenly, I suspended a strip of brown paper (cut from a paper bag, which is designed to repel water) over the container, securing it so the end of the strip just touched the surface of the soapy water. I let it stand for one hour, then measured how far up the strip the water traveled. Surfactants in dish soap lower the surface tension of water, so strong surfactants allow the water to climb higher on the strip of paper.
• pH Test: Generally speaking, the more alkaline a substance is, the more effective it will be as a cleaner. However, basic solutions can damage and dry out your skin, so dish soap manufacturers try to balance cleaning power with gentleness on your hands. I was curious to see if a higher pH correlated with better performance and/or more abrasiveness on my skin, so I used a pH meter to measure each sample at a 1% solution.
• Scrubbing Test: I spread one tablespoon of tomato sauce onto identical plates and microwaved each plate for one minute until the sauce was cooked on. After leaving the plates to sit overnight, I used the soft side of our favorite dish sponge to scrub each plate with a measured amount of dish soap and 110°F water. I counted the number of strokes it took to remove the cooked-on food for each sample and assessed each plate after air-drying to see if any soaps left behind visible residue or a lingering scent.

What We Learned 

How Does Dish Soap Work?

The role of dish soap is to break up the coating of food residue and grease and loosen it from the surface so it can be rinsed off and removed. Like any soap or detergent, dish soap needs three kinds of energy to work this magic: chemical energy, thermal energy, and mechanical energy.

First up: chemical energy. To get dishes clean, you’ll need to use more than just water. If you’ve ever tried to get away with rinsing an oily sheet pan to clean it, you’ve probably noticed that a greasy film is still there after it dries. Since oil famously doesn’t mix with water, to remove grease, soap is required. 

The primary cleaning agents in dish soap are surfactants, short for “surface-active agents.” These are molecules made up of two parts: a hydrophilic (a.k.a water-loving) head and a hydrophobic (water-repelling) tail. When you mix dish soap with water, the water-loving end of the surfactant molecule bonds with the nearest water molecules, and the tail end pulls away from the water and latches onto the grease instead. This action breaks up the grease into little droplets that then become suspended in the water, making them easy to rinse away. In the process, surfactants also lower the surface tension of the water.

Since surfactants are the star players in dish soap, I wanted to learn more about them and how they work. I reached out to Dr. Brian P. Grady, Professor and Douglas and Hilda Bourne Chair in Chemical Engineering and Director of the Institute for Applied Surfactant Research at the University of Oklahoma. 

“Surfactant (in dish soap) is fundamentally what causes the dishes to become clean,” Grady says. He shares that there are generally two kinds of soils on dishes: liquid soils, like oil, and solid soils, like food particles. “For oily soils, the end result of applying surfactant is that the oil is dispersed in the water with surfactant around it. For food soils, it absorbs on the surface of the food and absorbs on the surface of the dish, getting in between them and weakening their bond. This allows mechanical action (scrubbing the dishes) to break them apart.”

Other chemicals in dish soap include enzymes that break down proteins and starches, and fragrance and dyes that provide scent and color. “There may be other ingredients in the soap, like conditioners for your hands, but surfactant is the active cleaning agent,” Grady confirms. “Scent and color are totally about consumer perception and have nothing to do with cleaning power.”

Then comes thermal energy. Washing dishes in warm water will re-liquefy solidified fats and soften solid food particles more effectively than cold water, making them easier to break up with the help of surfactants. But there’s no need to go too hot—the hotter the temperature, the more drying the water will be to your skin, and temperatures of 120°F and above can cause burns with prolonged exposure. (It’s never a bad idea to pop on a pair of dishwashing gloves to protect your skin from both water temperature and chemicals when washing dishes!) 

And lastly: mechanical energy. Even after soaking in some hot, soapy water full of surfactant, your dishes won’t be fully clean until you apply some elbow grease. The mechanical action of rubbing the dish soap back and forth across your dishes will help loosen the food particles and free them from the surface of your pots, pans, plates, and utensils. So, unless you’re popping them in a dishwasher, you’ll need to do some scrubbing to get your dishes fully clean.

Let’s Discuss Environmental Concerns About Dish Soap

As I dug into research about dish soaps and surfactants, I learned that surfactants are grouped into two categories: petroleum-derived or plant-derived. Conventional dish soaps (such as Palmolive, Dawn, Ajax, Gain, and Clorox) use surfactants and other ingredients derived from petroleum products. A new generation of dish soaps (like Mrs. Meyer’s, Seventh Generation, Method, Blueland, and 9 Elements) utilize plant-derived or “biosurfactants” instead, emphasizing environmental sustainability and biodegradability.

According to Grady, whether or not a surfactant is effective relies less on its source (e.g. plant-derived versus petroleum-derived) and more on how it’s formulated. “The molecule is the molecule, whether you make it from a petroleum base or from a plant base. You could formulate a dish soap totally with natural ingredients that would work just as well as one formulated with petroleum ingredients, except probably for foam-boosting.” (Sidenote: Another tidbit that Grady shared with me is that foam has nothing to do with dish soap effectiveness, despite what we all might think! If you see foam, you definitely have surfactant in the mix, but if you don’t see foam, that doesn’t necessarily mean that the surfactant isn’t there. Who knew!)

During my tests, it proved true that plant-derived and petroleum-derived surfactants can perform equally well (or poorly). The results of my surfactant test were divided between petroleum-based and plant-based products from top to bottom performers. The Palmolive (petroleum-derived) and Mrs. Meyer’s (plant-derived) samples had the strongest surfactants, pushing the water up the paper strip to reach 61 millimeters and 59 millimeters respectively. Ajax (petroleum-derived) came next at 46 millimeters, with Method and 9 Elements (both plant-derived) close behind at 39 millimeters and 37 millimeters. Clorox, Dawn, and Gain (all petroleum-derived) climbed to 37 millimeters, 32 millimeters, and 29 millimeters, and Seventh Generation and Blueland (plant-derived) had the weakest surfactants, reaching 29 millimeters and 24 millimeters.

Beyond how they are sourced, the biodegradability of dish soaps matters for environmental impact, too. “The biggest environmental concern is degradability,” Grady tells me. “All or almost all dish soaps are formulated so that the molecules are degradable in water treatment facilities. It’s not necessarily true that plant-based surfactants are more biodegradable than petroleum-based surfactants.” But, if your dishwashing wastewater isn’t going to be treated (for example, if you’re on a septic system), opting for a more naturally biodegradable dish soap with plant-based surfactants and without phosphates may be a safer environmental choice.

And, finally, there’s the environmental impact of packaging. All of the samples in this lineup except for one were liquid dish soaps that came in plastic bottles. (Yes, even the proudly petroleum-free dish soaps were packaged in…petroleum.) According to a recent report by the OECD, an intergovernmental policy organization, global plastic waste generation more than doubled from 2000 to 2019 to 353 million tons, and only 9% of plastic waste is recycled. To combat that waste, some companies like Mrs. Meyer’s, Palmolive, Method, Dawn, Seventh Generation, and Ajax offer large-format refills so you can reuse their smaller bottles or fill up another receptacle. (Those refill containers are also made of plastic, it should be mentioned, but at least they cut down on the quantity of individual bottles purchased.) 

As an alternative, companies like Blueland focus on the sustainability of both their product and its packaging. The Blueland dish soap in this lineup was a powder, rather than a liquid, and came in a reusable plastic-free silicone bottle. You simply shake the powder out of an opening in the lid onto a wet sponge to create a lather for dishwashing. While this soap didn’t perform as well as others in this lineup, if going plastic-free is your chief concern, it’s worth looking into companies like Blueland that offer aluminum or paper packaging, checking out a solid dish soap, or finding a local refillery. (Blueland was the only zero-waste-oriented dish soap I tested, so I can’t speak to the effectiveness of other brands.)

User Experience Mattered

In addition to a dish soap’s surfactant power and environmental impact, it should be pleasant to use. For some folks, scents make the soap more appealing, but fragrances shouldn’t be overpowering. I found the Ajax lemon scent and the Gain whatever-Gain-is scent to be very assertive. Mrs. Meyer’s lavender scent was pretty strong and, unfortunately, I’m not a lavender gal, so it wasn’t that appealing to me. But I do love Mrs. Meyer’s basil, honeysuckle, and lemon verbena scents, which I find noticeable but not overpowering, so there’s likely a scent that would work for anyone in their offerings. The Dawn and Palmolive samples had light, pleasantly “soapy” scents, and the Method, 9 Elements, and Clorox soaps were lightly citrusy. For folks who prefer soaps free of fragrance or dyes, Seventh Generation, Dawn, Palmolive, and Blueland offer unscented options (or come that way by default).

A soap that has good cleaning power but is still gentle on hands is another factor to consider. Very alkaline or basic soaps will clean effectively but will dry and damage skin more quickly than those with a more neutral pH. In my testing, the Gain soap had the most basic pH of 9.89, followed by Dawn at 9.78, and Method and Clorox both at 9.43. Most of the others, including my winners from Palmolive and Mrs. Meyer’s, had pHs between 8.44 and 9.09, making them more neutral and gentler on skin. The outlier in this group was 9 Elements, with an acidic (versus alkaline or neutral) pH of 6.24. This makes sense, as it was the only soap in this lineup to include vinegar as an ingredient.

But when it comes down to it, how quickly a soap can effectively clean a dish is perhaps the most important criterion of all. When I scrubbed identical stained plates with cooked-on tomato sauce, most of the soaps required 60 to 70 strokes with a sponge to remove the residue. Dawn and Clorox performed better, tying at 54 strokes each, and Mrs. Meyer’s was close behind, clocking in at 59 strokes. The Palmolive, however, sailed past the rest, requiring only 45 strokes to clean the plate—a whopping 38% faster. Cutting dishwashing time down by a third is an admirable outcome, in my opinion, and sealed this dish soap’s place in the top spot. 

The Criteria: What to Look for in Dish Soap

A great bottle of dish soap should have powerful surfactants that quickly break up grease and solid food particles left behind on dishes, reducing scrubbing time. It should be alkaline enough to be an effective cleaning agent, but not so basic that it irritates or damages your skin. It should have a pleasant but not overpowering scent for those who like scented soaps, and also come in an unscented, dye-free option for those who don’t. The soap should be 100% biodegradable and, ideally, offer large-format refill bottles to reduce plastic waste.

Our Favorite Dish Soaps

What we liked: This dish soap demonstrated the most powerful surfactants of my lineup, pushing soapy water 61 millimeters up a paper strip over the course of an hour. That surfactant power was evident in my scrubbing test as well, translating to the fewest strokes needed to get a sauce-encrusted plate perfectly clean. It has a light, pleasantly soapy scent that isn’t overpowering. It’s 100% biodegradable, and its pH of 9.09 makes it less harsh on skin compared to other samples, but it’s still effective as an alkaline cleaner. The bottle was easy to hold with its indented shape, and its cap was easy to flip open and snap closed without any drips. At $0.13 per ounce at the time of testing, it was also one of the most affordable dish soaps in the lineup.

What we didn’t like: The bright green color and soapy scent may not appeal to some consumers, but this dish soap is also available in a fragrance- and dye-free option. It is a petroleum-derived product and comes in a plastic bottle, so if environmental sustainability is your main goal, you might want to choose a different dish soap.

Key Specs

• Price per ounce: $0.13
• Scented: Available scented or unscented
• Surfactant source: Petroleum-derived

What we liked: This dish soap by Mrs. Meyer’s boasts surfactants that are nearly as powerful as those in the Palmolive soap, even though they’re derived from plants and not petroleum. It made a respectable showing in my scrubbing test, placing fourth out of 10 samples in the number of strokes it took to clean a dirty plate. The soap is dye-free and comes in a wide range of garden-inspired scents derived from essential oils. The pH is on the milder side at 8.83, making it gentler on skin, and the company’s dish soap formulas are biodegradable and cruelty-free.

What we didn’t like: Given that Mrs. Meyer’s line of products is all about “aromatherapeutic home keeping,” this brand does not offer an unscented option for folks who’d prefer to go fragrance-free. I also found the pop-up cap of the bottle pretty stiff and sometimes difficult to open and close. Though large refill bottles are available in some scents, all of the dish soaps are packaged in plastic, so it’s not completely eco-friendly. At $0.24 per ounce, it was on the more expensive side in this lineup, though not as expensive as some other soaps I tested.

Key Specs

• Price per ounce: $0.24
• Scented: Yes, only available scented
• Surfactant source: Plant-derived

The Competition 

Also Good

• Ajax Ultra Dishwashing Liquid Soap: This very affordable conventional dish soap ($0.10 per ounce) gave Palmolive a decent run for its money. It reached a respectable 46 millimeters in the surfactant test but did take 64 sponge strokes to clean the dirty plate. It is 100% biodegradable and does offer large-format refills. Its scent was very strong, however, lingering even after the plate was dry, and it does not come in a fragrance- or dye-free option, so it’s not for the fragrance-averse.

Not So Good

• Seventh Generation Dish Liquid Soap: This dish soap is focused on sustainability, using biodegradable, plant-derived ingredients that are USDA Certified Biobased and EPA Safer Choice certified. It’s available scented or unscented and large-format refill bottles are available. Unfortunately, its plant-based surfactants didn’t pack much power, reaching just 29 millimeters in the surfactant test, and requiring 71 strokes with a sponge to clean a sauce-encrusted plate. Though it is an admirably eco-conscious brand and formula, its performance fell short of my expectations for an effective dish soap.
• Dawn Original Dishwashing Soap: This nationally bestselling dish soap performed pretty well in my scrubbing test, requiring just 54 strokes to clean the dirty plate. Its pH of 9.78 was the second-highest in the lineup, making it a bit harsher on skin, but effective as a cleaner. It is available in a “free & clear” formula without fragrance or dyes and does offer large-format refill bottles. Though Dawn fell short in my surfactant test, reaching only 32 millimeters on the paper strip, its proprietary surfactants remain the most trusted to help rescue wildlife after oil spills.
• Method Gel Dish Soap: This plant-derived dish soap from Method looked sleek and smelled great but fell short in performance. It required the most effort of all the soaps I tested to clean the plate during the scrubbing test, clocking in at 73 strokes. It was a middle-of-the-road performer in the surfactant test, reaching 39 millimeters on the strip, and had a fairly high pH of 9.43. This bottle was also quite expensive, costing $0.78 per ounce. For a plant-derived dish soap option, you’re better off choosing Mrs. Meyer’s instead.
• Blueland Dish Soap: This dish soap was the only powdered dish soap in my lineup. To use it, you shake the powder out of its reusable silicone bottle onto a wet sponge to create a lather. I found the shaker-style bottle messy, as there’s no way to close the shaker slot, so the dry powder escapes onto surfaces over time as you tip the bottle. The soap performed the worst in the surfactant test, reaching just 24 millimeters on the strip, and I needed 64 strokes to clean the plate. It’s possible the standardized dilution I used for testing wasn’t quite right for a powder compared to a liquid dish soap, so if you’re committed to going plastic-free, this soap is still worth considering. It does, however, come at a hefty price tag–you’ll need to invest $18 plus shipping for the bottle and one refill initially, and the soap refills are $0.75 per ounce after that. The powder will last longer than liquid dish soaps, though, since you are providing the water.
• Gain Ultra Dishwashing Liquid Dish Soap: While this conventional dish soap was the most affordable of the lineup at $0.09 per ounce, it proved to be a “you get what you pay for” experience. It reached just 29 millimeters during the surfactant test, needed the third-highest number of strokes to clean the plate at 68, and had the harshest pH at 9.89. Its scent was very strong, bordering on overpowering, and it does not come in an unscented or dye-free option. If you really, really love the scent of Gain, then by all means, give this soap a try, but otherwise, there are far better options.
• Clorox Liquid Dish Soap: This conventional dish soap performed pretty well, requiring 54 strokes to clean the plate and reaching 37 millimeters in the surfactant test. Its uniquely shaped bottle was a bit awkward to hold, and its pH of 9.43 put it on the harsher end of the spectrum of the soaps I tested. Clorox does not offer large-format refills for its dish soap, so its plastic bottles are single-use. 
• 9 Elements Liquid Dish Soap: This plant-derived dish soap is unique for being “vinegar-powered,” utilizing acidic vinegar as one of its main cleaning agents. I didn’t notice a strong vinegar odor in the lemon scent, just a light citrus fragrance. It performed in the middle of the pack in the surfactant test, reaching 37 millimeters, but required 62 strokes of the sponge to clean the plate. I liked that its “EZ squeeze” bottle was mess-free and points downward, so you don’t need to flip the bottle to dispense the soap. Though it is branded as eco-friendly and uses minimal ingredients, 9 Elements does not offer large-format refills of its soap, making its bottles single-use. 

FAQs

What is the best way to wash dishes by hand?

According to a recent study by the University of Michigan, a “two-basin” method of manual dishwashing saves more water and is more energy efficient than the “running tap” method. To set up a two-basin system, if you have two sink compartments, fill one with warm water for washing and the other with cool water for rinsing (or use a separate tub or basin for the warm water and use the rest of the sink for rinsing). Add some dish soap to the warm water and scrub with a sponge or dish brush—this helps you use less soap than having to reapply directly to the sponge every few dishes. Start with the least soiled dishes first and change out the water when it gets discolored or messy from debris.

Are there environmentally friendly dish soaps?

Biodegradability is the main environmental concern with dish soap. Dish soaps are formulated to degrade in water treatment facilities, but dish soaps with plant-derived surfactants are more readily biodegradable than those made with petroleum-based ingredients. Our favorite plant-derived dish soap from this round of testing was Mrs. Meyer’s. Packaging is another environmental concern—the most environmentally friendly dish soaps offer large-format refills to cut down on plastic waste from single-use bottles, and brands like Blueland offer plastic-free, zero-waste products.

Does scent matter in dish soap?

Nope! Scent and color are extras that neither add to nor take away from the cleaning power of dish soap. If you like your soap to have a scent, Mrs. Meyer’s has the widest and best selection of options, but fragrance- and dye-free dish soaps will work just as well, depending on the brand. What really makes the difference in the effectiveness of dish soap is its type and formulation of surfactants.

Why We’re the Experts 

• Afton Cyrus is a food blogger, recipe developer, culinary instructor, and food writer and editor with a passion for baking. 
• She spent eight years as a test cook and editor at America’s Test Kitchen before becoming a contributor to Serious Eats in 2023.
• For this review, Afton measured how effective the surfactants were in the dish soap, tested their pH, and used them to clean dirty dishes. 
• To get insights into dish soap formulation, she interviewed Dr. Brian P. Grady, Professor and Douglas and Hilda Bourne Chair in Chemical Engineering and Director of the Institute for Applied Surfactant Research at the University of Oklahoma
• Afton has learned from the best how to execute rigorous and objective equipment testing protocols. You can see her meticulous approach to product testing in action in her reviews of coffee canisters, hand mixers, liquid measuring cups, fondue pots, and pressure canners.