Is Dr. Bronner's Castile Soap Really the Only Household Soap You Need?

New York Times

4 days ago

Both soap and modern-day detergents clean by mixing with water to lower the surface tension and lift dirt away. When the solution rubs against a surface, such as dirty dishes, the dirt temporarily bonds to the solution, allowing you to rinse or wipe it away.
Andrea compared the cleaning power of Dr. Bronner's liquid Castile soap with that of two dish detergents, Seventh Generation Dish Soap and Dawn Platinum Dishwashing Liquid, which contain multiple surfactants to pull dirt from dishes and hands, as well as other ingredients such as viscosity adjusters, pH adjusters, and stabilizers to hold the formula together. (Though 'soap' and 'detergent' are often used interchangeably by both consumers and manufacturers, the Seventh Generation and Dawn liquids are both technically detergents, while Dr. Bronner's is a true soap.)
I also used Dr. Bronner's Castile soap as dish soap in my kitchen, scrubbing plastic storage containers with greasy film, an enamelware sheet pan with baked-on cheese, and stainless steel utensils with peanut butter and cream sauce residue. During my day-to-day testing, I applied a few drops of Castile soap to a sponge and cleaned dishes in my sink just as I would with dish detergent. Caroline Mullen/NYT Wirecutter Castile soap produces suds like dish detergent, but it left my hands feeling quite dry, and I had to rinse dishes more thoroughly than I would with dish detergent. Caroline Mullen/NYT Wirecutter During my day-to-day testing, I applied a few drops of Castile soap to a sponge and cleaned dishes in my sink just as I would with dish detergent. Caroline Mullen/NYT Wirecutter
The Dr. Bronner's soap did an adequate job of cleaning dishes, sudsing up similarly to the dish detergents. But it was less effective than the Seventh Generation and Dawn liquids, which did a better job of tackling grease and stuck-on food and required less rinsing for items to get clean.
The verdict: 2 out of 5 (somewhat effective with some shortcomings). Dr. Bronner's Castile soap will clean your dishes, but we found that the dish detergents were better at lifting grease and stuck-on food, and with their neutral pH, they're less likely to irritate your hands.
They are also less likely to leave a film of soap scum in the sink or on your dishes if you're not careful about thoroughly rinsing it off. That is especially true if you have hard water, since soap scum develops when saponified oils (like those in Castile soap) react with minerals in water.
In addition to surfactants, most laundry detergents also include other cleaning ingredients, such as enzymes, which target and break down proteins, fats, and carbohydrates that are otherwise difficult to remove with soap or surfactants alone.
Depending on the type of detergent and how you use it (such as in a machine versus hand-washing), a laundry detergent may also include other additives, such as polymers to suspend dirt before being washed away, optical brighteners and oxidizing agents to improve the appearance of fabrics, solvents to stabilize formulas, and disinfectants like bleach or other antibacterial agents.
We tested Dr. Bronner's liquid Castile soap as a hand-washing laundry detergent against Soak Laundry Rinse and Dirty Labs Hand Wash & Delicates Detergent, two picks from our hand-washing laundry detergents guide. Andrea tested how the cleaners removed stains by washing industrial stain monitors, professionally stained jersey-cotton swatches that allow us to directly compare cleaning power on substances such as red wine, pig blood, sebum, peat, and engine oil. We also washed three swatches of sebum-stained silk with each detergent and Castile soap and compared the results. We hand-washed jersey-cotton swatches that were pretreated with common stains. While neither cleaner eliminated the stains, Dr. Bronner's Castile soap (left) made little difference, while Dirty Labs Hand Wash & Delicates Detergent (right) significantly improved some stains. Andrea Barnes/NYT Wirecutter We washed sebum-stained silk with the three cleaners. From top to bottom: Dirty Labs Hand Wash & Delicates Detergent, Soak, and Dr. Bronner's. The detergents almost returned the sebum-stained silk back to its original luster, while Dr. Bronner's soap made almost no difference. Andrea Barnes/NYT Wirecutter We hand-washed jersey-cotton swatches that were pretreated with common stains. While neither cleaner eliminated the stains, Dr. Bronner's Castile soap (left) made little difference, while Dirty Labs Hand Wash & Delicates Detergent (right) significantly improved some stains. Andrea Barnes/NYT Wirecutter
Dr. Bronner's Castile soap performed worse than either of our picks. It lifted significantly fewer stains on the stain monitor than the Dirty Labs detergent, our pick for washing stained delicates. The Dr. Bronner's soap also left the sebum-stained silk looking rather gray compared with the samples we washed with the Soak and Dirty Labs detergents.
The verdict: 1 out of 5 (ineffective with disqualifying shortcomings). Dr. Bronner's Castile soap was far worse at lifting stains than the hand-wash laundry detergents we tested. Vigorous scrubbing or very hot water might improve its performance, but we don't recommend trying, since they may damage delicate fabrics you would typically wash by hand, such as silk, lace, cashmere, and wool. Hand-wash laundry detergents like Dirty Labs Hand Wash & Delicates Detergent and Soak are gentle on fabrics and have proven stain removal abilities.
Like dish and laundry detergent, all-purpose spray cleaners work by lowering the surface tension between the dirt or liquid you're removing and the liquid of the cleaning solution. Dirt, grease, and crud become suspended in the solution and can then be wiped away with a cloth.
I tested Dr. Bronner's liquid Castile soap as an all-purpose cleaner by diluting it according to package instructions and comparing its effectiveness with that of the top pick in our all-purpose cleaner guide, Clorox Free & Clear Multi-Surface Spray Cleaner. I used it on sriracha and toothpaste that I had left to dry on glass, as well as on smeared butter and ricotta on stainless steel. I cleaned the messes with both sprays using a microfiber cloth, paper towels, and a cotton rag. We tested a diluted Castile soap solution on (clockwise from top left) dried sriracha and toothpaste on a glass table and ricotta cheese and butter on a stainless steel fridge. Caroline Mullen/NYT Wirecutter
The Dr. Bronner's soap and the Clorox all-purpose cleaner both cleaned those surfaces, although Dr. Bronner's left behind more streaking and residue and required an extra buffing-dry step to get the surfaces fully spotless. Both cleaners were effective and required the same level of soaking (spraying and leaving the solution to sit) and scrubbing action to remove the dried substances. One major drawback to using diluted Castile soap as an all-purpose spray: Overspray not immediately wiped up leaves behind residue. Caroline Mullen/NYT Wirecutter
The verdict: 2 out of 5 (somewhat effective with some shortcomings). As an all-purpose cleaner, diluted Castile soap worked about as well as our top pick when applied in small amounts. But you may need to worry about residue and streaking.
A few things can help to prevent those issues: Use the smallest amount possible, which is easier to fully wipe off than a heavy spray. Wipe up overspray immediately, or it may leave behind specks of soap scum, which I noticed were particularly visible on stainless steel. Use a microfiber cloth, rather than a paper towel or a cotton cloth, as the tiny fibers of a microfiber cloth are more effective at buffing away residue.
I found these extra steps to be enough of a deterrent that I wouldn't opt for diluted Castile soap as an alternative to Clorox Free & Clear Multi-Surface Spray Cleaner. When I reach for an all-purpose cleaner, I'm usually quickly wiping something down, such as kitchen appliances or countertops, and worrying about residue eliminates Castile soap as a replacement.
Neither Castile soap nor Clorox Free & Clear Multi-Surface Spray Cleaner is a disinfectant, though with scrubbing and wiping or rinsing, either cleaner can remove pathogens. For disinfecting, we recommend using Clorox Clean-Up Cleaner + Bleach for killing pathogens such as bacteria or viruses.
There's a misconception that cleaning products made from synthetic ingredients may be more irritating than those made from natural ones. Depending on their formulations, detergents and Castile soap alike may be harsh for your skin, particularly if you have underlying skin conditions.
In fact, due to their alkaline pH, Castile soaps may be more drying than some detergents, said Marisa Garshick, a dermatologist and assistant clinical professor of dermatology at Cornell University, since Castile soap is even more alkaline than most detergents. This is especially true if you use Castile soap straight from the bottle without diluting it, for instance, as a dish soap, though some formulations, like Dr. Bronner's Unscented Pure-Castile Magic Soap, may include unsaponified fatty acids to help minimize irritation.
Whether you're using a detergent or Castile soap, Garshick recommends wearing gloves when cleaning by hand or washing off residue, and applying moisturizer afterward.
People with eczema or sensitive skin should be especially cautious when trying any new product. And keep in mind that any scented cleaner could be potentially irritating to people with allergies, respiratory conditions, or fragrance sensitivities.
If you are considering health and safety when looking for a cleaning product, note that 'natural,' 'non-toxic,' 'eco-friendly,' or 'clean' claims on labels are unregulated and may mean different things to different manufacturers. Voluntary third-party certifications, such as the EPA Safer Choice certification, UL Ecologo, or Green Seal, may give more peace of mind, since they set criteria for product ingredients regarding human and environmental safety. Dr. Bronner's Castile soap contains ingredients that are certified organic, which means they adhere to the standards outlined by the USDA's National Organic Program.
After weighing performance and safety considerations, I don't plan to switch to Castile soap over my preferred dish soap, laundry detergent, or all-purpose cleaner. Its universal-cleaner promises are enticing, and it does perform adequately or well at some tasks, but for other purposes it can't compare to the best dedicated cleaners. I'll use the rest of the bottle I have on hand for quick wipe-downs in the kitchen and otherwise, but after that's gone, I'll repurchase my old standbys.
This article was edited by Katie Okamoto and Megan Beauchamp. Andrea Barnes contributed reporting. If you're sensitive or allergic to fragrances in cleaning, personal-care, or other products, there's a distinct difference you should keep in mind.
After 65 hours of research, testing 28 detergents, and 7 years of long-term testing, we found Seventh Generation Dish Liquid to be the best dish soap for most people.
We hand-washed vintage linens, cashmere sweaters, and delicates in a variety of detergents and soaps, and Soak came out on top.
Clorox Free & Clear Multi-Surface Spray Cleaner rids surfaces of grime and comes with the EPA's Safer Choice certification.
Tide's newest laundry detergent comes in a sponge-like tile that looks strange but is surprisingly powerful, even in cold water.
What I Cover
Caroline Mullen is a staff writer reporting on cleaning and organizing at Wirecutter. Though she's waging a constant battle against the dog hair and dust bunnies in her apartment, she's not willing to scale back on tchotchkes to make it easier. It also takes her two to three business days to complete a load of laundry—but she's made peace with that.