A Word of Caution About Vinegar and Castile Soap

Dr. Bronner’s Castile soap and vinegar can clean an entire house. They are effective, versatile, biodegradable and non-toxic. But the sole point of this post is to emphasize that these two should not be mixed directly. This is true for the Castile soap and any acid – any vinegar or lemon juice.

Since there have been several recommendations in online recipes and on TV to mix these two together, I want to address this topic. It’s not a dangerous combination, but it’s definitely moving in the wrong direction as far as getting things clean.

Here’s why.
In great part it’s due to the fact that vinegar is an acid and the Castile soap is a base. They will directly react with each other and cancel each other out. So, instead of getting the best of both (the scum cutting ability of the vinegar and the dirt transporting ability of the soap), you’ll be getting the worst of something entirely new. The vinegar “unsaponifies” the soap, by which I mean that the vinegar takes the soap and reduces it back out to its original oils. So you end up with an oily, curdled, whitish mess. And this would be all over whatever it was you were trying to clean – your laundry or counters or dishes or whatever.

Check out this picture of Dr. Bronner’s Peppermint Castile soap mixed directly with distilled white vinegar:

Dr. Bronner's soap mixed with vinegar

It doesn’t matter what else is in the solution, or in what order you combine them. If you end up with the soap and the vinegar in the same container, this reaction will occur.

The mom in me has to point out that if you have kids who wonder about the purpose of science class in “the real world”, you can show them this little reaction. Of course, drinking milk and orange juice at the same time will also point out why you should know your acids from your bases.

So, for cleaning, there is a better way. Use the soap to clean and the vinegar as a rinse agent.

One common complaint with using the Castile soap, especially on hard or shiny surfaces is that it leaves a film behind. This film is caused by the soap reacting with minerals in the water. It is not actually soap itself left behind, but rather certain salts. When this builds up on sinks and tubs, we call this soap scum. Vinegar is a great way to cut this. So after you’ve handwashed your dishes with Castile soap and rinsed them, dip them in a sink of vinegar water. Or after you’ve wiped down the sinks and tubs with soapy water, rinse, and then spray with a vinegar solution (about 1 cup vinegar/quart water).

I’ll give more time to windows later (one of the things I actually really enjoy cleaning), but briefly, for dirty exterior windows, spray them with my Castile soap solution, wipe them with a chamois, then spray them with vinegar and squeegee. Works great! Better than Windex.

Also, on the hair, if you do not have our Citrus Hair Rinse, but just want to use vinegar or lemon juice, rinse the soap out of your hair first. Then apply the vinegar or lemon juice.

So Dr. Bronner’s Castile soap and vinegar are a fabulous one, two punch. One after the other. Not at the same time.

As a sidenote: This issue does not apply to combining Sal Suds with vinegar. Sal Suds, as a synthetic detergent, has a completely different chemical makeup and does not react with the vinegar in the same way. Vinegar would even add more degreasing power to the mixture.

451 thoughts on “A Word of Caution About Vinegar and Castile Soap

  1. Can you use vinegar in the rinse cycle of the wash if you are using Castile soap?

    • Hi Jan- Yes, at that point in the cycle, the Castile soap has been rinsed out. The vinegar doesn’t have a chance to interact with it.

  2. Hi there. I just got my hands on a sample pack of the castille soaps. Super excited. I just read above about the common complaint of the “film” that people notice sometimes as a result of the castille soap reacting with minerals in water. Would it help if I used distilled water?

  3. Does anyone if Castile soaps can be used on stained concrete? I do not want the shine to dull, but I, looking for a natural way to clean my newly stained floors.

    • Hi Cynthia- Those sound beautiful! Castile does a great job on floors, but it does react with hard water to leave a white mineral deposit, which is especially apparent on concrete. Sal Suds doesn’t have this reaction. Dilute 1/2 Tbsp. in 3 gallons of water. If you have any concerns, spot test in an inconspicuous area first.

    • Thank you. I bought a bottle yesterday, I look forward to trying it out.

  4. We have been Dr Bronners fans for years and after recently remodeling our bathroom have discovered that our favorite peppermint soap is badly staining our off-white porcelain tiles an orangey-yellow. The tile is egg shell textured but are not porous.

    To be clear this is not the usual white film many people report but a distinct amber stain anywhere the soap has touched in its undiluted form leading to drip stains, splatters and runny lines down our shower walls.

    A “Natural” bathroom cleaner purchased from Wholefoods has lightened the stains only slightly and I’m at a loss as to how to remove it completely.

    If anyone has come across something similar I’d love to hear any solutions.

    • Hi Andrew- I’m terribly sorry to hear this! It’s a new one to me. Have you tried scouring with baking soda or sprinkling baking soda then spraying with vinegar and scouring?

    • Thanks for your reply Lisa.

      We did try baking soda with no success but vinegar (or lemon juice) was our next plan of attack so I will try that tonight and hopefully the stains will fade.

  5. So I found this thread *after* mixing the soap and vinegar in the laundry. 🤦🏼‍♀️ Now the greasy film is splattered all over my husband’s work shirts. Help!! What’s the best way to get it out?

    • Hi Christen- I am so sorry this happened to you! Vinegar can be added to the rinse cycle, in which case it doesn’t have a chance to interact with the Castile, but as you’ve discovered, those two ingredients don’t play well together. To remove, pre-treat the spots with Sal Suds and soak before laundering. For a how-to, refer to this post: http://www.lisabronner.com/pretreating-laundry-stains-with-dr-bronners/.

    • Thank you Lisa!! Praying this does the trick.

  6. Hi lisa,

    for the laundry, (probably a stupid question but i’d rather ask than have a bubble tsunami situation in the laundry..) for front loaders, would you half the measurements?

    • Hi Jenny- Coming from someone who has experienced a bubble tsunami or two, it’s better to ask! The amounts differ for a standard or HE machine. For a standard front-loader, use 1/2 cup Castile soap. If you have hard water, add 1 cup vinegar in fabric softener compartment. Halve these amounts in HE machines.

    • Hi Lisa
      I would like to change my laundry detergent to your product. If I have it right and my math is correct:
      I have an He front load washer. If I add 1/4 cup the Pure-Castile soap to Laundry, the container I buy for $25 (946 ml) will do 16 loads. Isn’t that kind of expensive? Please let me know. Love your product for all other uses.

    • Hi Bill- That is the correct amount for an HE washer. You could check out the Dr. Bronner’s Sal Suds which makes a slightly more fantastic laundry wash. Use 1 to 1 1/2 Tbsp. (15-22 mL) for a large load in an HE machine.

  7. I am interested in buying dr bronner’s sal suds to make my own cleaner. Unfortunately,while looking at the ingredients list I see it contains sodium lauryl sulfate,a known skin irritant.Per Mercola’s website, I see that “although SLS originates from coconuts, the chemical is anything but natural. The real problem with SLES/SLS is that the manufacturing process (ethoxylation) results in SLES/SLS being contaminated with 1,4 dioxane, a carcinogenic by-product”
    Here is another website explaining this:
    Where exactly does the sodium lauryl sulfate come from?
    Thank you.

    • Hi Ann- It’s great that you look closely at ingredient lists! The Dr. Mercola article lumps together SLS and SLES, which though related, have significant differences. SLES is the only one of the two that undergoes ethoxylation, which is the process that produces the carcinogenic byproduct 1,4 Dioxane. SLS does not contain a nitrosamine group and therefore cannot have the carcinogenic concern. SLS is one of the most benign synthetic ingredients available. The Cosmetics Safety Database gives it a 1-2 in their hazard rankings (https://www.ewg.org/skindeep/ingredient/706110/SODIUM_LAURYL_SULFATE/#.WXYgvoTyuUk), which is almost the lowest (i.e. least hazardous) ranking they have. SLS’s only drawback is that it can be drying to skin, which is why it shouldn’t be in personal care products. If you’re looking for a natural product, our Castile Soap is made entirely from pure plant oils and makes an excellent all-purpose household cleaner. For a deeper dive on SLS, refer to my blog post on it: https://www.lisabronner.com/there-is-no-cancer-risk-from-sls-sodium-lauryl-sulfate/.

    • You sure can! You don’t want an acidic solution, such as vinegar, on marble as it can etch. But both the Castile soap and Sal Suds are alkaline, and when diluted have a pH near neutral, so they are safe.

  8. I just purchased some of the liquid castile soap to use for hand soap and dish soap. Problem is, they are both so runny. I have read reviews online where you can add salt to the soap/water mixture to thicken, but it turns my mixture to curds. (I have tried both Table Salt and Sea Salt with no success). Is there another way to thicken the mixture?

    • Hi CC- Both table salt and sea salt contain trace minerals, which I suspect caused the curdling. Pure salt, labeled as Kosher Salt or Pickling Salt, will have a slight thickening result – but probably not as much as you’re looking for. Instead, try a foaming pump with 1 part soap to 3 parts water, or our Organic Sugar Soap – which is naturally thicker – for hands, face and body – one on dishes though. Refer to our “cheat sheet” to really put the Castile soap to work: https://www.lisabronner.com/dilutions-cheat-sheet-for-dr-bronners-castile-soap/

    • The only people I trust to give me undiluted organic Castile Liquid is http://www.countryrosesoap.ca. Country Rose Soap Canada.

      Their Castile is not runny either.

      Certain essential oils I noticed make it way thicker too which is probably destroying the Castile. I believe we are not supposed to use any acidic ones, like lime, no vinegar, … I was told to mind the ratio of any additives to Castile: i.e. 2.5% additives (e.g. combination of essential or carrier oils, water, etc.) to 97.5& Castile Liquid Soap. Anything more than 2.5%-3%, I was told, will damage the composition of the Castile and it will start to separate its components.

      Lisa will know more about all this.

      Lisa if you would give us a list of essential oils that MAKE a gooey mess of Castile Liquid Soap – so that we may avoid adding these when making hand, body, or shampoos – it will be greatly appreciated by all in this group, I am sure.

    • Hi Antoinette – You’re very savvy to watch out for chemical reactions in DIY mixtures. I wrote an overview of that exact topic, regarding what you can mix with Dr. Bronner’s Castile soap: What Can You Mix with Castile Soap. Pure essential oils won’t react with our Castile soap. However, other plant extracts might. For example, lemon or lime oil does not react with Castile soap (which is how we have our Citrus Castile soap), but lemon or lime juice (because they’re acids) do react, and forms a goopy mess. As you said, vinegar reacts as well. Our Castile soaps dilute just fine in water, and my recommended dilution for an All Purpose Household Spray is just 1/4 c. of soap in 1 Qt. of water.

      I can’t vouch for how other formulations of castile soap may combine with other ingredients. I recommend reaching out to them specifically.

    • Hi Lisa, don’t understand how Lime and Lemon don’t react to Castile. Thought all acids react.

      You did not say what to mix up with Castile to make a 2 in 1 shampoo, i.e. to avoid the rinse with Vinegar.

    • Hi Antoinette – You are right in thinking that lemon or lime juice does react with the Castile. Juice, which is extracted from the pulp of the fruit, is acidic and water based. Lemon or Lime oil, on the other hand, is extracted from the peel of the fruit, doesn’t have much of a pH because it is not water-based. It does not react with the Castile.

      A 2-in-1 shampoo isn’t really possible with a true soap like Castile. You see this feature in detergent based hair care, and it has to do with the concept of different polarities of different types of molecules – which can then have a cleansing component side by side with a deeper conditioning component. I don’t have my head wrapped around all that enough to explain in more detail. If another reader has that info handy, chime in please.

      For a milder wash, with less need to condition, try our Organic Sugar Soaps. Or, some people have had success with adding coconut milk to the soap. This will reduce the ability of the soap to clean, but it does make it more conditioning. I am pulling these ideas from the Definitive Guide to Washing Your Hair on the Dr. Bronner’s blog.

  9. Slightly unrelated but I couldn’t find a place on the Internet to ask this: Should I rinse my floors with clean water after I mop them with a Bronner solution?

    • Hi Sean- If you use the ratio I recommend (1/2 cup Castile soap to 3 gallons of hot water) and a good mop (I like microfiber), no you do not need to. At this great a dilution, the soap is going to grab the dirt on one side and the water on the other and the mop is going to carry them away.

  10. Hi there, what’s the best scent for laundry that will stay on the clothes? Thanks!

    • Hi Christine- The scents in our Castile soaps come from natural essential oils and won’t stick to and linger on clothing like a conventional laundry detergent or fabric softener – and that’s okay. It takes some time to get un-used to scented laundry, but those fragrances, which latch quite firmly onto fabrics, are often the worst offenders as far as toxic content. (You can read my rant on fragrances in my post, “Changing the Smell of Clean”: http://www.lisabronner.com/changing-the-smell-of-clean/.) To scent clean clothes and linens, place sachets in drawers and cupboards. Some people opt to add a couple of drops of essential oils to a wool dryer ball for scent. I recently come across Trader Joe’s lavender dryer sachets, which are filled with natural lavender and just get tossed in the dryer. You could even make your own.

    • “Some people opt to add a couple of drops of essential oils to a wool dryer ball for scent.”

      Do you know if the essentials oils might come off on your fabrics, since they aren’t really diluted?

      And do you think putting essential oils into the dryer in any form constitutes a fire hazard, since they are flammable? Not sure if the dryer would be hot enough (even on a high setting) to make this a concern…

    • Hi Beth – I sheepishly have to admit that I had not considered the idea of the flashpoint of essential oils in the dryer. I’m so glad you brought it up. I don’t use them there myself, but I don’t want to point others in the wrong direction. I just did some research, and the flashpoint of most essential oils is above the highest setting on a dryer, but there are some common essential oils, like citrus, that are not. There still would need to be an ignition source, but a really good spark theoretically could provide that. Again, thank you for bringing this idea up. I’m going to scan through my comments and amend them to state that essential oils in the dryer is not a good idea.

  11. I’d like to try Dr Bonner’s for my laundry. However I have read that using vinegar in the machine will damage the rubber seals. Is it essential to use vinegar? Can I just use the soap and dilute it or mix baking soda with it. Please let me know.

    • Hi Bill- No, you do not need to use vinegar in the laundry. If you have hard water, I recommend using Sal Suds in the laundry, 2-3 Tbsp. for a large load in a top loading washer. Use half these amounts for HE washers. Sal Suds is slightly more effective at stain removal and rinses clean, even if you have hard water. If you like, you can add a 1/2 cup baking soda (1/4 cup for HE washers) in the wash cycle for a particularly soiled load or extra whitening. For the record, I use vinegar in my washer periodically and haven’t noticed any damage to the rubber seals.

    • “I recommend using Sal Suds in the laundry, 2-3 Tbsp. for a large load in a top loading washer. Use half these amounts for HE washers.”

      Do you recommend diluting Sal Suds in a bottle in your laundry room, simply for easier pouring? (I.e., when I measure out a tbsp or so, the Sal Suds are so thick, it is hard to measure and pour completely off the measuring spoon.)

      Also, I figure this might be a good way to add (and dilute) essential oils I want to use in the laundry. I suppose the Sal Suds would need to be diluted with distilled water, as opposed to tap water, to avoid molding?

    • Hi Beth- I know just what you’re talking about. With my top-loader, I hold the cup under the filling stream to clear out the Sal Suds. It’s perfectly fine to pre-dilute, just adjust the amount used at an equal rate to your dilution. For example, if you dilute Sal Suds by 50%, then double the amount used per load.

  12. Hi, I’m trying to make homemade shampoo, but my mixture separated into very oil curdles. I followed a basic recipie with castille soap base, and added distilled water, oils and some citric acid as preservative….I also put in a bit emulsifier…then it turned into mayonnaise 😳. Is there anything else I can do to salvage it ? Thanks

  13. I mixed vinegar and soap with my precious expensive Young Living cleaner and lemon essential oil….how do I re clean my floors to get the film off?! Never mind that I’m devastated that I just wasted a whole bottle of my homemade cleaner (crying) but my floors are filmy and sticky and I’m ocd and can’t go
    To bed lol. I’ve already steam mopped twice! Help! Please. Thanks!

    • Hi Jessica – Oh no! I’m sorry to not see your comment earlier, as that is certainly the kind of thing to keep one up at night! Mopping your floors again with the Castile soap should pick up any remaining oil. You’ll want to use 1/2 cup of soap to 3 gallons of hot water.

  14. Do you recommend Dr Bronner’s castille soap for a base for shampoo. I’m not sure if that’s what is washing my hair color out or if my EO’s are to high in ph.

    • Hi Debbie- Yes, you can wash your hair with the Castile soap, but not color-treated hair. The alkalinity of the Castile soap opens up the hair follicles, where the color resides. Colored hair needs acidic products only, and soap, by nature, cannot be acidic. Only detergents (shampoo) can be.

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