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.

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

  1. Hi Lisa! I love your blog. I have been using diluted Dr. Bronner’s peppermint soap on travertine floor to deter pests since most don’t fancy peppermint oil. Will this cause any problems with a travertine floor?

    Thanks Lisa!

  2. Hi i am having hard water and due to this i am getting skin problems. one of my friend recommend me to use castilie soap. but i dont know does castilie soap leaves any residue behind on my skin after showering with hard water.
    if anyone have any suggestion or any helping idea pls let me know i will be really grateful for it.
    thanks

    • I’m not connected with this company, I’m just a consumer. I have very sensitive skin and after trying a lot of soaps, both natural and commercial, I found one that this bar soap is so mild that I can even use it on my face. It doesn’t dry out the skin. The soap I use is Vermont Soapwork’s Organic Unscented with Cocoa Butter and Oatmeal Bar Soap. I does not leave a residue on the skin and it also works as wonderful shampoo bar that gives my hair body and leaves my hair shinny. Hope this helps you.

  3. Hi Lisa, I’ve recently begun making my own body wash using castile soap in combination with a few other ingredients. I decided today that adding apple cider vinegar would probably do a good thing, however, it immediately curdled. Having already added most of the other ingredients, I tried to salvage the body wash by removing the curdles. Do you think it’ll have an effect on my skin if I use it? If so, how will it affect my skin?

    Thanks!

    • Hi! I just did the same thing! In hopes of creating a ph balanced body wash since in the past I’ve tried using bonner’s by itself and my skin went nuts. I usually use those foaming pumps and mix a small amount of soap with water, say may a 1:10 soap to water ratio. Great for hands but thats it. So know I have this curtled mixture of soap, water, aloe and acv in my pump bottle. I tried it and it still foams when I pump it! And when I washed my hand with it, it was actually kind of nice! The coconut oil used to make the castile soap actually gave a nice layer of moisture, but not a greasy one! So, I will let this sit over night and see what it is like in the morning! I may need to shake it every time I use it, but we may be onto something here! My only worry now is that is is safe. I’ll try to let u know what happens!

    • There’s no way to re-saponify the soap once it’s been un-saponified. Did either of you find something that worked?

  4. Hi Lisa,
    Great post! I was doing the exact same mistake, which I have fixed already.
    Thank you very much for writing about it!

  5. This is great, thanks. I don’t clean with the two as a unit, but did suspect something was happening when I’d feel a residue on my skin in the shower. Thanks for this. Didn’t realize you had a blog, but you’ve definitely got a new reader now. 😉

  6. I have no problem with mixing these. If you do it in the right order they don’t react and the soap doesn’t curdle. I end up with a very clean, steak free, cleaner.

    • I’d love hear another way, Andrea! Can you share the order you mix the ingredients? Perhaps you’re using baking soda which reacts with the vinegar before the soap hits it?

      All the best,
      Lisa

  7. I wanted to know have you ever mixed your Dr. Bronners peppermint pure castle soap with Aritha & Shikakai Indian powder? Or can it be done? Thanks Toni

  8. Hi Lisa, I wanted to know have you ever mixed your Dr. Bronners peppermint pure castle soap with Aritha & Shikakai Indian powder? Or can it be done? Thanks Toni

  9. Good article! I would think Dr. Bronner’s liquid soap already has a slight ph “neutralizer” in it with the citric acid they add so I wouldn’t think a straight vinegar (very acidic) rinse would be necessary with it generally. It would depend I’m sure, but it couldn’t hurt to try I guess. Now for some homemade bar soap shampoos, which tend to have high ph like homemade bar soaps, I would probably try an apple cider vinegar rinse (4.25) instead of a straight vinegar rinse (2.4) at first. I’m sure it would depend on the water type, hair build up for shampoo bars, etc. though.

    • Hi Rowe – You’re right on with the citric acid. Each batch of soap is tested and the right amount of citric acid is added to bring the pH down.

  10. Hi, I was just trying to reduce the ph of my Dr Bronners Rose with my ACV hair rinse mix. I put equal parts together, checked the ph (which had not lowered) and all of a sudden the mix changed to a lovely smooth cream! Has this got any use like shaving cream for my hubby? I have since read that you can’t alter the ph of Bronners! Although I love using Bronners for cleaning house and body, I have read that ph of skin and hair is more acidic, so not sure if I should be using it to wash with?

    • Hi Jennifer – You basically have the original oils that are used in the soap: coconut, olive, palm, hemp, jojoba. Since I regularly shave with coconut oil, I don’t see why not! You may have just solved this quandary for others who have ended up in a similar situation. Let me know how it goes if you try shaving with that concoction.

  11. Hi Lisa, thanks for the reply! My hubby used it to shave with this evening, he really liked it and his skin was nice and soft afterwards. I must add that it smells great: My hair rinse is: Fresh Rosemary & Sage simmered in water, strained and when cool added ACV, few drops of Ylang Ylang to negate the smell of vinegar. I’m storing it in the fridge as not sure what the shelf life will be!

    • Hi Jennifer – That Hair Rinse sounds great! And how fantastic to have finally found a use for the unsaponified soap! If you look through comments above, that has been a very common quandary.

    • You don’t need to worry about the smell of the vinegar because it will disappear as your hair dries.

  12. This is the exact result I had when mixing the two today. So basically I “cleaned” my shower today for nothing bc they cancel each out. 😞😞

    Wish I had read this before I made my mix!

    • Hi Laura – Bummer! I know that’s frustrating. Don’t give up!

  13. Just jumped over here from the Kitchn where a similar discussion is going on!

  14. Question– I make my own liquid soap with coconut oil and potassium hydroxide, and then use it in a recipe I have for liquid laundry detergent, which includes vinegar. Would this be true for other liquid soaps, or just olive oil-based liquid soaps?

    • Hi Jami – I’ve only tried this with our soap, but the theory would be the same. I would imagine vinegar would “unsaponify” your soap as well. You can try it out by taking some ofyour soap and adding a bit of vinegar. See if it forms those clumps.

  15. Great post! Does mixing with lemon essential oil have the same effects?

    • Hi Grizzy – No, using lemon essential oil would not have the same effect since it is not an acid. That would be a nice additional scent!

  16. I know you do not recommend mixing vinegar with Castile Soap. Is there any small amount of Vinegar that may be added to Castile Soap that will not affect the sponification?

    There is a claim: (see Note: & PLUS:)

    1 cup (235 gm) baking soda
    3 tbsp (45 ml) castile soap
    1 tbsp (15 ml) white vinegar

    Directions:
    Mix your baking soda, castile soap, and white vinegar in your container. (I like to add the vinegar last, so I can see everything bubble up!) Then add your essential oils and stir. (Or mix it up with your fingers!)

    Note: Using too much vinegar with castile soap can “unsaponify” the soap, but using the small amount in this recipe is fine.

    PLUS: Good News! The small amount of vinegar used in the recipe is not enough to affect the saponification of the Castile Soap.

    Is this claim true? Will this small amount of Vinegar NOT affect the saponification of Casrile Soap?

    • Hi Mrs. T – This is an interesting one because it is basically a race. Which will react faster with the vinegar:the baking soda or the soap? From my observations of doing this, it looks like it does react faster with the baking soda, so give it a go. I was already predisposed to think it might because Karen Logan, in her excellent book “Clean House, Clean Planet” has a soft scrub recipe that includes this combo, and she’s never missed in any of her recipes. Thanks for bringing this up!

  17. I have used 1/4 cup of liquid soap and 1/2 cup of white distilled vinegar in my laundry and cold water with great success. I don’t have it premixed, I just add them separately to the water in the machine and my clothes are really clean. I’ve been so pleased with it, that I’m surprised to read this. Am I doing something wrong?

    • Hi Aimee – The agitation of the machine and the water goes a long way to lifting dirt from clothes. Take this combination you’ve mentioned and combine it in a bowl, and then but something greasy on your hands like olive oil. Try washing it off with the solution. I think you’ll find that your hands remain greasy. The same would be true for grease on your clothes.

  18. Hi. I just did this and googled it because I didn’t know what happened. I made face cleaning clothes and used the same tbsp for the soap, and then the vinegar directly after! The face wash has water, dr. Bronners soap, vinegar, witch hazel, and tea tree oil in it. It feels like it cleaned my face. Should I toss it and if so what can I use in place of the vinegar.

    • Hi Jesse – Depending on your ratios, you might have had some soap left in it or some vinegar or the mechanical action of the liquid and cloth may have cleaned your face. All that to say, the soap and vinegar combo is not helping this solution, although the cloths might have worked despite them, but not as well as they would work without them. I’d leave the vinegar out of this combo and it should be just fine.

  19. I have very hard water and a copper sink. So when I wash dishes with diluted castile, my dishes have a greasy film on them. I cannot rinse them in vinegar because acids destroy the patina on my sink…..so my question is, is the film on my dishes safe for us to eat from and safe to drink from the glasses?

    • Hi Jaci – The hard water film is safe. It’s just unsightly. If you want to give our Sal Suds a try, it was specifically formulated to work flawlessly in hard water situations. It’s very clean rinsing. No vinegar needed.

  20. Very much agree with what Lisa has said here. I have an all-purpose cleaner recipe that I use and the recipe calls for using a little bit of liquid castile soap. I tried Dr. Bronner’s in the past, but ended up with an oily film on the top of the cleaner. I now use regular dishwashing detergent in the recipe, which works out much better.

  21. Thanks for the article. It helps explain my experience too with combining lemon juice with the soap in the hope of getting something more on the acidic side. The results were, needless to say, disappointing.

    I followed your link to the Citrus Hair Rinse and I noticed the potassium hydroxide in the ingredients and the note that none remains after the oils are saponified. It looks like there’s some liquid soap in the Citrus Hair Rinse, or am I misinterpreting the ingredients.? If there is, how does this work without the curdling and separating problems since lemon juice is the first ingredient?

    • Hi Dave – Very impressive! In all my years of answering customer questions, no one has ever asked me about that. You are absolutely right. We use soap to formulate the Hair Rinse and it’s not an accident. We utilize this reaction of the acidic lemon juice with the soap because in this way it holds in solution (emulsifies) the lemon juice along with the healthful oils without separation. So, we saponify and then unsaponify the soap. Just another one of the crazy things we do at Dr. Bronner’s.

    • Gotcha–thanks for the clarification! Clearly you have more success with that than I did with my little home experiment. 🙂

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