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.

260 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.

  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?


    • 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,

  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!

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