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.

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

  1. Ive been cleaning with vinegar, water and castile soap for years and if you do it in the right order you do NOT get the white slick mess… I get a beautiful solution and it cleans wonderfully, no streaks eve on glass that the sun shines brightly through!

    • so do I; two table spoons of Liquid Castile in a 32 oz spray bottle fill it almost to the top with water…let it rest for a few minutes and add about 2 oz. of vinegar and it works great

  2. I have a question, I can use lemon essential oil, or any citrus oil, on the unscented Castile soap to make my own scent?

    • Hi Renae – Yes! That’s a great thing to do. Lots of fun!

  3. Would it change anything if I only used a couple of drops of soap to a four-cup mixture of vinegar and water?

    • Nope. The soap would be totally undone by the vinegar and provide no benefit whatsoever.

    • Hi T – When I wash clothes with the castile, I add vinegar to the fabric softener spot in my washer. Then it is only added during the rinse cycle. For dishes, if you wash with castile, I rinse in plain water and hand dry them. If you wanted them to drip dry, add another step of dipping them in a sink of water with a cup or so of vinegar in it in order to eliminate any hard water spots on the dishes.

    • Hi Cherie – Kleen Green does not list their ingredients, so I don’t know what’s in them or how they’d react with our castile. They give categories, but not specifics, which is kind of frustrating. You can try asking them about adding Castile.

  4. Regretfully, I didn’t know about this before washing our three cats in an ACV+Dr. B’s Baby Mild mix to fight fleas. Now all three cats are losing hair on their heads, where we applied the most of the mixture. I feel awful! It’s been about a week since the bath and we thought the greasiness would go away, like with other products, but the cats are still a little slimy. I’ve tried searching the internet, but can’t find an answer: how do we clean up unsaponified soap (especially from fur)?

    • Hi Molly – What you have with the ACV/soap combo is the original oils. Your cats are probably ingesting the oils that are left on their fur, and although they are organic, it still might not be best for their tummies in quantity. Washing your cats again with just the unscented Baby Mild soap will help tremendously.

  5. Thank-you, Lisa, for this VERY informative article! I recently had a contractor come in and change out the original 1960″s “orangey” trim in our little ranch style home with a clean, craftsmen inspired trim that’s painted white. Now, in the cleanup stage, I want to deep clean my original oak hard wood floors.
    I’ll take your advice and start with the Dr. Bronner’s Castile soap, then come back s e p e r a t l y with the vinegar in a one-two clean punch!

  6. Can unscented Dr. Bronner’s Castille soap be mixed with hydrogen peroxide at the same time?? Thanks!

    • Hi Laurie – Soap and hyrdrogen peroxide is another combination that doesn’t do well. Hydrogen Peroxide, or OH, is slightly acidic and in reacting with the soap will break down. You won’t get the antibacterial benefit of the peroxide. Best to use them separately. I’m currently working on a more comprehensive guide that addresses other combinations such as this one. It should be up soon!

  7. Hi Lisa
    Is that white film (salt residue) on the dishes safe to consume?
    Can I still eat from that dishes without rinsing them with vinegar?
    Thanks!

    • Hi Alona – Yes, it’s safe to consume. You don’t have to rinse the dishes with vinegar. That step is just for extra shine.

  8. I used white vinegar, water and Dr. Bronner’s peppermint castile soap mixed together to make an ant repellant because I did not have any peppermint essential oil around. And then I was taken aback by the resultant chemical reaction and found this article. The GOOD news is it worked great for my purposes. I sprayed it outside along the base of the house and in the grass. The ants were immediately stopped, and I had no fear of toxicity to plants or when my cat decided to roll in the grass because he liked the smell so much. So it may not be a good combo for cleaning, but it’s fantastic as a natural ant repellant.

  9. Thank you Lisa! Unfortunately, I didn’t see this until after I combined the two in my laundry load and found the white mess 🙁 If I followed the directions on the bottle, it clearly says to add the vinegar to the RINSE cycle but I was trying to save me the step… is there a way to get the white spots off of my clothes or am I going on a shopping spree?

    • Hi Dawn – I’m sorry that happened! What you have on your clothes is oil. Try giving them another wash but without the vinegar this time. If you happened to have Dr. Bronner’s Sal Suds, use that. It is slightly more effective at tackling spots.

  10. I have found that because I wash my hair with Dr. Bronner’s and then rinse with vinegar I get an oily tub/shower from the vinegar ‘unsaponifying’ the soap still hanging out in the tub. At least I assume that’s what’s happening. Am I the onlt one? And is there a way around this without having to clean my shower every time between washing and doing a rinse on my hair?

  11. Hi! Can you combine Castile Soap with rubbing alcohol to clean & disinfect? If so, what’s the ratio??

    • Hi Cristina – The benefit of adding rubbing alcohol to the Castile soap is negligible. However, it will not react as does the vinegar. If you would like to add alcohol, keep the concentration of it under 5%.

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