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.

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

  1. Great information! Thanks so much! I did not see anything (I could have missed it – if so, my apologies) that addresses if Dr.Bronners castile soap (I have the lavender) can expire or go bad. I think I have had this bottle for over 15yrs. We used to use it all the time for showers, then we have moved a number of times and it got “misplaced.” I just found it. yay? I have been wondering about using it for a shampoo, and have that info from all your responses in this post. I just don’t know if it can “expire” or go bad/spoil so that I should not use it. I hate throwing things away (which is likely why I still have it). :) Thank you so much!

  2. Hi Lisa, I was pretty aware of these reactions and the leftover mineral deposits that are endemic to cleaning with hard water and natural soap, however I am curious if you have heard this particular complaint that I heard recently. Somebody told me they have stopped using natural soaps on their body because these mineral deposits left behind clog skin pores and don’t let their skin breathe as it should. It seems rather far-fetched in my opinion, but curious if these deposits continue to be left on skin and build up over time.

    I have always used the Bronner’s citrus rinse to take care of this problem on my hair, but after packing lightly for Cambodia recently I skipped that step and while my hair had that weird waxy feeling every day I kind of enjoyed the somewhat “dry” feel of it. Is there any particular concern with leaving these deposits on your hair? Thanks so much for your continued dedication to Bronner lovers!

  3. Hi Melissa #1 and Oxana – Your questions are similar so I can answer them together. There is more to the vinegar/soap reaction than pH. Although honey and aloe vera are also slightly acidic, they do not react with the soap. You are welcome to combine them.

    Hi Melissa #2 – Because you are adding so much more vinegar to the amount of soap in this recipe, there is still a lot of unreacted vinegar to clean up the residue left by the soap’s reaction with some of the vinegar. But the soap is not doing you any favors here. I think you should leave it out. Or leave out the vinegar. One of them should step aside, though. You would not need to add a rinsing step if you are wiping off the surfaces with a damp dry cloth.

    Hi Antoinette – I’m glad you are reading the ingredient lists! We add citric acid to our soaps in order to catch any unreacted hydroxides leftover after the soap making reaction. These hydroxides are very strong, caustic alkalis which would be very damaging to our skin. Therefore, each soap batch is individually tested to determine the needed amount of citric acid (when dealing with botanicals, every batch can vary). The citric acid is added in such a way so as not to react with the soap before it reacts with the hydroxides.

    Hi YY – The pH of the castile soap is 8.9, which is not terribly high. I have not tried this particular combination for a shampoo, but I am intrigued. I have a beautiful aloe vera plant at home, and I will try combining it with the soap and seeing what happens. I did combine it with the soap to see if there was the same reaction as with vinegar, and there was not. However, I do not know if it would elminate the need for a rinse. If you try it out, let me know what you find.

    Hi Annette – The shelf life of the soap is at least 3 years. After this time, the strength of the essential oils may fade, lessening the scent, but the soap is still effective. If the soap does not smell bad, then it is good to go. I’ve heard many stories of people finding old bottles and using them just fine. If you would like to know the age of your soap, look for a number stamped on the bottle somewhere – not on the label. The first four numbers are a Julian date. The first number indicates a year (i.e. 9=2009) and the next three numbers are the day of the year out of 365 (i.e. 001 would be January 1). If you’d like, please send me the number and I would be happy to interpret it for you.

    Hi Christopher – The reason we see these build ups on our sinks is because we generally don’t dry them after each use. Therefore, the minerals that are dissolved in the water are just left on the surface once the water evaporates. If we were to dry the sink with a towel after each use, we would not see this. However, generally we do towel dry our bodies, and so the towels absorb the water, along with the minerals dissolved in them. They would not be left on the skin. Even if a person were not to towel dry after a shower, the amount of mineral deposits on the skin would be minute and would come off in day to day life. They would not build up. Regarding your hair, there is absolutely no problem with the waxy feeling if you are enjoying it. It is not deposits on your hair that you are noticing. Rather it is the pH of the soap causing the follicles on your hair strands to stick up rather than lying smooth. Therefore, the hair appears dull instead of shiny and the strands more easily tangle together and give that waxy feel to the touch.

    Please let me know if I can be of further help.

    All the best,
    Lisa

  4. Hello Lisa, Is there any chance in the future we will find Dr. Bronner’s castile soap in glass, refillable bottles?

  5. Hi Lisa!

    I have a recipe for a laundry detergent I would like you to look at to see if you think it would be effective — 1/2 c. super washing soda, 1/2 c. baking soda, water, 3/4 c. Dr. Bronner’s Castile soap and 20-30 drops of essential oil. Thank you for your time!

  6. Hi Lisa, so I must have some very ancient bottles of Dr. Bronner pure-castile soaps. I found another peppermint 4oz bottle. :) So the label ‘styles’ on both these bottles are very different. And both are different from what’s on your website. I cannot find any number on either bottle that is not on the label, and even the numbers I find on the labels, are mostly costs, addresses, phone numbers, temperatures. The 4oz label is paper, and the lavender 16oz is like painted on the bottle or something (can’t get a corner to pull off or tear off the label). Is it possible at one time, there was no expire or manufactured date put on the bottle? :) As long as you think nothing can hurt my hair (because of how old it is), I will give it a try. So wash with my old castile soap and then rinse with a solution of water/vinegar, right? :) Again, thank you! Love your website and blog!

  7. I make a homemade soft scrub that has Dr. B’s and vinegar and it works amazingly – it’s a staple in cleaning. It gets my sinks and tubs so clean. Maybe with the combination of the other ingredients, it’s okay? It has baking soda, water and EOs in it, too. It’s super creamy when I mix it, like cake frosting…

  8. I’m a big fan of cleaning with natrual products. However, vinegar on it’s own has caused a few.. well what can I say… staines and discolorations on the surfaces I am cleaning. I have read a lot on the internet in regards to mixing vinegar and castile soap. I’ll go away now and have a bit of an experiment. Love the blog!

  9. Hi Lorna – Refillable, yes. Glass, no. Many stores and co-ops across the country offer refill stations for our products. They order the soaps in 5 gallon totes with spigots on them. Call around to see if someone does this, and if not, suggest that they do! Glass is exorbitantly expensive to produce, store, and ship. Also, there’s a lot of risk of breakage and injury since the soap is something that most people keep in the shower.

    Hi Michele – The recipe looks pretty good, but I always like to caution about that washing soda. It is highly effective and is a good alternative to bleach. However, it is very hard on clothing and may wear them down more quickly. Perhaps use that as an occasional booster rather than for every wash. And maybe just for whites, or really dirty stuff.

    Wow, Annette! You may have some collector items there! We haven’t had paper labels in a long time and other one is silk screened. So we’re looking at 11 years at the most recent for the paper label and somewhere between 2003 and 2005 for the silk screened. And the lot coding started in 2005 as well, so we’re before then with that bottle. As long as the soap doesn’t smell bad (even if the essential oil scent has faded) and if it sudses up and seems to clean (put some oil on your hand and try to wash it off with the soap), then you’re good to go with it.

    Hi Kristen – Yes! I’ve made this up myself and here’s why it works – vinegar reacts faster with baking soda than with castile soap, so the baking soda is “using up” the vinegar and making that nice frothy foam before the vinegar has any effect on the soap. Did you get that recipe from Karen Logan’s “Clean House, Clean Planet”? Love that book.

    Hi James – Vinegar is unfriendly to soft stones such as marble, limestone, and travertine and will cause etching and discoloration. It’s all about the chemistry! Let me know what you find in your experiments.

    All the best,
    Lisa

  10. I saw a recipe that mixed Dr Bronners with salt in a laundry detergent. Any issues with mixing it with salt? Also, is mixing it with olive oil for a hand soap ok? Saw a recipe for that too. Thank you!

  11. If using Dr B’s in laundry detergent, should I use vinegar in the rinse cycle?

  12. Hi Lisa,

    I really enjoy your blog and have recently been switching over to all Dr. Bronner as I feel it makes for an easy transition into a “clean environment”.. I have already replaced cleaners with Bronner and vinegar with water solutions, laundry and so on. I haven’t noticed any scum build up as of yet but I think that’s because I just began. We have hard water here and I think that is why I’m having problems with introducing Bronner as my “shower care” .. I attempted to dilute pure castile soap with water in a bottle about 1:8 ratio.. I washed my hair with a pump and that felt okay but when I washed my body with it my skin felt waxy and kind of sticky feeling. Is this because of the hard water? Do you have any solutions? I also tried to do a coconut hair mask treatment and it didn’t matter how many times I washed my hair the oil just wouldn’t come out. Why is that? Would the other type of Dr. Bronner soap make a difference? Thank you for your time?

  13. Hi Omni – The soap wouldn’t react with salt. I haven’t done this, so if you try it, let me know how it goes. The issue with mixing the soap with olive oil is that the soap molecules are attracted to oil. (They’re also attracted to water, thereby bonding oil to water. But I digress.) So, the cleaning ability of the soap would be diminished because the soap molecules would already be busy holding on to the olive oil molecules.

    Hi Lori – With the castile soap in laundry, yes, add vinegar to the rinse cycle.

    Hi Carley – Personally, I don’t dilute the soap for my shower, and I use it everyday. If I’m wet, and my washcloth is wet, I consider that to be dilution enough. Put a small squirt on a wet washcloth and that’ll do your whole body. That might help with the afterfeel. Hard water doesn’t usually have that affect with the soap on your skin. I, too, did a coconut hair mask with the same result and found that I had used waaaaaay too much oil. I have long, thickish hair, and used 1 Tbsp. oil. After four washes (the last one with SAl Suds), I finally got it all out. However, just last week, I tried it again with just 1/2 tsp. of oil worked through my hair. Then I put my hair up in a bun and warmed it with the hair dryer. Then I let it sit for 10 minutes or so, and it washed out the first time with just castile soap, followed by the hair rinse. My hair was in great shape afterwards.

    All the best,
    Lisa

  14. Hi Lisa, I have a recipe for furniture polish/wood floor cleaner that uses Dr. Bronners and lemon EO. Almond oil and water. I noticed in your statement regarding Castile soap and vinegar or lemon juice should be avoided. Does the same apply to lemon essential oils??

  15. Hello, I know this thread is a bit old but I have an emergency question. I used ACV & the Peppermint Castile soap COMBINED on my private area and I haven’t been feeling the same, Im worried because your post says it causes acid and should not be mixed. the reason why I used the acv was because I was having severe stomach pain and heard it can help uti (I thought that’s what it was) and I always use the castile soap as a body wash. Please help, & NO RUDE COMMENTS PLEASE

  16. Hi Asia,
    Lisa may take a while to respond so since I get email notifications about this post I thought I would try to help.
    I know for certain for a UTI ypu can drink unsweetened cranberry juice to help get rid of it. I’m not sure about ACV but I would have thought you would need to drink it. Infection is internal so drinking plenty of water, cranberry juice and possibly the ACV (like I said before, not sure about that one) will flush your kidneys then your bladder and uterine tract.
    As for your private area all I can suggest is to keep rinsing with water and/or maybe a different soap until it feels back to normal.
    Hope this helps. Best wishes.

  17. Hi Sarah – No, you would be perfectly fine using lemon oil with the castile soap. I do that myself with my wood polish. Oil does not have a pH, and therefore there is no acidity to interact with the soap.

    Hi Asia – I am so very sorry to hear about your discomfort. UTI’s are truly horrible. The only remedy is a round of antibiotics, and a doctor would need to do a culture to make sure that you take the right antibiotic to kill the bacteria. Cranberry juice only helps prevent UTI’s and may relieve the discomfort a bit, but will not get rid of them once they start. The combination of the soap and vinegar is not toxic, it’s just greasy. If you wash again with just the soap, you’ll be able to get rid of that. But definitely get yourself to a doctor to treat the UTI. They do not go away on their own and can go up into your kidneys.

    Thank you, Anna, for weighing in. I hadn’t seen her post last week.

    All the best,
    Lisa

  18. Hi! One more question, can you mix Dr Bronners and hydrogen peroxide? Thanks!

  19. I tried using castille soap diluted to wash my car today. Our driveway is made of pale red bricks, and after I was finished and moved my car I was left with a whitish discolouration to the bricks in all areas where the sudsy water ran down. Is the brick permanently damaged or is there something that can be used to rinse of the white build up? Is the sal suds a better option for car washing? I read a response that said vinegar can discolour some types or stone, but I did not use any vinegar, just peppermint castille soap highly diluted. Also, I once took a bath with tea tree oil castille and epson sAlts. It reacted a created that thick white foam like soap scum. It was a huge mess The thick film was tough to clean. Almost like getting candle wax off the entire tub! So this reaction is common with magnesium just like vinegar? The epson salts were top quality, from health supplement store. Thank you.

  20. Hi Omni – Dr. Bronner’s castile does not react with hydrogen peroxide. So, if you want to mix them, that would be OK.

    Hi Kerry – As soon as I read your first line, I knew what you were going to say. You have a white driveway. It is not permanently damaged. What has happened is that the castile soap reacts with minerals in hard water and on outdoor surfaces. It leaves behind a white precipitate of mineral residue. The same thing would happen with the minerals in Epsom salts. In time, this residue will go away. If you want to go out and scrub the surfaces with a stiff bristled brush, it would help. An acid like vinegar would help dissolve the residue as well, but it seems like a rather large application in this case, and vinegar can dissolve soft stones, but I don’t think such stones would be used in your driveway.

    The best option for car washing is Dr. Bronner’s Sal Suds Biodegradable Cleaner. It does not react with minerals at all, and leaves cars very shiny.

    Please let me know if I can be of further help.

    All the best,
    Lisa

  21. Thank you for the quick reply! I will add the sal suds to my cleaning products team! Phew! I’m glad the driveway is not ruined. Now that I have a better understanding of the castille soap, I will use it more wisely in the future! Its a great product. The more u know about how to use it, the better! Thank you!

  22. What about using this in the dishwasher? Should I put Dr Woods’s, which is what I have, in the detergent area and the vinegar water combination in the same place afterwards and run a rinse cycle?

  23. If you’ve already gone ahead and incorrectly mixed castile soap (we used the orange) and vinegar (and then diluted with water) and had the unfortunate “curdling” reaction… is there anything else that can be done? Or is that mixture now garbage? Can I use the new (albeit unfortunate) separated concoction for… anything?

    My partner “made dish soap” by mixing castile soap, vinegar, and water, and now I have a pump container full of separated oils (and a cranky feeling). I wasn’t sure if there was anything to do or if I should just dump the container and start over.

  24. Knowledge is power, Kerry!

    Hi Ruth – Castile soap does not work well in the dishwasher. It may get the dishes clean, but even with vinegar in the rinse compartment, your glasses will probably be cloudy at the end. We’re working on a good option here at Dr. B’s, but at the moment, we don’t have one.

    Hi LM – Yep, you saw that there’s nothing it’s good for. I hope you and your partner are on speaking terms! It’s a common mistake.

    All the best,
    Lisa

  25. Thank you for the information. I found this post after i tried to make a homemade fly natural repelent for horses. I needed soap to disolve the citronela essential oil ( I disolved in water some home made soap), then i added vinegar – resulting in a greasy mixture

  26. I don’t know of you addressed this in other comments but I was wondering if I could mix castile soap and dawn? I am trying to make dish washing liquid but I can’t get over the fact that is has little to no suds. I know that I doing need suds to get things clean but I really can’t get over it. Or do you have another product I can use to create suds?

  27. Is it ok to mix Dr.Bronners with water and tea tree oil to make a disinfecting household cleanser? I’ve been using it but want to know if it is recommended, because i read something in the comments about not mixing it with oil. Thanks!

  28. Hi Lisa,

    NO QUESTION

    I just recently became re-interested in going “all natural” with ALL my household products and so I’ve been stalking drbronners.com incessantly! Any who, I am preparing to make a purchase/splurge in the next couple of weeks and plan to buy 1 each of ALL the castille soaps. I LOVE the packaging as well as the variety and there’s just something about seeing those 8 bottles all lined side by side that makes me happy!!
    I’ve been scouring the internet of various blogs devoted to homemade, natural cleaning methods in addition to homemade, natural personal care items( ie toothpaste, oil pulling, facial cleansers, etc.) This has really been a fun and exciting journey!
    THANK YOU!

  29. I do understand the basic chemistry behind the no mixing vinegar and pure soap thing, but the recipe I use that includes both works amazingly well! I’ve never had a problem, and it can get the nastiest shower floor scum off with a little grit added from sprinkling some borax down on the scum first.

    Isn’t soap a salt not a base? The lye is the base, and the oils to make it are acids (fatty acids). Once the soap is made it should be more salt than base, otherwise it would be too harsh on the skin. Good soaps are right around neutral, maybe a tad alkaline (7-10 on the pH scale), while vinegar is around a 5 on the acidic side. Adding the two together shouldn’t really alter things over to one side or the other too much, and it shouldn’t separate the oils. Maybe if you have a lot more vinegar than you do the soap so that it truly becomes acidic again? I’m not a chemist, so maybe I’m off on that.

    I use this recipe and it works wonderfully to clean and is not oily. Perhaps it is the borax added that keeps it balanced? I use the lavender Dr. Bronner’s with and I love how the room smells after I’ve been cleaning with it! The ingredients all seem to tie together very nicely, including the vinegar. Perhaps it is because the vinegar is added to the water and borax first before the soap is added.

    http://www.livingasimplelife.com/natural-purpose-cleaner-diy/

  30. I use bar soap for shampoo, followed by a pure white vinegar rinse. Works great for me and is el cheapo!!

  31. Hi there. I am trying to make dish soap lately with the help of YouTube. I would like you to see if this is ok… 1 cup of water, 1 cup of liquid castile soap and 2 to 3 tablespoon of distilled vinegar. If I add water before vinegar to the castile soap, there will not be such reaction…does it mean it’s ok then?

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