Pure & Mild Castile Soap

Pure & Mild Castile Soap

Of all the products I’ve made myself, soap was always the DIY project that dare not speak its name. The ingredients were simple, the outcome was delightful, but there was that middle part with the horrible threat of flesh-eating burns and death that kept me relegated to scrubs and salad dressings.

But when I came across a recipe for a pure olive oil soap, it was so simple, I couldn’t resist. It seemed the perfect place to start.


  • 50 oz. (1.5L) olive oil
  • 6.3 oz. (178.6g) lye
  • 15 oz. (.5L) distilled water

This should yield about 30 two- to three-ounce bars. (Holy crap, right?) I’ve halved the original recipe to make it more manageable after I found myself working with over ten pounds of ingredients once I got going. This one is more… apartment-sized.


To get a sense for the soap-making process before you do anything — the steps, the tools, and how to be safe — I recommend The Crafty Gemini’s YouTube tutorial.

I started by heating the olive oil on the stove. I knew it would hold its heat while I made the dreaded lye water. Like most things in life, the lye water actually wasn’t that hard. Aside from the fumes smelling like instant death, the only unexpected moment of panic was measuring the lye, when a static charge on my measuring cups sent lye granules flying everywhere but in.  After I made the lye water outside, I poured it into a 5-gallon bucket with my olive oil and blended it for all it was worth until it was about the consistency of school cafeteria custard. (It looked about as appetizing, too.) This is another reason I halved the recipe, because 10 pounds of flesh-eating sludge can be surprisingly daunting in the moment.

Back inside, I’d lined shallow cardboard boxes and cut-out milk cartons to act as moulds. I slopped in my soap, and decided to add essential oils to a few now that I had smaller batches. The rule for essential oils is about a half-ounce per pound of soap. So I grabbed one mould, weighed it, measured some essential oils — I went for the peppermint and rosemary — and just poured it on top and mixed it all in. Then I put the soap moulds off to the side and covered them with a garbage bag, then blankets to insulate them overnight. (Oh, all right, it was dirty sheets and towels.)

Simple Castile Soap - thecrunchyurbanite.com

Score your blocks every one to two inches before you start cutting for uniformly-sized bars.

I didn’t understand that last step until the next day when I took the blocks of soap out for cutting. The soap that’d been insulated was rock hard, while the dirty mixing bucket I’d left outside in the cold had soap, too, but kind of smooshy to the touch. Heat is clearly a commodity. I cut 1-inch-thick bars that (depending on the moulds) came out to about 2 or 3 ounces apiece. (And, yes, I was squealing with delight with every bar.) Then I arranged them to dry and left them alone for about 6 weeks to cure into nice, hard bars.

The clean-up. For some reason, everyone always forgets this part when they talk about soap-making. So here’s the deal: you can clean up the day of — as some people certainly do — but any lye that hasn’t found a fatty acid molecule in the oils yet will happily go for you, or various things in your kitchen like aluminum. Plus, any oils that haven’t been saponified by the lye can stick to your pipes and potentially clog your drain. I say your best bet is get as much off your tools as possible, then let everything sit overnight. The next day, anything questionable will be plain old, bona fide soap!


I don’t know about other cities, but in New York, a bar of natural soap like Dr. Bronner’s is almost $5. But if I divide the number of bars I made in this recipe from the cost of all my ingredients — not counting the scale and thermometer and all the upfront stuff — a bar of quality, natural soap only costs me 80¢ a pop. Eighty cents! Not too shabby, huh?


I used an old shower caddy as the perfect drying rack to hang compactly out of the way.

A lot of people are probably thinking, “But, Crunchy Urbanite, doesn’t bar soap dry your skin?” Nope. Conventional bar soaps do dry your skin, but that’s because conventional bar soaps aren’t soap anymore. They’re detergents. Castile soaps like this one create glycerin in the saponifying process, which your skin loves, and which chemical companies remove from conventional bar soap to sell back to you in more high-end products like moisturizers and lotions.

“But, Crunchy Urbanite,” you’re saying. “You’re so gung-ho about organics; how come you didn’t say to use organic olive oil?” (Or at least, that’s what I said to myself.) The truth is, when I saw how much it would cost me to buy large quantities of organic olive oil, I did a little sleuthing. Olive oil is one of those crops with next to no toxicity difference between conventional and organic. Personally, I’ll still buy organic for cooking, but for something like soap, I went conventional.


Smelling my soaps curing for six weeks was incredible. But using them was even better. Pure olive oil soap doesn’t lather much — a frothy lather typically comes from added detergents for show, anyway — but, wow! What a great clean.

I think I’m hooked.

Make your own natural soap - thecrunchyurbanite.com



51 responses to “Pure & Mild Castile Soap

  1. Can u use this for any thing u’d use regular castille soap for like to make dish soap or use for shampoo?

    • That’s what I do. The last batch of soap I made, I used the scraps to scrub a cast-iron pan I’d cooked breakfast in the day before. Worked like a charm. And actually, I prefer shavings from my soap mixed with aloe juice in lieu of Bronner’s for my homemade shampoo. I find it’s gentler. (Blog post and recipe coming soon!)

    • Ha! My pleasure. Yeah, like with anything in life, it’s never really as bad as you think it’s gonna be. My problem is now I can’t stop. 😉 If you wind up making soap and think to, drop me a note again and tell me how it turned out!

  2. I’m a soap rafter for nearly 20 years. Castile traditionally has a fine, rich lather rather than fluffy, bubbly lather. Sugar dissolved in the lye solution also adds richness to the lather. Salt dissolved in the lye solution adds hardness to the bar. Typically, because olive oil is so high in fatty acids, Castile Soap should be cured for at least 6 months for a truly mild, hard, long lasting soap. The idea is to allow as much water moisture as possible to evaporate. Let some of yours cure for that long and you’ll see the difference! Also, try Pomace Olive oil next time for Castile… Big difference! It has the highest amount of unsaponifiables so it makes for a very creamy, moisturizing soap.

    • Melissa, yes! Thanks for this. You’re right: I have definitely found that the longer my bars have to cure, the better they are. The only downside I’ve found to time are the orange spots some of my soap gets when it’s exposed to the air too long. The curing time I’ve got is the bare-bones minimum to keep the bars from turning to mush in the shower… 😉 Right now, all my unused babies are wrapped in tissue paper and stashed away in my dresser with my clean laundry. They seem to keep better — and the laundry smells GREAT. Very curious to try your salt/sugar suggestions, thank you!

  3. Thank you for this wonderful post! I especially liked the clean-up process. The lye part of soap making doesn’t scare me. My worst fear when it comes to making soap has always been the clean-up. Now I know I can do it. I just need to find the time and the space in my tiny apartment. Can this recipe be halved again? For an even smaller batch?

    • Yes! Soap-making is just pure chemistry, so as long as the proportions are the same, halving it a second time, or a third time, or a fourth time, should be fine. Also, if you have an iPhone, check out the free app “Soap Calc” and tinker away!

  4. i would love to do this but i live in a very small apartment on the second floor and its getting really cold outside, would i be able to do this safely now or should i wait till warmer outside or see if a friend wants to try this at her house cuz she has more room?

    • Truthfully, the first time I did this, it was freezing out. (Early April in NY.) It was actually a plus, because it helped cool the oil and lye water to mixing temps faster than when I’ve done it in warmer weather. But for moral support and more space to play in — especially for a maiden voyage — waiting might not be a bad option, either.

  5. Ok, my question… Is lye bad for you? I am thinking of a lye bath my mother in law uses to pull the skins off her peaches before canning them (I don’t use it). It is like an acid. Is this something different?

    • Lye’s not good or bad. It just is. It’s naturally occurring, but if it’s in too high of concentrations, it can do a lot of damage. (It is caustic, after all.) You mother-in-law is probably using an extremely diluted version for her peaches. (Especially since she’ll be eating them later.) Think of it like bleach: a dollop in a pool is all right to chlorinate, but you wouldn’t swim in it full-strength. To make soap, you need lye, though; no way around it. But don’t worry, it’s nothing to be afraid of if you’re mindful of what you’re doing.

    • I actually was surprised by how nicely this lathered, because I was expecting it not to. You’re right, though: a little coconut would help froth things up nicely — but I wanted to keep this pure Castile. I do have some coconut soap recipes I want to tinker with for shampoo bars, and will post that as soon as they’re ready.

  6. Haha!!! I LOVED this post! I just started making my own soaps this year, and I totally feel you on the lye experience. I’m still a huge baby about it, and it scares the bejeesus out of me every time I mix it. Every. Time. I now have a “lye outfit” my husband laughs at. Gas mask, rubber gloves to my elbows, and a hoodie. I can’t help by say, “Are you my mummy” every time I put it on (if you watch Doctor Who you’ll get it).
    Thank you for the awesome post. I’m now a follower.

    • Hahaha, that made my day. I totally know what you mean. I’ll watch soap-making tutorials on YouTube with little old ladies mixing lye in sleeveless blouses and feel like a big baby. I’m getting more relaxed, but there’s always an open jug of vinegar within arm’s reach… juuuust in case. 🙂

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  9. I love your simple recipe. I see a lot of people freaking out about the lye in soap… it won’t jump out of the bowl at you people!!! Anyway, I made my soap last night, it still has another 8 hours to sit. It smells nice and mild… can’t wait to turn it out of the mold. I did take the last cup of soap and added a bit of oatmeal and put it in a pretty mold!
    (Note: When I added the lye to the water I stood back and didn’t smell a thing through the whole process, except the smell of “cooking” oil.)

    • Aw, thanks. I think the biggest obstacle — like most things in life — is always just getting started. I remember once the winds shifted while I was mixing lye water and I caught a whiff. Ooof. Makes horseradish seem like chamomile! But congrats and welcome to the club.

  10. I made a batch of this on Thursday. It had it’s 24 hour sponification, then a day it sat on the rack overnight. I used some crumbs and an end pressed into a ball today when I took my shower. It lathered really nice, it rinsed off well and made my skin feel soft. I am happy with this recipe and will probably use it a lot!

    Thank you for having this recipe on your blog!

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  13. In case you don’t know, different oils in a soap recipe have different benefits. Some oils are very mild like olive oil, and some can add other benefits like coconut oil for a good lather, etc. I am waiting for my supplies to come in the mail, mainly lye, I can’t wait to get started!

    • Have fun. Yeah, soap-making is definitely a slippery slope… if you’ll pardon the pun. This recipe was intentionally olive oil only, but I’m also a big fan of adding coconut oil because it does lather really nicely and coconut oil is also drying… which, let’s face it, is great for those of us whose skin gets oily in the summer.

      (Tiny rant: lots of soap recipes love to use palm oil, too, but avoid it, if you can. Palm crops are kind of the single-largest ecological threat in Southeast Asia right now — they’re burning down all the rain forests to make new farms… and palm oil is pretty much *the* reason there will be no Orangutans in 5 more years. So, you know… stick with olive and coconut, k? Aaaaand rant over.)

  14. I’m super excited to get some soap making done. However, I have a question – I tried my first round tonight and it just never made it to the trace. (Granted, I had to use a real mixer, no stick one available yet and I was overly excited). Is it just the mixer or is there some other way I could have messed it up to make it not trace? Id love help as I really do want to make it well. 🙂 thanks!

    • Hey, I’ve never had a batch seize on me — knock on oil — but from what I’ve read, I’m going to go out on a limb and say it’s because of two factors that worked together to sabotage your maiden voyage: size and temp. You made too small a batch in too conducive a metal bowl and lost heat too fast before it had enough time to come to a complete trace. Not that a mixer is a HUGE difference from a stick blender, but one mixes and one definitely blends. I prefer the speed and thoroughness of the latter. Next go around, try a food-safe plastic bucket (remember: never anything aluminum, or really any metal that isn’t 100% stainless steel), and try a bigger batch. Good luck, and drop me a note in the future if you remember to let me know how it went.

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  16. somehow I have stumbled upon your website and I love it! I tend to find mainly women talking about homemade and natural things which is great as I am a woman however I have 5 brothers and mainly men in our family. It is very nice to me a mans perspective and also recipes! can’t want to dig deeper into your info. thank you very much from a “half homesteader” ha ha

  17. What temp range do you blend your lye and oil? The recipe didn’t metion one. I’ve been making soap for about ten years and I haven’t tried a pure castile recipe. I’m looking to use it for laundry soap.

  18. This post is amazing!! I’m now officially your fan 😀 I want to make this soap so bad, but I have a question: about those orange spots (DOS) that appeared in your soap, how often does it happen to you? I mean, since you started doing soap, is that something that only happened once or… Because that is the only thing that keeps me from doing this

    • Thanks. 🙂 Those orange spots really come about from air and age. Keep your soap wrapped in paper, stored in a linen closet or drawer someplace dry, and use it all up within a reasonable amount of time – and you shouldn’t have to worry about it. It’s the soap equivalent of an apple slice turning brown. Seriously not a big deal. (And if it does happen, hey, who cares? Those spots will be gone after your bar’s first use, anyway.) Happy warshin’.

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    • Hi, Brenda. I’m sure Amazon or any major online retailer would carry lye. I buy mine from Lowe’s. Look for it under “home improvement,” since it’s commonly used as a drain cleaner. Just make sure you’re buying 100% lye (AKA “caustic soda) and not a blend of things. Happy soapmaking!

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  22. Hey there. Most of the time I have seen a bar soap made with sodium hydroxide. I got potassium hydroxide in the mail as I would rather have liquid soap and in my research it showed to use this instead. Do you know if this ingredient change might work for the same process without the hardening step, or should I follow your steps with the sodium hydroxide and mix with hot water later to make liquid (which I have done with bar castile before to save money).

    • Hi. You know, I don’t actually know. There’s a process of making lye from wood ash that I’ve been fantasizing about and I think I remember reading that the result is potassium hydroxide, as opposed to sodium hydroxide — but was still indicated for making bar soap, frontier-style. So I imagine regardless, you’re still going to take the extra step to yield liquid soap. But again, that’s just my educated guess.

  23. Potassium Hydroxide is used to make liquid soaps. You cook it down until it looks like very thick vaseline, this can take around 6 hours in a crockpot.

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  26. Hello Mr.Crunchy..lol I have been dabbling in the soap arena for minute now and I’m loving it. I know I read some wurs(yes that’s a unfamiliar word I jus love to use) that cp(cold processed) can be made into hp(hot processed)soap. I am anxious and have little to NO patience so waiting for weeks to use my creation is nawt gonna happen…So I prefer using my handy dandy $2 fleamarket crock pot to whip up my soaps. Sorry I babble..lol…SOOO my qwerstin (another one of my wurds) is can I use this as a hp recipe and half or divide the amount to include Coconut oil for lather? Yes I know this is a Castile soap recipe but I’m a latha kinda chic

    • Howdy, Mz. Puddle. Yes, you can totally turn cold-process soap into hot-process. And you can cut this recipe in half, too. Or quarters. Just be sure to double-check your ratios in a soap calc app to be safe.

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