This article will show you how to make your own castile bar soap. If you enjoy using natural soaps, this will show you how save money making it yourself for about $1 US per bar.
First something that needs to be said about soap. There is NO WAY to make bar soap without using lye. It is a physical impossibility. The basic reaction that is needed to make soap, called ‘saponification’, cannot happen without some form of lye reacting with some form of oil. Lye is actually a general term for a very strong alkali (the opposite of acid on the PH spectrum). There are generally two alkali’s that are used in soap making, sodium hydroxide and potassium hydroxide. Both are considered lye, but the potassium hydroxide is not strong enough to make a solid soap. It is only used for making the liquid soaps in today’s world.
Soap manufacturers today do everything they possibly can to hide the fact that they use lye in their soap. They have made up lots of names to hide it. Dr. Bronners soap, which many naturalists are in love with as a natural soap, uses lye. They hide the fact in their ingredients list by saying that they use “saponified oils”, which is the process of mixing lye with oil. The public is afraid of the word lye, but they have no idea that it is used in every bar soap ever made. Soap simply cannot be made without it.
The important thing in any soap recipe is using the proper proportion of lye and oil to form a PH neutral soap when completed. In times of old, soap makers were not using a pure form of lye in their recipes. The PH of the lye was not consistent, so their end product could end up being very alkaline, and burn the skin. The story of “lye soap” burning the skin has been passed through the generations, creating public fear of the word. When properly used, lye is our friend. Lye (sodium hydroxide in this case), when mixed in the proper proportions with hydrochloric acid, produces a strong chemical reaction resulting in table salt, something we have been eating for hundreds of years.
The recipe below uses the proper proportions of oil and lye to create a PH balanced soap that will be very mild to the skin.
Here are a few tools you will need:
- A digital scale capable of 5 lbs measurement.
- 2 glass bulb thermometers that can measure up to 200° Fahrenheit.
- A stick blender.
- A high temperature plastic jar (to mix the sodium hydroxide and water).
- A long-handled plastic mixing spoon.
- A ladle.
- Two large plastic bowls.
- Soap molds.
Here is the recipe:
- All measurements are in weight – not fluid ounces.
- All bars are assumed to be 4oz.
| Full Batch | Half Batch | Quarter Batch |
| Makes 28 bars | Makes 14 bars | Makes 7 bars |
| 24oz Cold Distilled Water | 12oz Cold Distilled Water | 6oz Cold Distilled Water |
| 12oz Sodium Hydroxide (lye) | 6oz Sodium Hydroxide (lye) | 3oz Sodium Hydroxide (lye) |
| 74oz Olive Oil | 37oz Olive Oil | 18.5oz Olive Oil |
| 14oz Coconut Oil | 7oz Coconut Oil | 3.5oz Coconut |
Caution: Whenever working with Sodium Hydroxide it is recommended as a safety precaution that you use rubber gloves, goggles, and any other protective gear that you may want to use in order to protect your skin or clothing from accidental splashes of the liquid.
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Add lye to water in a high temperature plastic container outside of house. Do not breathe fumes. Always add Lye to water (not reverse). Caution: Temperature of mixture will rise to approximately 195ºF. Stir mixture with plastic spoon.
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Mix oils and microwave to 110ºF.
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Allow lye to cool (place in bowl of cold water to speed up cooling).
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When both solutions are at 110ºF, add lye solution to the oil mixture. Blend with stick blender until the mixture reaches “trace” where you can see a film on top of the soap that traces the line of the stick blender. Ladle into molds.
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Handle bars with care for next two days. PH will be high and can burn the skin for the first 48 hrs. The PH will settle to neutral after this.
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Place molds in freezer for 30 minutes to help separate the soap from the molds.
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Allow 6-8 weeks to air dry before use.
Distilled water is used to guarantee that the PH of the soap will be neutral when complete, and that no impurities are in the water that could affect the saponification process. Distilled water can be purchased at any shopping center in a one gallon container.
Lye (Sodium Hydroxide) can be purchased locally at any Lowes home center. A two-pound container of Roebic Crystal Drain Cleaner is available for just over $12. Make sure you buy the one that says 100% lye. Or, you can purchase it in bulk HERE. Two pounds are plenty to last more than two full batches.
Please note that sodium hydroxide is considered a hazardous substance, and shipping prices increase significantly because of this. It is also used in manufacturing certain illegal drugs, and some states may regulate the sale of lye for this reason.
Soap molds can be purchased HERE or at many other internet soap supply retailer.
How to make your own Castile Soap like Dr. Bronners from Frugalberry.com on Vimeo.
I now have an article posted on how to use this bar soap to make your own liquid castile soap. Check it out HERE.
Can you add colors and essential oils to fancy the soap up?
You absolutely can Mandy. I didn’t include that in this post, but I may do that later. You add your essential oils right before you blend the mixture.
Thanks. I think I’m going to try this.
Stay tuned. My next post will be on how to make liquid soap (like Dr. Bronners). It’s the exact same stuff for a fraction of the cost.
Hi Karl – was interested in finding out when you are going to provide information on how to make soap like Dr Bonner’s. Can you let us know if you have done this yet and where we can find the information.
Thanks ! Susan
Susan,
Here’s the link: http://frugalberry.com/make-your-own-liquid-castile-soap/
Hi Karl – thanks so much for getting back to me. Yes I did see your method of making the liquid soap by using a bar of the castille soap. What I am interested in is if you have the recipe for just making liquid soap from scratch without using a bar. It must be something to do with the measurement of materials.
Really enjoyed your webcam instructions on the bar making…very clear.
Looking forward to hearing from you on this.
Susan
Susan,
Sorry, I have never made liquid soap directly. Though it can certainly be done, and is the standard method for making liquid soap, it is a different process than making bar soap. Liquid soap typically uses sodium hydroxide (a more mild lye) instead of potassium hydroxide, which changes the recipe significantly.
Maybe one day I will attempt making liquid soap directly, but this is not on my current agenda.
Karl
Do you add the essential oils right before you blend to trace? I’m about to try and make soap for the first time and want to make sure I get it right. Also, is there a certain amount of the essential oil I should use?
Tamisha,
Yes, exactly….. just before blending. I use 10-15 drops of essential oil (depending on the oil and the potency).
Hope it works out well for you!
Karl
Hi can you post brand of coconut oil and essential drops you use in this video??? Thank you!
Amanda,
I’m not very brand loyal. I switch between coconut oils depending on price. Sorry.
Karl
Wonderful website you have here but I was wanting to know if you knew of any discussion boards that cover the same topics talked about here? I’d really like to be a part of community where I can get feedback from other knowledgeable people that share the same interest. If you have any suggestions, please let me know. Kudos!
Sorry. I don’t know of any. Let me know if you find one!
I recently went to lowes to get the lye and was told that they no longer carried the roebic crystals..the closest they had was Enforcer Crystal Heat..can I use this?
Ann,
What state do you live in? Here in Pennsylvania they stopped carrying it for about a year and then started again about 6 months ago. What you may need to do is order it from Lowes on-line for in store pickup. Buying lye locally has been a big problem for soap makers over the years. You used to be able to get something called Red Devil lye, but that was taken off of the shelves about five years ago, and I haven’t seen it since. There seems to be a big issue with lye being used in the illegal drug processing operation.
To answer your question about Crystal Heat. NO it is not suitable for making soap. You need to find something that is 100 percent sodium hydroxide. To my knowledge the Roebic is the only one available locally. Try the on-line order with in-store pickup at lowes. If that doesn’t work, you may need to buy it from Essential Depot and pay for the shipping.
Ok I’ll try the online ordering..thanks..
Keep us updated Ann. What state are you from?
I’m from ky. Turns out they stopped stocking it so I could not order it for online pickup But I can get it from a Lowes farther away so that’s what I am going to do. It is about 50 miles away..
Wow! Sorry you need to travel so far! I think this would be much more expensive when you figure time and gas into the equation than just ordering it from Essential Depot.
Ann I know this reply is rather late, as I see the date of your post on Frugalberry.com was back in Feb.. . .
I usually get my Lye from Ace Hardware. If you dont have one locally, you can order online.
Their brand is Rooto, or something like that, and the 1 lb jar says Drain Cleaner. . . Check the label- it will say 100% Lye or Sodium Hydroxide.
The other place to get lye- online is at EssentialDepot.com They have good prices and deliver quickly. If you sign up for their newsletter, you get notice of sales and specials too. . . Hope this helps!
http://www.brambleberry.com/ sells Red Devil for 10.00 for 2 pounds total cost with shipping is around 18.00
I actual work 5 miles from the store so its not that bad.
Let me know how it goes….. and if you are on facebook, please share this page with your friends (at the top). I can use as much exposure as possible. Thanks!
I will..I’m really looking forward to making the liquid.. I’m assuming u use the potassium hydroxide for that.. Where do u buy it?
Stay tuned. I should have the liquid soap article posted shortly.
Great!!!
Hi!
When does the “dangerous” part is over with the sodium hydroxide? once it is melted into the water or when it is joined to the oils?
Once it is mixed with the water and the water is clear you are past the most dangerous part. You can still burn yourself if you touch the liquid before mixing it with the oil, but once it is mixed with the oil it becomes very mild. 24 hours later it should be ph neutral.
Hi!
Thanks for the quick answer! Great videos too!
I try making the soap but there are several problems:
1. The soap did not harden enough even after 2 days.
2. The color of the soap is not homogeneous, it has darker stripes in it.
What can be the explanations for this? What did I do wrong?
Orly,
It’s hard to respond with this little information. It could have had to do with the temperature you had both the lye and the oils prior to mixing, or it’s possible you didn’t get it to trace prior to pouring.
You say the soap didn’t harden enough even after two days. At this stage, you may still be able to put your finger print into the soap, but if it’s still liquid there is definitely a problem. Try letting it sit for a few more days to see if it sets up then.
Are you sure you used 100% sodium hydroxide?
I would like to make this into liquid shop shortly after releasing it from the mold. Is this okay or should I wait until it has cured for 2 months Thanks
I would wait at least 48 hours from trace. At that point the bar should be ph neutral. If it’s not, it could eat through the bag before it has turned to liquid.
Eat through the bag?? What bag? LOL
I always use a stainless steel pot or
plastic bucket to make my liquid soap!
Yes Danielle, you can make liquid soap from the bar soap just after it comes out of the mold, in 24 to 48 hrs. . . Best to use gloves when you shred it up though, as Karl says, it isnt quite PH ready, Also, with this being a Castile soap, it will be somewhat soft. . . which make it harder or even easier to shred it, depending on how you do it (Salad shooters are great for this!) Fresh shredded soap, hot water, a little washing soda, and you have a liquid soap!
Lady Angel,
I’m guessing you haven’t read my post on liquid soap. Give it a try! http://frugalberry.com/make-your-own-liquid-castile-soap/
Karl
I see you are using a dry weight scale to measure your liquid. It looks like your 4 cup quart jar is has quite a bit more than the one cup of water your recipe calls for. That seems to work as I was viewing your video everything went together ok. I do want to try this as I make my own laundry detergent and that work very well.
Mslilypad,
Please look at the recipe on this page. If you follow the recipe you can’t go wrong.
Karl
Mslilypad, The recipe is measured by weight Not cups! mslilypad
Hi,
I have a book with soap recipes but they all start with a “soap base” instead of making it from scratch like this one. I was wondering if I could use this recipe to make bars that I can hand grate and melt later to use as the “soap base” for the recipes in the book that have the add-ons (like honey, oatmeal, flower buds, essential oils, etc) Your help is appreciated!
Mya,
Thanks for posting! I’m glad you like this article. I have tried melting this soap down as a base, but it doesn’t work. For some reason this soap simply will not melt. I don’t know why. However, you certainly CAN add what ever you want to the recipe before it hardens, such as flower buds, essential oils, coloring, etc. I don’t know why anyone would want to put Honey in a soap, but I guess you could add that also before it hardens. There is certainly room for experimentation.
Enjoy!
Karl
Hi Karl, thank you very much for this informative video! I am just wondering how long after you make the soap it takes to solidify. Mine has been out for 12 hours and has not solidified past the consistency of thick pudding. Thank you so much!
Brittany,
I’m guessing, by the time you read this, that you have already found your soap has hardened. From my experience it takes 24-48 hours for the soap to harden. It all depends on how closely you measured your ingredients and how well the soap came to trace when you mixed it. Temperature at mixing can also have a big impact. The good news is that you are almost certain to have the soap harden, even if it takes a few days longer than anticipated.
I hope this helps!
Karl
Thanks so much for your great video and recipes! For the first time I feel confident I can make my own soap. If you use all olive oil instead of coconut/olive oil mixture will it cut down on the lather? I would like to use all olive oil but I want it to lather too. Thanks!
Shelly,
I’m glad you found this helpful!
I’m not sure about lather when switching to all olive oil. I suspect it could dry out your skin. However when you change the type of oils used, or the quantities of different types of oil used it effects the amount of lye needed in the recipe to end up with a PH neutral soap when completed. If you do choose to try it, please use a lye calculator to determine the proper amount of lye for your new recipe.
Here is a lye calculator you can use. There are many of them on the web: http://www.thesage.com/calcs/lyecalc2.php
Karl
Hi great recipe but I wanted to know if this recipe can be used as just an oil if glycerine was added! Thanks
Eleni,
I have never tried. Check it out and let me know your results!
Karl
Thanks so much for posting this! This was my first try at making soap and the directions and video were very easy to follow. I made it last weekend and have a few questions about the result. When I poured it into my molds it looked like there were tiny bubbles all over the top. Also, I have now removed them from the molds and it has been sitting for about a week. It appears that the bottom of all the soap is going to be very crumbly because of the bubbles I saw. Also, with the last mold I poured I can see what looks like streaks of oil (darker yellowish streaks). That only happened with my last bar though. Do you know what may have caused this? My temperature may have been a little cooler than 110, maybe 107 because I accidently cooled the lye mixture too much and then had to set it in hot water to warm it back up All of it does look like soap though so I think I’m at least on the right track. Thanks again!
Stephanie,
Did you use a stick blender with interchangeable blades? The bubbles could have been used by the blade that you have on the stick blender. That’s just a guess. I’ve never seen the bubbles you are referring to. It also sounds like the bottom of your bowl didn’t get mixed well. The temperatures you have listed should not have a drastic effect on the soap.
I hope this helps.
Karl
Thanks Karl! I don’t believe the blades are interchangeable. It is just a two sided blade and only has two speed settings. The blade or speed may have been an issue. Is the soap still safe to use even if it didn’t mix completely? I want to use it for laundry detergent so I’ll have to follow your liquid soap directions, but didn’t know if the lack of mixing would cause a problem with the effectiveness of the soap. Thanks again!
Stephanie,
If the soap hardened, you should be OK. One way you can check it to be sure is to place a piece of soap in distilled water and let it dissolve overnight. Then take some PH test paper and check the alkalinity of the soap water. It should be PH neutral (7.0). You can get PH test strips where ever pool supp.ies are sold (Walmart has them in season). Again, you should be OK, so I wouldn’t sweat it.
Blessings,
Karl
Will def do that! Thank you so much!
Also another quick question, if I am going to make the liquid Castile soap do I still need to let the soap sit for 4 to 6 weeks before I make the liquid soap?
Stephanie,
That’s a common question. No, you only need to let it sit for 48 hours until the soap PH neutralizes.
Good luck!
Karl
Ok so I bought aquarium ph strips and tested the liquid Castile after 5 days and it looks like the ph is about 8.5 so I guess I must have done something wrong. I wasn’t too sure what trace was so maybe I didn’t mix it enough. I’m assuming it’s not safe to use at that ph?
Stephanie,
Yeah, unfortunately I think it needs to be tossed. You used distilled water I assume? If not, you may want to test the PH of your tap water just to see. You can also test your test strips by putting it in some distilled water. Distilled water should be reading 7 on the nose.
Karl
Yes I did use distilled water and just tested that to be sure and it was at 7. I’m not giving up though and hopefully things will go good the second time around. Thanks again for the advice!
We made liquid laundry soap for the first time the other night, it cost $2.50 to make 5 gal. of concentrate(that equals about 12 gal. of store bought at $7 a gal). We’re going to make this soap tonight and I can’t wait to see how it turns out! Thanks for making the instructions so easy to understand.
Glad to help! Let us know how it works out!
Karl
We mixed the soap by hand for 1 hour, got smart and put the plastic spoon in my drill for 30 minutes until I thought we reached trace. The soap finally solidified enough to cut today. The top was soft and the bottom harder, very crumbly. Research indicated the soap got too cool while mixing by hand. My wife tried some of the soap as a test (we’re going to let it dry more) and while soft, it worked very well! I am pleased with the results and offer this suggestion; USE A POWER MIXER FROM THE START! Unless you have your soap over a heat source, hand mixing takes to long. I will use a paint mixer in my drill for our double batches in the 12X36 trough mold.
John,
Thanks for the feedback. It certainly sounds like something isn’t right with your batch. Was everything weighed before you started? Were the temperatures correct when you mixed them? Did you use 100% Sodium Hydroxide? I’m curious to know what may have gone wrong.
Thanks,
Karl
Everything was weighed on a digital scale, temperature was perfect and we used 100% lye (Red Devil). I’m thinking the problem was the hand mixing taking so long that the mixture cooled. The soap is getting harder every day, but it appears to be “two toned”. It does work though! No harshness and it cleans well. The next time I’ll use a power mixer from the start.
Hi Karl,
Bravo!!! I made the soap bars which turned out great!! 48 hours after I used one bar to make liquid castile and that turned out brilliant as well! On my way to use liquid to make other products such as dish soap, shampoo and body wash!
Thanks much!
Dana,
GREAT! Thanks for letting us know!
Karl
Hi!
I have tons of issues finding soap that I can use with all of my skin allergies and this could help me out without spending a ton of money. However, I’m allergic to coconut oil, is there another alternative that will provide the same/similar results?
Thanks
Andrea,
You can make this soap with 100% olive oil but you would need to change the amount of lye used. Use the recipe I have listed, substituting the olive oil for the coconut oil and adjust the amount of lye based on a lye calculator like the one here: http://www.thesage.com/calcs/lyecalc2.php
I hope this helps!
Karl
When making the bar castile soap do you just use regular olive oil that you can purchase at the grocery store?
Sheri,
Yes, you can use regular olive oil. The Extra virgin will make the soap smell of olive oil, so if you don’t care, I would recommend the cheap stuff to keep it smelling better.
Karl
Thank you very much and will let you know how my batch comes out next week. Merry Christmas from Central Texas!
Oh my gosh! I’m sooo excited over this recipe! My daughter has VERY sensitive skin, and I have to use all natural products throughout our house. This can get VERY expensive, so I was soo excited when I found this <3 Thank you thank you!
Great! Glad I could help! Tell us how it goes!
Can I replace the sodium hydroxide with potassium hydroxide? Would the quantity for each ingredient change? Apart from the recommended safety precautions will there be additional precautions to take due to the replacement of sodium hydroxide with potassium hydroxide? Thanks in advance
Loraine,
NO! You cannot simply replace one type of lye for another. The recipes are VERY specific for the type of soap you want to make. If you want to make liquid soap with potassium hydroxide you will need to find a recipe for that somewhere else. My method shows people how to make liquid from bar soap.
I hope this helps.
Karl
Soap 101 has a beautiful liquid Castile soap tutorial and recipe. Look for it online. Otherwise, thesage.com has a link to it. It uses Potassium Hydroxide and olive oil and glycerine. It’s the easiest recipe I’ve seen, and I’ve been studying a book about liquid soap. Mine turned out to be a beautiful clear amber color. It’s sequestering right now. I hope this is helpful! Peggy
Thanks Peggy! I’ll check it out sometime!
Karl
Hi there. I’ve noticed that everyone uses a plastic stick blender. My stick blender is metal (I’m guessing stainless steel). Can I use that or will it react in some bad way with the lye and oils?
Lexie,
I don’t see any reason why you couldn’t use it, though the lye may take it’s toll on it’s outside appearance. If that’s an issue, you may want to consider buying a cheap plastic one. Keep in mind that even the plastic ones have stainless steel blades.
Blessings,
Karl
Hi Karl,
Loved the updated video. I am curious about your stick blender. In your mayo video you say that it’s the same stick blender that you use in soap making but you clean it real well. How do you clean it after soap making? Do you use copious amounts of water, soap and water, vinegar?
Thanks!
Gabe
Gabe,
Good question. Yes, you guessed it. I use lots of soap and water to start, turning the blender on in the soapy water. Then I wipe it down with vinegar. This said, it is still much better to have separate items for soap / food making, but I’m too much of a cheapskate for that.
Blessings,
Karl
I don’t have a scale. What do these measurements convert to in ounces or cups?
Stefania,
If you are going to make soap you need a scale. Don’t try it without. You will end up with a soap that will burn your skin if you do.
Karl
Karl..I have an odd shaped soap mold that was made for me. I am a new soaper and I don’t know how to find a recipe to fit the mold, can you please help me out? The measurements are 15 in. long, 3 1/4 in. wide 2 3/4 in. high. The oils I would like to use are olive, coconut, palm and castor. Thank you so very much….jean
jean,
I would take a watertight bag, place it in the mold, and fill it with water until it reaches the top of the mold. Then I would weigh the water in the bag. This will give you the total weight of your needed liquids (approximate). Now you can make your own recipe based on the oils that you want. I would use about 2/3 olive oil, with the remaining third split between the palm and caster oils. Now do a simple web search for a lye calculator. Plug your oil numbers into the calculator and it will tell you how much lye (sodium hydroxide + water) you will need to make soap with these oils.
I hope this is helpful!
Karl
Thanks for taking the time to post the great video on making Castile soap! Also, I would like to know what brand, and where you purchase your thermometers and soap molds. Thank you!
Betty,
Thermometers I ordered from Amazon.com
Soap Molds I ordered from http://www.candlesandsupplies.net/
Hope this helps.
Karl