Lemon yogurt soap for fresh morning!
It’s really just a variation on the basic recipe, but my recipe testers liked it so much, I decided to feature it. During the testing, I kept getting emails: “Soap 20 was great” “I like everything about this one!”, “What in the world is in Soap 20? It’s best of all!”. No one guessed it didn’t have any luxury ingredients in it.
After such a description, it is evident I had to try it!
Contents
About yogurt soap
Yes, yogurt is not a luxury ingredient, but in the process of saponification, part of it changes to a chemical with perfect moisturizing characteristics: sodium lactate, as I will explain below.
This is the book on milk soapmaking from Anne L. Watson. It has a plenty of nice milk soap recipes (like the one that inspired this one) and explain nicely in detail the theory. |
This yogurt soap recipe is very simple and without palm oil, and therefore ecological!
I have made some changes to it:
- I added citrus essential oils, because I love lemon yogurt 🙂
- However, citrus oils are more volatile and less stable in alkali conditions, so I added also a bit of rice bran flour as a scent fixative (any other flour or starch can be used).
As this was my first time making yogurt soap, I also examined the effect of different temperatures on soap curing.
Usually, soap containing milk – and therefore yogurt soap -is refrigerated, because:
- it can get quite hot as milk sugars speed the reaction and we want to avoid a soap volcano
- the warmer the soap, the darker the color of the final soap
To avoid this, lye solution temperature is kept as low as possible by freezing milk/yogurt in advance and dissolving lye in it while constantly cooling the lye jar.
Then, after pouring, soap is put in the fridge.
My question was – is this necessary, and how does this affect the color?
What happens with yogurt in soap?
Apart of coagulation and hydrolysis of milk proteins,
lactic acid (one of the most prominent compounds of yogurt) reacts withsodium hydroxide, resulting in sodium lactate.
Sodium lactate is a safe food additive used for example as a taste enhancer, but what is of interest for us:
- it is a very effective moisturizer [1-3], because it is a part of “Natural moisturizing factor – NMF ” a set of compounds in our skin that have moisturizing role
- it is said that it has similar effect on skin as AHAcids, [I search for the scientific sources supporting this information]
- is used successfully for acne treatment [4]
- soapmakers love it, for at least five more reasons:
- it helps to create hard soap bar that is easy to unmold – I do confirm, but the saponification reaction must finish first (does not work for soap left in fridge or freezer, see below)
- in hot process it helps to keep the soap smoother and more easily swirlable (I didn’t try, so cannot confirm)
- it should help to conserve soap (not sure what was meant by this, EDIT 11 June 2013: N.B. in the comments below says it is to make it last longer – it does not use so quickly)
- stabilize the foam and makes it creamier – It does!!!! (EDIT 11 June 2013: Later I thought it might be thanks to sugars in 11the yogurt, too…)
- is supposed to adjust the Ph of soap (I have no proof on this, neither did not find yet the scientific evidence)
Looking at all the pros, there is no doubt the testers of Anne loved this soap!
Well, and I do love it too!!!
I never had a soap which makes such an excellent lather, one has an impression to be washing with a cream! And moreover – thanks to the fixative I added (see the recipe below), this soap smells fresh citrusy and it is literally the thing that wakes me up in the morning shower!
Lemon yogurt soap recipe
15.9 oz (450g) coconut oil
21.2 oz (600g)olive oil
6 oz (174g) white yogurt
7.8 oz (220g) distilled water
5.46 oz (155g) NaOH
0.21 oz (6g) EO lemon
0.32 oz (9g) EO litsea cubeba
0.18 oz (5g) EO lemongrass
1 TBSP rice bran powder (or cornstarch or flour) – the scent fixative
Instructions
1) Mix well white yogurt with the water and freeze.
2) Place the lye container to the a sink full of very cold water and ice and pour in the frozen yogurt+water
3) Very slowly – in small batches – add the NaOH into the frozen yogurt/water, while constantly stirring. Control the temperature of the solution so that it does not exceed 40°C (104°F), otherwise the milk sugars will caramelize and this will impair the whiteness of the soap.
It took me 15 minutes to dissolve all the NaOH and despite this, my solution finished a bit yellowish.
4) Melt coconut oil and pour it into olive oil. This will keep the temperature of your oils low.
5) Add lye+yogurt solution to the oils and mix until trace.
6) Add to your soap a mix of essential oils with rice bran flour (or other scent fixative) and stir well
7) Finally, pour in the molds – individual preferably – in order to keep the temperature and consequently the yellow color low.
To freeze or not to freeze? That is the question!
My question was – is freezing soap necessary, and how does this affect the color?
I poured soaps into individual plastic molds and one plastic log mold. I covered the top of the soap by baking paper to prevent soda ash.
I put:
- three molds into the freezer over night and in the morning placed them in the fridge
- the log mold and one individual mold were put directly in the fridge and
- the rest of the individual molds were left at the room temperature
I wanted to know, how the curing temperature affects the soap color.
Experiment results
- Soaps from the freezer (12 hours in the freezer, 12 hours in the fridge) were the whitest – although still yellowish – were also easy to unmold, BUT! after the soap reached the room temperature, they were very soft. I damaged them a bit by manipulation – like if it was cold butter. This was probably because the saponification reaction slowed down substantially at such low temperatures – this theory was later confirmed by the fact, that 24 hours after unmolding, each soap from this batch developed a strong layer of soda ash (by the reaction of unreacted lye with air).
- Soaps from the fridge (24 hours) were more yellow, but difficult to unmold – I had to put them in the freezer for 30 minutes. These were substantially harder than the soaps from the freezer. 24hours after unmolding, a thin layer of soda ash developed.
- Room temperature soaps (24 hours) were the darkest and also had to be put in the freezer for better unmolding. There was no sign of soda ash 24 hours after unmolding – the saponification has taken place almost completely.
I tried this recipe in 100% olive oil variant and it works, too 🙂
PS: Do you like my experience? How do you make your soap?
Answer by leaving a comment below the post!
Have a nice soapmaking day!
Evik
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References
[1] E. J. CLAR, C. P. HER and C. G. STURELLE. Skin impedance and moisturization. J. Soc. Cosmet. Chem. 26 337-353 (1975)
[2] Middleton JD: Sodium lactate as a moisturizer. Cosmetics and Toiletries 93: 85-86, 1978.
[3] Harding, CR, Bartolone, J and Rawlings, AV. Effects of natural moisturizing factor and lactic acid isomers on skin function. In: Loden, M and Maibach, HI, editors. Dry Skin and Moisturizers: Chemistry and Function. Boca Raton: CRC Press, 2000. p.229-241.
[2] Garg T, Ramam M, Pasricha JS, Verma KK. Long term topical application of lactic acid/lactate lotion as a preventive treatment for acne vulgaris. Indian J Dermatol Venereol Leprol [serial online] 2002 [cited 2012 Jul 8];68:137-9. Available from: http://www.ijdvl.com/text.asp?2002/68/3/137/12541
This entry was posted by evik on November 12, 2012 at 00:07, and is filed under soap recipes. Follow any responses to this post through RSS 2.0.You can leave a response or trackback from your own site.
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#2 written by admin 8 years ago
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#3 written by Doris Hag 8 years ago
Hi and thank’s for the recipe! I have made different kind of soaps until now (cold and hat processed) but never with milk or yogurt.
When you say “Mix well white yogurt with the water and freeze.” in the deep freeze or refrigerator and for how long?
Have you measured the pH of your soap? I try to make a soap for my face and my skin is sensitive, classical T and quiet dry on the cheeks with quiet some wrinkles. All the good and easy stuff! :p
Thank;s a lot!!-
#4 written by admin 8 years ago
Hi Doris,
better is to freeze it in the freezer, I don’t remember for how long – until its solid ;). 1 hour? But again, it is not necessary to deep freeze it, as it just affects the soap color. Last time I did just refrigerate and all went OK…
I did not measure the exact Ph of my soap, I just use the phenophtalein test and zap test, both OK, so it’s under 10. For face, I use soap with red argile clay (will be posting a recipe).
Works quite nice, my skin is mixed, some wrinkles, often dry after washing with hard water (if you have hard water, try distilled or soft water, it makes real difference!).But the lemon yogurt soap might work, too!
Best,Eva
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#5 written by Agnes 7 years ago
Hello Evik, just a quick question, maybe another silly one 🙂
I did this soap and it is very-very creamy and I adore it. But the smell has gone after a while. Do you think the reason is because when I did it it didn’t occur to me that you gave the essential oils in gramms. I did the soap with the same numbers but ml…do you think in measurments is the same? thanks in advance-
#6 written by evik 7 years ago
Hi Agnes, hummm, did you add the cornstarch, too? Mine usually keeps its smell for quite a while, actually. But, you are right, essential oils are lighter than water, somewhere between 85%-95%, this can be one of the reasons. Also, often the scent evaporates on the top, but when used, it reappears in the lower layers.
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#7 written by Agnes 7 years ago
But do you think the gramms and the milliliters are the same quantity? Because I did in milliliters but you gave the amount in gramms. And yes, I always add cornstarch to every smell, because loads of the smell dissappears and the essential oils are pricey…but just one thing to add to lemon smell: the only one has not dissapeared for me so far is the citrus eucaliptus which is a type of eucaliptus. The smell has nothing to do with eucaliptus it is a strong citrusy smell and it stays perfectly, no dissapearing.
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#8 written by evik 7 years ago
Well, sorry for not being clear, when I meant that essential oils are lighter than water, I wanted to say that given the fact that 1g of water = 1 ml, and essential oils weigh between 85-95% (but more often less than 90%) of what water weighs, that means that 1ml of essential oil weighs around 0.85 grams. This means 10 ml of essential oil is only 8.5g, which is less than the desired quantity.
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#9 written by N.B. 7 years ago
What is meant by “conserves the soap” is that some softer soaps waste away very quickly in the shower, especially if they get hit with a lot of water. It will seem like you’ve only used them a few times and they’re gone. Whereas soaps with sodium lactate are more durable and therefore will last much longer under the same conditions.
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#11 written by Waseema 7 years ago
Hey,
i am from india and a soap addict… your recipe for a yoghurt soap was the easiest and i gave it a try and let me tell you , i loveeeeeeeeeee this soap…………. it is rock hard, does not melt away quickly and the tip about adding cornstartch helped a ton with fixing the scent :)….. and yes its by far my favourite soap :)….
thnx a ton….
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Thank you for the inspiration to make yogurt soap! I also have Anne L. watson’s book but have not made any of her milk soap recipes. I am currently experimenting on putting anything I can think of into soap- fresh avocado, cucumber juice, aloe vera, banana, coconut cream, coffee, tea, clays, charcoal…. I love yogurt and your lemon yogurt soap sounds good to eat! :-p I hope to make one soon. 🙂
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#15 written by Joy 7 years ago
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Dear Evik,
This is a super-detailed description, and I liked your experimenting with the freezer-fridge-room temperature soaps.
This was the first time I worked with yogurt, and as I was confident enough thanks to you, everything went fine – I can hardly wait to unmold my lemon yogurt soaps. 🙂
Thank you for sharing this recipe and all the related information!
Greetings from Hungary:
Eszter -
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#19 written by Ayu 7 years ago
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#20 written by evik 7 years ago
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#24 written by Monica 7 years ago
Hi Evik
First of all I would like to thank you for the precious information you giving us through your blog. Some of them I knew and some not even hear about.
A while ago I was asking you what is going to happen if I will replace the yoghurt with whey.
But I decided to try it myself.
And here are the impressions;
I use whey as a liquid to dissolve the lye. The solution came out yellow-orange.
In first faze of boiling the soap( at low temperature of course ) the oils and lye-whey solution separated.
I taught I ruined everything but I kept on boiling and after a while it came together again .
After 4 hours of boiling I poured the soap into a big mould because it was too crumby and the colour was and still is awful. But I made peace with the idea I will throw it away but not before trying it .
And for my surprize the soap is wonderful on skin.
I never made a better soap in terms how it works on the skin.
It hydrates the skin and leaves a little humid sensation on the skin and the skin is not shiny at all contrary looks like you put some kind of powdery make up on it.
All in one I am more than happy with this soap but very unhappy with the colour.-
#25 written by evik 7 years ago
Hi Monica, I am so sorry I never replied to your whey question – I wanted to, but got busy and then forgot… thank you very much for the report. I did try whey two years ago in a soap that turned out to be excellent. I thought I posted the recipe, but I did not. Well, I will, as I loved the soap, too. The recipe contained coconut and olive oil. I used whey instead of water. I did not boil soap at all, I cold-processed it. If you hot process soap containing any type of sugars (milk, sugar, honey), it will turn brownish. That is why I never hot process soap with milk, yogurt or whey. I tried whey in combination with cream in this recipe: http://curious-soapmaker.com/avocado-soap-with-cream-gentle-peeling.html.
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#27 written by Jan 6 years ago
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#28 written by Jo T 6 years ago
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#29 written by evik 6 years ago
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#30 written by Nadine 6 years ago
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#32 written by Nadja 6 years ago
Hi, I made a very similar soap with Kefir I had left over. I replaced 100% of the water with kefir. I used rhassoul Clay in it and funnily enough EO’s of Litsea Cubea & Lemongrass 😉
I’m new to soap making and had no recipe that used yogurt or kefir but have made coconut milk & cream soaps last. When mixed it stank terribly “lyey” and I thought I would have to bin the mix. However I just poured it in individual moulds and left curing at room temp. I have just tried it today after 4 weeks curing and it’s absolutely fantastic. I’m in love. So much creamy leather & great slip making it perfect for a shaving soap!!! My skin felt moisturized like I’ve put body lotion on. I urge everyone to give this yogurt or kefir soap a go. Mine is a dark olive color due to the rhassoul Clay- Devine xx-
I think a lot of those thing smell horrible if its not plain water, read read read all the different forums and sights before you throw out any batch, I have been at it for almost 2 years now and feel new to soap making still, so much to learn and Ive had a few Ive wondered if they could be saved but Im stubborn and I hate waste and don’t have extra money to toss out on spoiled batch so I persist and if it doesn’t come out as a cold process I Cook it and make it into Hot process, so far I’ve never had to toss any and I’ve made over 20 batches getting ready for a farmers market soon. “Keep on soapin”
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#35 written by Bonny 6 years ago
Thank you for sharing your experiment results! You learn something new every day!
I make yogurt soap, too, and usually mix my lye water (50% of total liquid called for in recipe) as normal, add to oils and blend just enough to incorporate into the oils. At that point, I add my yogurt (the other 50% of liquid weight in recipe) to the oil and lye mixture, then blend until trace. That works really well for me, and I do not experience much if any yellowing of the soap which I usually keep in the fridge for 10-15 hours after molding.
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Ive been looking for something new to try, the 100 % olive oil with salt reminds me of the marsellle soaps ive seen talked about a bar based in Italy, all olive and a bit of salt and maybe baking soda, but its cooked for days or weeks. im trying that after this, since this has salt in it as well and I will be using all olive. I may try a small batch of this tho. have you tried all yogurt with no water?
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#37 written by Christy 5 years ago
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I have not tried yogurt yet, but I have been wanting to. I do make goat milk soaps. I usually leave them in the fridge for a week or more. I rarely have any problems with them being too soft leaving the soap this long before unmolding. I don’t think I would be able to leave it alone that long if it weren’t for the fact that I have a second fridge. I hate to wait to unmold.
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#40 written by Trudy De Luca 4 years ago
Hello, I was wondering if it was safe to keep that soap in your shower or do you have to keep it refrigerated. I made some avocado soap the other day and the top bits that I didn’t mash up real well kinda turned, so I’m trying to figure out if homemade soaps need to be put in the fridge after every use. You seem to be very knowledgable so I thought I’d ask. Thanks for you time! ☺️
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#41 written by evik 4 years ago
Hi Trudy! Normally, soaps do not need refridgerating at all – they can stay anywhere, the only thing that could happen is that they will go rancid, if you used rancidity prone oils. However – if you did use avocado in your soap and you did not mix it well – meaning you have junks-pieces of avocado fruit, then yes, the avocado in the soap will indeed turn mouldy. This is true for any fruit or vegetable in soap if it is not mixed in well (I mean if it remains in small pieces).
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#43 written by Poet 4 years ago
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#44 written by evik 3 years ago
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Thanks for sharing, it was nice to see what difference the various methods of curing the soap make. I have tried coconut milk and goat’s milk, but never yogurt. I guess I have something new to look forward to 🙂