…your guide to making natural soap and other bath & body products!
Lemon yogurt soap for fresh morning!
Do you want to know what happens with yogurt in soap?
And does yogurt soap need to be refrigerated?
How does this affect the soap color?
Read my experience below!
In one of my favorite books about soapmaking: “Milk Soapmaking” by Anne L. Watson, one recipe drew my attention: Yoghurt Parfait Soap, introduced by the following:
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 with sodium 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, 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.
 |
| Soaps after 24 hours in molds – top soaps are from the freezer – see how soft they were and how they were damaged b manipulation; middle row and first from the left in the bottom row – soaps from the fridge; bottom row – three soaps on the right – room temperature. The color differences are not seen well at the photo. |
 |
| Soaps 24 hours after unmolding. Bottom row – freezer soaps (see they are lighter, but with soda ash), middle row and first soap from right on the top- soaps from the fridge, top row three soaps from left side – room temperature soaps.. |
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
——————————————————————————————————-
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-
[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
- yogurt soap recipe
- yogurt soap
- lemon soap recipe
- yogurt soap recipes
- how to make yogurt soap
- lemon soap recipe cold process
- yogurt soap cold process
- yogurt in soap
- homemade yogurt soap recipe
- moisturizing cold process soap recipe
-
-
#2 written by admin 1 year ago
-
-
#3 written by Doris Hag 1 year 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 1 year 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
-
-
#5 written by Agnes 10 months 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 10 months 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.
-
-
#7 written by Agnes 10 months 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.
-
#8 written by evik 10 months 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.
-
-
#9 written by N.B. 10 months 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.
-
#11 written by Waseema 10 months 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….
-
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. :-)
-
#15 written by Joy 3 months ago
-
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 -
-
#19 written by Ayu 2 months ago
-
#20 written by evik 2 months ago
-
-
-
#24 written by Monica 1 month 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 1 month 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.
-
-
#27 written by Jan 3 days ago
-
- Comment Feed for this Post
I am Evik - the curious soapmaker!
I work in science and one of my passions are homemade bath and body products, because I love nature and think it is important what I put on my skin.
I always ask questions why and how, and search for scientific resources. Here I will share with you all the knowledge I gather... Let long live your bar of soap! 
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 :-)