[letsalcido]

I hadn’t come to this places for a bit now.

@David08848 I am trying hard to remember the name of that effect you saw in the soap. But it’s basically just telling you the PEG-40 HCO hasn’t mixed completely yet. You can see that effect when mixing glycerin into water.

What’s interesting is that the bottle on the left is cloudier, and the only difference is the PEG-40 hydrogenated castor oil? Same amount of fragrance and temperature?

I’ve slowly migrated to making a body wash not just with castile as there seems to be no way around the cloudiness. PEG-40 HCO has worked great at solubilizing my essential oils, making my gel absolutely clear. Given that your soap turned opaque later, I am thinking it must be a temperature issue. If it was due to the oils not being solubilized you would have seen the opacity change immediately after adding the oils.

Maybe someone else has more ideas.

[letsalcido]

I didn’t know that, so I did a bit of research and it seems that at the < 1% topical should be pretty safe. However, I suppose better safe than sorry. I am just curious to learn myself if this is something I should be cautious of now for my own products.

I found a study about a drug (Kenalog) that reported issues https://pubmed.ncbi.nlm.nih.gov/16508436/ and determined that at the current usage it does not present toxicity in rabbits.

That drug uses 0.99% Benzyl Alcohol as preservative and it’s injected into the eye https://www.aao.org/eyenet/article/intravitreal-kenalog-injections

It’s possible that whatever actives you put in the serum would be potentially more damaging and prompt the user to rinse thoroughly.

[letsalcido]

I’m no expert here but I’d throw a rheology modifier in your water phase to help stabilize the emulsion. xanthan gum, or a modified cellulose.

Are you trying to achieve a sprayable, lotion or cream consistency leave in conditioner?

Also, I do think oils are pretty high. It may leave the hair pretty heavy. 

 

[letsalcido]

Found an old post that has great information https://www.chemistscorner.com/cosmeticsciencetalk/discussion/751/preservation-strategies-for-natural-formulators

I am using 0.7% Phenoxyethanol and 0.7% Benzyl Alcohol/EHG (Euxyl K900 which is itself claimed to be broad spectrum). Benzyl Alcohol if I’m not mistaken complements Phenoxyethanol as it covers gram+ bacteria, yeast and mold. And EHG enhances activity. I also add 0.2% EDTA.

This is for my home made, personal use products and I have not preservative challenge tested my formulas, but so far I have not seen yeast or mold growth. 

I had come across another post about how Polysorbate 80 and highly pegylated compounds can bind and inhibit preservatives. So you may want to share your formula so a more seasoned chemist can guide you better!

[letsalcido]

Thank you @alchemist01 I skimmed through it and it’s interesting. I definitely need to read it properly.

I did some research and looked at the type of media USP 61 recommends, it seems that Tryptic soy would be fine to detect contamination with aerobic organisms. 

[letsalcido]

A few updates @David08848

I ordered some PEG-40 Hydrogenated Castor Oil as it is supposed to be an even better solubilizer than Polysorbate 20.

I also noticed that my soap is sensitive to temperature and gets very cloudy when cold. My uncle who has some experience with a shampoo he claims that Polysorbate 20 is cold sensitive, and solutions will turn cloudy. He had better success with PEG-40 HCO.

I did a test and that was true, I put a clear solution at room temperature of E.O./Tween20 in water and it turned opaque. I doubled the concentration of Tween20 and it resisted cold temperatures but the amount I had to use was too high. 15% or so. I’m hoping PEG-40 HCO can be used at much lower concentrations for the same result

Also, I didn’t know (newbie here) that liquid castile soap would turn very opaque (creamy) when cold. Is there a way to avoid this? Perhaps is the type of oils I used, and the solubility of the resulting soaps.

[letsalcido]

I am not in favor of this practice, but it makes you wonder. 

When you go to a barbershop, the barber uses the same tin of shaving soap for all his clients. Maybe that’s the logic that site is using. If a barber can use a soap on many clients, it is be safe to be sold used for someone else to enjoy.

[letsalcido]

What is almost anhydrous, can you share your current formula?
Maybe you could replace that amount of water with glycerine or a glycol.

What is the current pH if you dissolve the bar 1:1 in DH2O?

Since pH is the concentration of H+ in water, you can’t really control the external factors or the pH after it’s in contact with the water. Perhaps incorporating some Citric Acid into your formulation could help account for the surface layer of the soap becoming and staying hydrated for some time during use. You could test how much citric acid would be needed to bring the pH to 5 in a 1:1 dilution of your bar.

Maybe someone more experienced should jump in. But this is what I would try.

[letsalcido]

@David08848 

The salt/sodium is specifically for thickening purposes. There’s a limit to how much you can use before it causes the soap to break/turn turn opaque.

The polysorbate 20 is definitely needed for solubilizing your essential oils. The only essential oils I was able to use without it were peppermint and eucalyptus with menthol crystals (not sure if the menthol helps).

I fixed two of my broken batches (not shown in any pictures) by diluting with castile soap 1:1 and adjusting the thickness with salt and coco betaine for each bottle. The pictures are the result of this. In the first picture I added slightly more salt to the half batch on the right, and it caused it to break.

[letsalcido]

@David08848  I just started making cosmetics/soap. I have a background in biochemistry but no industry experience. What I shared is what I have observed, experienced and found by doing some research online.

I found a few sources, and this video has a great explanation for thickening soap with sodium. I believe she mentions that the maximum is 2% or you may break it (like I did by adding just a tad too much sodium) https://www.youtube.com/watch?v=y5z_zAnSEZg 

It will be a matter or titrating until you reach the desired viscosity and documenting how much you used.

[letsalcido]

@David08848 thanks for the compliment and sorry if my redaction was confusing! The two green washes are made from a failed batch that looked extremely creamy. I split that batch in half and fixed them separately with slightly different amounts of sodium. Those two bottles are the result. 

Same thing with the orange ones. Except I followed the same process for each so they look the same.

I would say that sodium is “natural”. I actually am using sea salt. I’m sure there may be some other minerals in there, but overall it should give consistent results. I would think that marketing your body wash as containing “sea salt” or “pink himalayan salt” could be attractive to the consumer. You’d just need to adjust it to each type of salt and make sure it doesn’t react in an unexpected way. of course, you can thicken with something else. Just my 5 cents.

In terms of process, I have been very impatient and mix all my additives to the castile soap within 5-15minutes from each other. I’m hoping to find a “fool proof” recipe that would be easy to scale up.

[letsalcido]

Thanks for your input @mikethair!

To address some of your comments:

- I understand that soaps are “self preserving”, but it will depend on concentration. In the bodywash I’m formulating I must have < 12% soap (1kg of oil in a 5kg batch, not counting the glycerin that’s the byproduct and it’s only 60% of the final product). If you take a look at most shampoos and body washes they do use preservatives given the extremely high water content. I in fact I had a batch with only 0.2% citric acid and 0.1% EDTA (bad idea, it gelled like crazy) that had bacterial colonies growing on it after 2-3 weeks (easily distinguishable because it had gelled and it looked like a petri dish). Also, the pH of my liquid soap routinely tests ~5.5 (perhaps I’m using the wrong kind of strips, and haven’t invested in a pH meter).

- Castile soap is easy to make, but in its pure form is very strong. It also lacks the cosmetic luxury that some people are looking for (thickness, natural fragrance, humectants). So I’m not trying to sell plain castile soap, but rather a more natural body wash. 

Here’s my finished liquid castile soap. Pretty good clarity, but it’s hard to enhance it for that “luxury” feel.

[letsalcido]

I’m developing a “natural” body wash with a castile soap base like yours, and having similar issues.

My take on this is that you’re on the right track. But there doesn’t seem to be a straight answer to fix your formula. You’ll have to experiment, as all ingredients will have a different effect on micelle stability.

These two bottles are from a “failed” experiment of a peppermint and menthol body wash.

Here’s what I did: I tested 1:5 oil to PS20, at 1% essential oil in pure castile soap. This created a perfectly clear mixture. I tried a 1:2, also clear but it took longer to clarify. I decided on 1:2 since eventually I would achieve enough clarity and I only had a small sample of PS20.

I did a 500g batch (300g is castile soap) and added my fragrance and PS20. All good till then, fairly clear after mixing. I could tell when left at rest it would completely clarify. I added 100ml of 5% salt solution. It broke and turned creamy/white. I continued with my recipe and tried to thicken it more with  Cocamidopropyl Betain. Still white.

I did another 500g batch, but instead of adding the sodium first I added the coco(…) betain. Broke before I added the sodium.

So I tried to fix it. I figured that the electrolytes and anything that may alter the viscocity of the soap (preservative, type of essential oils, menthol) is actually putting ionic stress on the micelles and eventually causes it to break. But this is not irreparable, I tried to fix one of the 500g batches and basically halved the concentrations of essential oil and polysorbate by doing 250g of my broken batch and 200g of fresh castile soap + 50g of other stuff. That immediately turned clear again, and It became thicker too (hello micelles!). I added glycerin (10g) and made it even clearer, but more watery. Added the required Phenoxyethanol amount to get it to 1% and i turned a bit thicker but not quite there. So I adjusted it further with Coco(…) Betaine (5g?) and 1g of salt in Q.S. water. Left bottle in the pic was the first fixed batch. The one on the right, I did basically the same procedure but I tried adding a tad bit more salt (bad idea) and it turned a bit more opaque but still seems to be that it will be stable and won’t separate, it’s just not emulsified fully like the clear one.

Another pic of another creamy looking batch I fixed this morning which has orange essential oil (citrus oils are hard to get clear apparently):

What I learned from this:
* Anything that alters the viscocity of your soap (interacts with micelles) can break the emulsification of your essential oils and make it look creamy.
* even without essential oils, your soap will turn creamy and slimy if too much sodium is added. 
* if it looks creamy and has oils in it, it will separate eventually
* Each essential oil is different and will behave differently.
* Any other actives in your formula can destabilize it.

If you are set on the preservatives and fragrance you want to use, I recommend doing a “titration” to find the balance. You’ll notice that you may achieve a peak thickness before adding a single drop of anything and it breaking. 

If you’re curious, my base castile is 60% Olive, 40% Coconut, approximately 1:4 oil to water ratio.