So........ I have been working/experimenting with Liquid Soap Making for the past 2 1/2 years and while I love the process and everything that I have learned along the way, it is far trickier to accomplish successfully and consistently than cold process soap making. Fortunately, the ingredient cost is minimal so I have not lost too much in materials (only time) during these past 2 + years of learning, experimenting, getting frustrated and achieving success. (Updated 5/2014, 7/2014)
1. Start with a pre-made paste (I used Brambleberry's 100% Castile Paste) to understand the dilution process. Since this is a 100% Olive Oil paste, it will take a lot of distilled water to dilute allowing you to see what a skin is and how to effectively continue to slowly add more water until full dilution. Because it is 100% Olive Oil, you can also experiment with using non iodized table salt (dissolved in distilled water) to thicken your soap. Dilution should be done very slowly by adding small amounts of boiled distilled water at a time, allowing the paste to dissolve into the water, then add more water if necessary. Patience is key to avoid over dilution and too thin a soap. Every formulation you create will have different dilution amounts. The method you use to create the soap will also affect the amount of dilution water needed to fully dilute your paste to the desired consistency.
2. Use a reliable calculator that takes into account the 90% purity if KOH. These include Summerbee Meadow (also allows dual lye calculations), Brambleberry and Soapcalc. Summerbee Meadow and Brambleberry are calibrated to a slight lye excess and you will probably get the same calculations from them. Soapcalc has two options, one for straight KOH and one for 90% pure KOH - each will give results slightly different than the first two.
3. Clear soap tested after a 3 hour cook (or any amount of time) does NOT mean you do not have excess KOH in your paste. See #3. Excess KOH is the result of using a lye excess in your formulation.
4. Phenolphthalein Drops are a my most important tool for testing for excess lye and if the soap is done. Some people use the Zap test (place a bit of paste on their tongue to see if it zaps like a 9V battery placed on the tongue). Soap paste is done (no excess lye) when the paste stays clear or very, very pale pink after adding a drop. You can also titrate a diluted sample which is a bit more accurate. This does not mean your pH is low. True liquid soap will have a pH in the range of 9.2 - 10.5. The more you superfat you soap, the lower you pH may be, but you will have problems with too much of a superfat in liquid soap. You can have a clear test of drops and a high pH soap so always test your pH with a reliable pH meter too on a very diluted room temperature sample. Testing for a lye excess is far more important than just testing your pH.
5. Use Digital pH Meters on cooled, highly diluted soap (1% solution of paste in distilled water) when you need an accurate ph reading NOT pH papers or test strips. pH is affected by temperature and concentration and readings while soap is hot or highly concentrated will be lower than readings at room temperature. It is not the pH that is lower, but just the accuracy of the readings. It is very hard to troubleshoot liquid soap problems without an accurate pH reading and papers/test strips cannot do that as they only give a range. There can be a very big difference in how your soap looks and behaves at a pH of 9.5, 8.7 and 8.2 and troubleshooting this can be hampered when you do not have an accurate reading. Please see the post on pH readings, lowering pH
6. Thickeners. I use only non-iodized table salt, HEC (Hydroxyethyl Cellulose) or HPMC (Hydroxypropyl methylcellulose) to thicken my liquid soaps and shampoos when needed. All work well (salt for 100% olive oils or those very low in coconut oil) and HEC and HPMC for the rest. HPMC works very well at very low rates (.5% - .7% depending on how thick your soap is to begin with) on mixed lye soaps (those created from both sodium hydroxide and potassium hydroxide). HEC is wonderful when you want to insure that your soap will maintain its clarity. HPMC at amounts greater than 1% have caused a bit of cloudiness in my previously clear soap - but again, you need less of the HPMC in dual lye soaps and in that case, it is not an issue as clarity remains at the lower levels of usage. Note: there are other thickeners out there, but these are the ones that I have experience with and use.
7. Neutralization - neutralization when referring to liquid soap is not getting your soap to a neutral pH (7.0). It is the process of removing any excess lye that exists in your paste. Older formulations and methods of creating liquid soaps used a lye excess to account for impurities in KOH to insure all oils were saponified and a clear soap was achieved. That excess lye was then neutralized with the addition of borax, boric acid or citric acid after dilution. The calculators we now have access to take into account the impurities in KOH to give us much more accurate lye amounts needed to saponify our oils so an excess is no longer necessary. Using these updated calculators, you can even superfat your formula at 1 to 3% and still have a clear soap without the need to neutralize. Keep in mind too that clarity is also affected by the oils you choose. Some oil/butters have unsaponifiables or are high in palmatic and stearic acids that will create a cloudy soap and should not be used or used in small amounts if you want a clear soap. Oils and ingredients with animal fats (tallow, lard, goat's milk) often create a soap that has a pearlescent effect to them.
8. If adding Citric Acid, it should be added when the water/citric acid solution is super hot AND the diluted soap is hot. You may see tiny white curdles or streaks when first added, but if you do not use too much, those will incorporate back into the diluted soap. Be very, very careful lowering the pH with citric acid as too much and it will cloud your soap and take it out of solution (separation will occur). I also find that after liquid soap sequesters a bit, the pH naturally lowers on its own.
9. Plain fresh seltzer water (not a bottle that has been opened and sat around for a day or so - it will have lost too much of the carbonation) will neutralize excess KOH during the dilution phase. I am still experimenting with this but my tests show that 1 ounces seltzer water per 12 ounces paste reduces the PH by .1 - .15. Would love to hear what others have experienced with using seltzer water as I am still experimenting with this.
10. If your soap separates out after diluting because your ph got too low by adding too much citric acid or other neutralizers/ph adjusters (nothing is more frustrating than to pour a batch of just diluted, beautifully clear soap into your storage container only to see it separate out - a layer of thickness on the top - the next morning) - heat the soap back up, dissolve a bit of KOH into distilled water and add it back to your soap. Let cool and sit again. If it still separates, you can repeat the process. Add just a little bit at a time as you do not want to end up with a now caustic soap with excess lye.
11. I still cannot get a completely clear goat's milk soap. They develops a sludge that settles to the bottom and a pearlescent effect in the soap. Coconut Milk is far less problematic. The sludge can be strained out using a mesh strainer and several layers of paper towels. Goat's Milk liquid soap will be much darker than soaps not make with goat's milk. Many have tried to cold process the goat's milk soap paste to prevent it from heating up too much to try to reduce the dark appearance (this is not an issue with coconut milk). If cold processing goat's milk soap paste, be aware that when you dilute the paste, if you use too much heat, you will be further cooking your paste and it will darken up anyways. ETA (6/2014) - I have finally come up with a way to get as clear a goat's milk soap as possible and have a tutorial of this method posted.
12. You can use a variety of liquids to dissolve your KOH. Distilled water, heated glycerin, milks or any combination. Using glycerin for all or part of your liquids speeds up the process to get you to your cook time (trace) much faster. My 50/50 formulations (50% distilled water and 50% glycerin) get to the cook stage within 10 minutes . When using milk for part of the liquid, I like to add them cold at trace.
13. You can use a variety of methods to make your paste. The three I use to dissolve your lye are 100% distilled water, a mix of distilled water and glycerin, and 100% glycerin. You can use other liquids to dissolve your lye, but take good notes to see how they affect your finished soap. If you use the mixed water/glycerin methods you can add your glycerin to your melted oils as long as you have enough water to fully dissolved your lye(s). I shoot for a 1:1.1 ratio of lye:water with the remaining liquid amount in glycerin added to the oils. I have tutorials for all three methods.
14. Fragrance and Essential Oils. Another thorn in my side.......... Again, nothing is worse than having a beautifully clear diluted liquid soap cloud up or separate out because of the fragrance oil or essential oil added. Always test a small amount of diluted soap (4 or 5 ounces) with the fragrance or essential oil. Some will cloud your soap, some will thin it out, some will thicken it. Fragrance and Essential Oils are not water soluble so I add them to warm to hot soap. Some people use polysorbate 80 to make them water soluble. So far the following have worked well for me without a solubizer:
- Lavender EO
- Peppermint EO
- Rosemary EO
- Fresh Mango (Brambleberry)
- Tropical Vacation (Brambleberry - clouds up at first and takes several days to clear)
- Lime EO
- White Tea and Ginger (Brambleberry)
- Awapuhi (Elements Bath and Body)
- Coconut Cybilla (Brambleberry)
- Apricot Freesia (Wholesale Supplies Plus) - this is my absolute favorite.
- Dancing Waters and April Showers (Wholesale Supplies Plus)
- Lime Ginger (Elements Bath and Body)
- Bamboo Sugarcane (Elements Bath and Body)
I do wish suppliers would have more information about how their fragrances perform in liquid soap like some do for cold process soap. Knowing how a fragrance performs for the product you are making saves so much time and energy. ETA - Brambleberry is now indicating how some fragrances perform in liquid soap!!!
15. It is easy to add water soluble additives to your soap/shampoos. I add panthenol and proteins and even water soluble shea butter to my soaps after/during dilution. Just be careful with adding any botanicals and proteins and research which preservatives you might want to consider when adding botanicals. You can also add these ingredients in their powdered form during dilution (dissolve into the dilution water) - but they should be dissolved in water prior to adding to your soap. Liquid forms are typically heat sensitive so consider adding those when the soap is cool.
13. The more coconut/babassu oil in a formulation, the more the initial mixture will puff up during the emulsification process before you cook the paste - so plan accordingly to make sure your pot/crock pot is large enough. This is probably due to the nature of coconut/babassu oil in creating a more bubbly finished product - but not sure. Those high in these hard oils will have a tendency to "Volcano" or puff up enough that it will overflow your pot - keep an eye on it and never leave these pastes to cook without supervision.
14. Preservatives - there is a lot of discussion regarding the need to preserve liquid soap. Many people will not use preservatives and many will always use preservatives. Liquid soap naturally has a pH of 9 - 10. Oftentimes the pH will be lower than that due to intentional lowering of the pH or by the additives used during/after dilution. Most bacteria will not grow in a high pH product (over 10) but the lower the pH, the higher chance that the environment will be conducive to bacterial growth. Mold and yeast will grow at higher pH levels than bacteria. Also, many additives create an environment more conducive to bacterial growth (proteins and water soluble extracts). I have been advised that it is a good idea to preserve your soap if the pH is lower than 10. The problem then becomes which preservative to use for liquid soap. Many preservatives have pH restrictions that do not go high enough for our alkaline soap products. There are two that I will use - Suttocide A which is a broad spectrum preservative effective up to a pH of 12 and Liquid Germall, also broad spectrum, which indicates a max pH of 8, but experts in the field of cosmetics have indicated that it is effective up to a pH of 10. Both are used at low percentages and both are heat sensitive and should be added to cool soap. Suttocide A will react to citral which is an ingredient in citrus Essential Oils and Fragrance Oils and it will turn your soap from pink to deep red. Also, good manufacturing principles and using clean, disinfected equipment will play a role. More information on preservatives can be found here. This is an excellent resource for preservatives in general.
15. Soap concentration and dilution - How concentrated you want your finished soap to be will affect your dilution ratios. Many people dilute there soap only with enough water to try to create a thicker finished soap. These soaps are typically very, very concentrated and a little will go a long way and it is very possible that you may be wasting your soap with such high concentrations of paste. I prefer to dilute the soap to the concentrations that works for the intended purpose of the soap (body wash, facial wash, cleaning soap) and then thicken it up to the preferred viscosity for the purpose of the soap. When I make body washes, the dilution ratios are such that a small amount of soap on the scrubby (about quarter size dollop) is plenty to fully wash the entire body - but, this leaves the soap on the thin side. If I had increased the concentration to start with a thicker soap, I would be wasting way too much of it as just a small dollop would be more than needed for a shower. Thus, I will dilute these to the proper concentration of finished soap, then thicken them up with appropriate thickeners, some of which add extra benefits to your soap.
That's all for now. I will update this post as I continue with my Adventures in Liquid Soapmaking.......
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