Susanne's Crafty Corner: Cosmetics

Tutorial: making transparant glycerin soap (page 1)

If you thought that transparent glycerin soap is always melt & pour and can’t be made at home from scratch, you’re wrong. You can certainly make it, and this tutorial is about how to do it. Why take the trouble? Well, transparent soap looks very cool and can also be used for special effects in “normal” CP or HP soap. And this without the chemicals there are in M&P, when making it yourself, you definitely know what goes in it!

Making transparent glycerin soap is something for the more experienced soaper but really fun and worth the try. If you don’t have any hot process experience yet you should really try that first, as that is needed for the first steps of making transparent bar soap. You can find a tutorial here and links to others over here.

Recipe

Not all oils can be used for making a transparent soap, so you will have to make a special recipe for the occasion. From soapmaking-101 I got the following list about the clarity of soap from several oils. This was concluded from tests in liquid soap, but I believe this also applies to making clear glycerin soap:

  • Castor oil:         thick lather, mild and makes a very clear
  • Olive oil:            close, persistent lather, mild and makes a clear soap
  • Almond:            Close, persistent lather, very mild and makes a clear soap
  • Apricot kernel:   medium lather, very mild and makes a clear soap
  • Avocado:           dense lather, mild and makes a clear soap
  • Canola:              Medium lather, mild and makes a clear soap
  • Coconut:           foamy bubbles, harsh and also makes a clear soap
  • Palm:                lasting bubbles, very mild but makes a cloudy soap
  • Palm kernel:     large bubbles, harsh and makes a clear soap
  • Tallow:              lasting thick bubbles, very mild and makes a very cloudy soap
Stearic acid also makes a clear soap and helps to harden up when the rest of the oils chosen are rather soft. Stearic acid does have the tendency to hasten trace, for this reason melt it separately and add it at medium trace. Don’t use it at more then about 3.5% of your oils since it can cause “drag” like beeswax can have when used in soap. Other oils my possibly also give transparent soap, just haven't found information on them.

When making transparent soap only a very small lye discount is taken since excess oils make cloudier soap. Take a lye discount of approx. 1 %. Besides oils, water and lye a few other ingredients are needed to make this type of soap. Once the soap is cooked ready, it is made transparent by dissolving it in alcohol and adding a sugar-glycerin mixture later on. You could also dissolve soap scraps and leftovers this same way, but because of the superfatting issue this soap won’t be as clear as soap made from scratch with a special recipe. Could make nice effects when used with “normal” CP or HP soap though.

How much alcohol?

After doing some calculations with recipes and instructions from the web, I found that most people use a 97% strength ethanol solution between 30 and 35% of the amount of oils. To be at the save side I suggest you go for the 35% amount to be sure you get the soap completely dissolved. If you can’t find a 97% strength alcohol solution you will have to recalculate the amount of water used to make the soap. The more water in the soap, the less clear the soap will be. Say you can find 70% alcohol (very strong vodka or something), this is how to recalculate the amount of water to use:

In a recipe calling for 1050 g oils and 300 g water, you would need 35% of 1050 = (1050 / 100) x 35 = 367.5 g of 97% alcohol. In that amount there is (367.5 / 100) x 97 = 356.5 g pure alcohol. To get that amount of pure alcohol with a 70% alcohol solution, you would need (356.5 / 70) x 100 = 510 g of the solution. This is 510 – 367.5 = 142 g more liquid then in the original recipe. To balance it out you would have to subtract 142 g from the amount of water used to mix the lye with, making it 158 g. Make sure though that the amount of water used is at least 1,2 times the amount of lye or it won’t dissolve completely and you will have trouble completing the saponification process in what begins as basic HP.

When using lower strengths of alcohol solutions you will be venturing into the realm of water discounting, so be extra careful with the (stronger) lye solution. To avoid this trouble and make this a bit easier for yourself work with the strongest alcohol solution you can possibly find.

Sugar & glycerin

At certain point you will add a sugar solution and glycerin to the soap. That makes that transparent glycerin soap is actually only partially soap. The glycerin makes sure the soap is still soft for the skin even though only a tiny amount of lye discount / superfatting is used.

Again from comparison of recipes available on the web I deducted that sugar should be used at a weight of approx. 28% of the amount of oils. Make a sugar solution by adding just enough hot water to the sugar as is needed to completely dissolve it. Glycerin at 15 % of the amount of oils should do the trick.

In short:

Your recipe should consist of:

  • Oils (choose from Castor, Almond, Apricot kernel, Avocado, Canola, Coconut, Palm kernel oil and stearic acid (not more then 3.5%) for a clear soap)
  • 97 % alcohol at 35 % of the amount of oils (or recalculated amount for a weaker alcohol solution)
  • Water according to calculator (minus amount to balance out a weaker alcohol solution then 97 %, total amount to be at least 1.2 times the amount of lye)
  • Lye for a 1 % lye discount
  • Glycerin at 15 % of the amount of oils
  •  Sugar at 28 % of the amount of oils, dissolved in as little hot water as possible.

And of course the usual soaping stuff like protective gear, pots &tools, molds, fragrances and coloring.

For the process, please go to page 2 of this tutorial!

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