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Supermarket Soap

Updated: Nov 13, 2021

An unglamorous name for a delightfully indulgent cold process soap. Feel free to give it a more imaginative and fitting name!

This cold process soap is made using only oils I found in the supermarket and at my local convenience store. In fact, if you don't want to use colours or fragrance in your soap, everything in this soap formula can be found without having to buy ingredients online or go to a specialist supplier.

What About Soap Qualities And Performance?

In formulating this recipe, quite by chance, the oil blend and proportions I decided on hits the magical 'ideal' INS no. of 160, as proposed back in the 1930s by Dr Robert McDaniels in his book "Essentially Soap". However, we don't want to get too hung up on INS values (and definitely not here because that's a subject in itself that requires a deep dive), as there are many other ingredients that affect both the quality and performance of the end soap besides the oils. There is no such thing as a 'perfect' soap, not least because what we want from a soap varies from one person to the next. However, most people will agree that a good soap should have bubbles and lather, not be too drying nor too oily or sticky, and be reasonably hard at the end of the cure. This formula delivers on all counts.

The inclusion of yogurt (which contains lactic acid) in this soap contributes to the hardness. Lactic acid combined with sodium hydroxide undergoes a chemical reaction that turns it into Sodium Lactate, an additive used by many soapers to improve the hardness of their soap and make it easier to unmould. As I am using Greek yogurt, which contains some fat, it will also contribute to the skin conditioning qualities of this gorgeous cold process soap. The other ingredient I use here is milk powder. This contains lactose, a natural sugar found in milk, that will increase the overall bubbliness and lather. Dried milk powder has around 38% lactose, so using 10g (as I do in this recipe) is roughly the same as adding a softly rounded (not heaped) tsp of sugar.

A Quick Word For Beginners

If you are brand new to soap making, it is very important that you weigh out all the ingredients accurately and don't substitute any of the oils. The reason for this is that each type of oil requires a different amount of sodium hydroxide to saponify effectively, so the amount of sodium hydroxide is calculated specifically for this amount and blend of oils. Substituting the oils could make your soap either too caustic and therefore liable to burn your skin, or the oils won't turn into soap and you'll end up with an oily mess that is part mushy, semi-formed soap and a lake of liquid oils.


This soap recipe uses 1 Kilo of oils and yields 8 -10 good sized handmade soap bars when fully cured. For the method, please watch the accompanying YouTube video here.

Oil Blend

450g Coconut Oil

100g Corn Oil

100g Grapeseed Oil

100g Avocado Oil

100g Rice Bran Oil

100g Unrefined Rapeseed Oil

50g Castor Oil

Lye Solution

147g Lye (AKA Caustic Soda, Sodium Hydroxide, NaOH)

200g Water


(Optional But Recommended)

10g Milk Powder

100g Yogurt

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