First, dissolve the potassium hydroxide flake into 70g (2.5oz) of water and set aside until cooled to between aprox 30/35 degC (86/95 degF).
Meanwhile heat the coconut oil and the second 70g of water together in a heavy-bottomed suitable saucepan until they reach aprox 80 degC (176 degF) (the oil globules will suspend in the water at this stage).
Take the water/oil off the heat and drizzle in the potassium hydroxide solution, gently stirring to blend.
Place the pan back on a low-medium heat and bring the temperature back to aprox 80 degC (176 degF), stirring continuously but gently until it becomes a uniform mixture. At first it will appear the water and oil are not fully blended, but after a few minutes it will gradually become a uniform and thicker consistency. DO NOT allow the temperature to exceed 82 degC (180 degF) or fall below 70 degC (158 degF), so remove from the heat periodically if necessary.
After approximately 15 minutes the mixture will become gel-like but still liquid. Before it gels completely remove from the heat and pour into a suitable container and leave to solidify and cool for 24 hours.
After a minimum 24 hours OR up to aprox 8 weeks max, this gel can be successfully turned into finished liquid soap as follows...
For the purposes of economy you can choose to use only part of the gel to turn into liquid soap, but for the whole amount you'll need the 250ml (1 cup) of water in the ingredients above. If using half or less, use proportionally less water.
Put the soap gel back into the heavy-bottomed pan and add 250ml (1 cup) of water, then over a low-medium heat and WITHOUT stirring, slowly and carefully 'scrunch' the soap into the hot water until you have a uniform liquid. Stirring will cause lather and you don't want too much later so 'careful' is the word to remember at this stage.
Add optional essential or fragrance oil. You may also choose to colour using a suitable liquid soap dye at this stage.
Finally, using a suitable strainer, strain the soap into a container to remove any undissolved soap or unwanted lather and pour into a suitable pump-dispenser.
The final viscosity of the liquid soap will alter with more or less water in the final stage and will only become apparent when completely cooled.GUIDE TO SAP VALUES