How to Make Cold Process Soap

These instructions are intended for use with any basic cold process soap recipe such as the many available on this website, but one is listed to assist you through your first ever soap.

Soap making is a time honoured occupation that goes back centuries. Techniques have changed a lot since the original methods, but the basics are the same – the combining of fats, oils and a caustic medium in the presence of water.
Cold process soap is made by heating fats and oils to melt them, we do not actually cook the soap. If the soap is cooked on a stove, oven or crock-pot it is referred to as hot process.
Soap making is much like cooking. We have ingredients, a recipe,  pots, pans, bowls, spoons, moulds and safety equipment.
Ingredients for most soap recipes need to be weighed, not measured.


The main difference between cooking and soaping is the caustic factor.  Because of this ingredient it is imperative that you wear goggles, gloves and closed in shoes as minimum safety equipment.  If you wish to go with apron, boots and hair net that is completely up to you.
Never use aluminium utensils as the caustic slowly dissolves the metal and you have aluminium in your soap. Wood isn’t too good either as it falls apart after a use or two and can leave you trying to pick splinters out of your soap before it sets. Plastic and stainless steel are the best items to use as they are non-reactive.

Making soap
Prepare a large pot big enough to hold the finished batch, 2 large plastic or stainless spoons, thermometer (infrared or glass) the ingredients listed on your recipe, scales, a mould and a measuring glass.
Weigh all your ingredients.

  • 333gm Coconut Oil
  • 333gm Palm Oil
  • 333gm Olive Oil
  • 124gm Caustic Soda
  • 300gm Water
  • 40gm Lavender Commercial Essential Oil
  • 50g of mica powder that’s 5% of 1kg of soap

     ***This recipe will make approximately 1kg soap – 10 x 100gm bars.***
Place all solid fats into a saucepan large enough to eventually take everything.  Melt on low direct heat and remove when it is all liquid. Add any liquid oils and stir well.  Allow to cool.
While this is underway take your caustic soda and sprinkle it into the water while steering gently with your spoon until all granules are dissolved.  This process will release fumes so ensure you do this in a well ventilated area as the fumes are unpleasant.  The chemical reaction that occurs in this process will cause the water to heat up.  Place your container somewhere safe (away from pets and children) while it cools down again

While your pots are cooling prepare your additives.  This will include the Mica Powder Pigment , scents, botanical etc.  Anything you are asked to add at trace now needs to be prepared so you are ready when that moment comes.

You are waiting for both pots to cool to about 40ºC.  This may not happen simultaneously.  If a pot is too cool put it in a sink of hot water to heat up.  If it is too hot, moving it around a cool benchtop may be helpful, or a sink of cool water if you prefer. Juggle the temperatures until they are about right.

Gently pour your lye mix into your oils in a slow constant stream as you stir the pot carefully with the second spoon in the other hand.  A stick blender is an invaluable tool for a soap maker. Hand stirring works well, but takes a lot of time. a hand stirred batch of soap may take several hours to reach its end. A stick blender cuts this down to a few minutes.  Plug in your stick blender, immerse the blades completely and begin.  Ensure the stick blender is turned off any time you wish to remove it from the soap.  Your oil mix will begin fairly clear, transition through cloudy to being completely translucent.  It will be getting thicker also.  When it is thick enough to support a little soap on the surface it is said to be at “trace”  It has thickened to the point where it can support some of the mixture on its surface before it sinks to the general mix. Don’t be too afraid you won’t recognise this. Once you have seen it you will notice it more readily next time. Trace will start off quite thin, but will thicken as time progresses and eventually become solid. Once you have reached trace, work with reasonable safe speed.

Add your desired Mica Powder Pigment you have choose , fragrances and botanicals at this time. Keep your first soap fairly simple as you are learning the process. 

Pour your completed batter into a mould of your choice. If your moulds are small or your home cool insulate your soap with cardboard and blankets to keep the heat in.  The chemical reaction-taking place within the soap generates heat that needs to remain for a few hours to complete the transition. If it cools too quickly the process may not be properly completed and will take additional cure time before it is ready to use. In warmer weather it is not such an issue, but on cooler days with small moulds it may cause problems.

In 24 hours the soap may be unmoulded. This soap will still be a bit soft and mildly caustic so please use gloves when handling your soap. The final stages of saponification take about a week to complete, and then needs a further three week minimum curing time to allow enough water to escape for the soap to last any length of time. If you are desperate to try your creation have a quick lather at the end of the first week, but i recommend leaving it to complete the cure before putting it to work full time.

Once you get the hang of soap making you may wish to venture out to new recipes or create your own recipes up using ingredients you would prefer.

Wishing you every success with your soaping. take your time and enjoy it.