Cold Process Soap Making

In the cold process, lye is added to cold water, and the resulting chemical process, along with your warm fat and oil mixture, generates all the heat necessary. The cold process is not very difficult... just take it one step at a time and you'll have no problems.

Before you begin making any soap, it is essential that you read the entire recipe to make sure you have all of the ingredients on hand. This is good advice for all soap making, not just the cold process.

Safety is also essential, and when you are working with caustic lye, as well as with highly flammable fats and oils. Always follow the safety precautions outlined above. Remember, soap making is relatively easy and fun, but becoming lax about safety can damage your work area and be dangerous or even deadly.

Cold Process Recipe

For the purpose of these basic instructions, we will use the following ingredients:

Basic White Soap

74 ounces tallow
32 ounces blended vegetable or olive oil
3 ounces cocoa butter
14 ounces lye
41 ounces cold water

Step 1: Using one of your pitchers, weigh the lye to ensure you have the right amount. You can choose to place the empty pitcher on the scale and weigh it or you can place it on the scale and zero your scales.

Step 2: Using a different pitcher, weigh out the correct amount of water. It is best to use distilled water or water that has been de-mineralized. Another good choice for soap making is rainwater.

Step 3: Place the pitcher with lye on a flat and protected surface in preparation for adding water.

Step 4: Slowly add the lye to the water. You will see a reaction right away as the lye starts to make the water hot, and it is important to avoid splashes.

IMPORTANT: YOU SHOULD NEVER ADD WATER TO THE LYE!

The resulting splashes, steam, and boil-over will be very dangerous!

Step 5: Stir the lye and water mixture gently with a spoon until all the lye crystals have dissolved. Lye that is not dissolved may cake at the bottom of your pitcher. The lye mixture should now be around 150 degrees Fahrenheit. Once all the crystals have dissolved, set the mixture aside to cool.

Step 6: Weigh the tallow, oil, and cocoa butter in your cooking pot (provided your scale goes high enough to weigh the pot, or can be zeroed with the pot on it). Heat the fat mixture until it melts, stirring to ensure all of the oils are mixed well.

Step 7: Once you have a liquid fat mixture, it is time to start matching the temperatures of both mixtures. If your lye mixture has cooled to below 100 degrees Fahrenheit, you must heat it by placing the pitcher in a tub of warm water.

If it is still above 100 degrees Fahrenheit, use a tub of cool water to cool it down. The fat mixture should have gone above 100 degrees Fahrenheit, so you can use the same cool bath method to reduce its temperature. Continue stirring, however, to ensure that the mixture does not re-solidify.

Step 8: Once you have both of your solutions at 100 degrees Fahrenheit, you are ready to mix them. Getting the two exactly right will take a lot of practice, but it should become easier the more you do it.

Even though it may be frustrating, it is important that you resist the temptation to mix the two solutions together when they are not at the correct temperatures, which can wreck your entire batch of soap!

Step 9: Pour the lye mixture SLOWLY into the fat mixture, stirring constantly as you do so. If you see the lye mixture on the surface of the fat mixture, stop pouring until the lye is absorbed. You can then resume mixing.

Step 10: Once all the lye mixture has been absorbed into the fat mixture, continue stirring gently. It is important that the fat mixture be kept in motion so that it does not start to solidify too soon. Your soap mixture should begin to thicken, becoming opaque and grainy.

Step 11: You should continue to stir until you see trailings, which will look like instant pudding that has been stirred and folded back in on itself (see picture below). To test for trailings, also called tracings or trace, simply pull your spoon out and let some of the liquid soap trail across the surface.

If your stream of soap mixture appears to stay on the surface, the mixing process should be complete. Trailings can be somewhat hard to spot, especially in the more advanced soaps containing vegetable or fruit oils (more on these later).