I have included some methods that I personally use when making cold process soap in order to slow down trace. It is important to note that only with trial and error and experience will you become confident that your recipe and method will allow you enough time in order to make those lovely intricate swirl patterns. It is worth taking the time out to develop this and to find a recipe that works for you.
Well trace is when your oil, lye and water have mixed together to the point of no return. They have reached trace. This means that they will no longer be able to separate into oil, lye and water again. They have become soap.
If you use a stick blender it doesn't take much effort to achieve trace. Maybe 3 bursts with your stick blender and some stirring will bring you to light trace (where soap has consistency of single cream). However if you are soaping at cool temperatures you may experience false trace. This is where the mixture thickens but it hasn't properly saponified.
The soap batter often looks grainy. If you keep stirring then the batter tends to get thinner again and will “emulsify” or “trace.” This is the stage where you want to start colouring, fragrancing and developing your patterns. If you start out at a thicker trace your soap may be too thick to make your swirls.
When I first started to make soap I used to soap at really high temperatures i.e. 50 degrees centigrade (that's what all the books and articles told me). Now that is really hot. Too hot infact. Soaping at such high temperatures will cause you soap to “trace” really fast. Heat is a catalyst i.e. it will make a chemical reaction happen faster. Eliminate as much heat from your soap making as you can.
Soap at room temperature i.e. 25 degrees centigrade or lower. I personally let my oils cool down to room temperature and put my lye in the fridge until it's cold.
Now this may surprise some of you out there. You might be thinking: What if the reaction doesn't take place? How can the oil and lye saponify if the temperatures are so different? Well truth is in my experience the reaction always takes place and even though there are significant differences in temperature between the lye and the oils, saponification will occur. However it happens at a much slower rate. In fact sometimes it's so slow that you wish it would hurry up but this very slow tracing is necessary. It gives you plenty of time to make those beautiful patterns and swirls that make everyone say “wow, that's amazing.” And that is what we want right?
2. Fragrance/Essential Oils
Use a fragrance or essential oil/s that won't speed up trace. Some fragrance oils and essential oils contain substances including alcohols that can speed up trace. This can give you less time to make your beautiful swirls. You can avoid this by using fragrances/essential oils that won't speed up trace and will give you more time to work.
Some essential oils that won't speed up trace – Lavender, Citrus oils (Lime, Lemon, Mandarin, Litsea Cubeba), Vetiver to name a few.
Fragrance oils will behave differently depending on what they are made of. Some fragrance oils might have the same name but if they are made by different manufacturers they might contain different things and may affect trace in different ways. The fragrances to look out for are Floral fragrances – Lily of the Valley and Rose are usually culprits. Fragrances that have a strong alcohol/cologne type base. Some suppliers can be really helpful and will offer advice about their fragrance oils and how they affect trace.
It is a good idea to test your fragrance or essential oil blend first before you do your fancy swirls.
3. Adding Fragrance/Essential Oils After Adding Your Colours
To give yourself even more time you can separate and colour your soap before you add the fragrance/essential oil. Some fragrances/essential oils can speed up trace at varying rates. If your fragrance/essential oil doesn't speed up trace then you don't need to worry.You can add it before you separate your soap into colours. If your fragrance/essential oils might speed up trace then you can add the fragrance/essential oil after you have separated the soap uncoloured soap and have then added the colour. This means that you will have to separate your fragrance as well. So lets get started. Below is an example of how you would go about doing this.
My uncoloured soap weighs 2000g. I am going to have a 4 colour swirl and they are all going to use the same amount of soap. So.............
2000g / 4 = 500g Therefore there will be 500g each of uncoloured soap in 4 jugs. I then add the different colours to each individual jug of soap.
I am going to use 40g of fragrance oil. So I will need to put 10g of fragrance oil in each jug so that there will be a final total of 40g of fragrance/essential oil in my soap once all of the soap has been poured into the mold.
What if I have more of a certain coloured soap than another? Well we can still work it out but we'll have to do it by percentages. So..........
My uncoloured soap weighs 2000g. I am going to have a 4 colour swirl but I want more white soap than the rest of the other 3 colours. In fact I want 1000g of white soap which is 50% of the total batch. This means that the other 1000g will have to be divided by 3 for the other colours 1000g / 3 = 333g.
So if I have 40g of fragrance/essential oil I will need 50% or half of that for my white soap so 20g. The other half of the fragrance/essential oil will have to be divided into 3 equal parts. So.........
20g / 3 = 6.667g so about 6.5g – 7g for each of the jugs with 333g of coloured soap.
The stuff I've said may sound complicated, but if you really want to make an intricately swirled soap using a fast tracing fragrance/essential oils the tips above can buy you valuable some time.
4. Your Recipe
Use a recipe that is lower in butters and harder oils. So try to minimise butters, palm oil and coconut oil to name a few as their chemical make-up help to speed up trace. However try to get a good balance between you hard and soft oils so that you end up with a reasonably hard bar of soap that won't turn mushy in the bath or shower.
5. Soaping Cold
When soaping cold if your recipe contains too many hard oils they may actually start to solidify when you add the cold lye. A ratio of 45% hard oils and 55% soft oils is usually recommended. However I usually can get away with 55-60% hard oil and still soap cold as long as I am not using cocoa butter and limited amounts of shea butter (up to 10%).
Some useful notes – When adding your colour/fragrance to your soap stir in the colour/fragrance or stick blend but do it minimally to avoid speeding up trace. You want to aim to have soap that is like single pouring cream. The consistency shouldn't be grainy or very watery but smooth and still thin NOT THICK.