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Testing Fragrances Part 2

In part 1, I discussed vanillin discolouration, but it is quite possible to have a fragrance with 0% vanillin that will still discolour your soap. Fragrances are comprised of many different components, some contain 100 or more ingredients to make up a unique scent. Any of these can affect the colour as well as other aspects of soap, which is why not all fragrances are suitable for soap making. Fragrances that are considered safe to use in soap making must be skin-safe, suitable for cosmetic use and have undergone strict testing to comply with international standards. Only source your fragrances from responsible distributors, such as Pure Nature, who can provide safety data and certification from their suppliers.

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Even if the fragrance doesn’t contain vanillin, they can still cause discolouration, as the different shades of white of these soaps show.

To create a fragrance, different essential oils, resins, as well as natural and synthetic aroma chemicals are mixed together to a unique blend. Unfortunately, in most countries, fragrances do not need to list their exact constituents, because it falls under ‘trade secret’, so we usually don’t know what exactly is in them. Certain components will change the colour of your soap, just like vanillin, but because we don’t know the exact make up of the fragrances, it is difficult to pinpoint which component causes discolouration or even to predict what a fragrance will do to the soap.

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The top soap was an early test for one of my tutorials and instead of remaining white, turned a rather bright yellow during the curing time. The fragrance contained no vanillin, yet still caused significant discolouration.

The most common discolouration from a non-vanillin component is off-white, ivory or a creamy colour, although there are other possible colours as well. Oakmoss and amber, from Candlescience, for example, can cause your soap to turn a shade of mauve.

Then, there are some fragrances or components of fragrances, which have a natural tint to them and can also discolour your soap. For example, orange essential oils range from yellow to bright orange in colour, which may cause soap to turn yellow. In general, my rule of thumb is if the fragrance is not clear, that’s a warning sign! But that doesn’t mean that all tinted fragrances discolour, just like not all clear fragrances won’t discolour. And to complicate matters further, your soap recipe, the oils you use, your soaping method and the temperature can all have an influence as well. This is why you often get conflicting reports of fragrance discolouration. The only fail-proof method is to test a fragrance using the exact recipe and method yourself, to be absolutely sure of no discolouration. However, in most cases, slight changes don’t matter that much, and for the extreme discolourations that vanillin causes, looking up the vanillin content, or reading the fragrance reviews are often a good help. Or you can go for one of the water white fragrances.

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Although not a water white fragrance, the discolouration is only subtle and doesn’t distract from the overall design.

Water white fragrances are fragrances that are clear liquids, have 0% vanillin content and cause no discolouration.  There is no standard that labels these fragrances as such, and the only way to know which fragrances are water white fragrances is usually from testing or from test results that other soapers have done for you.

Here are four Candlescience Skin-Safe fragrances that can be considered water white fragrances:

And lastly, another option is to add titanium dioxide to your soap. Titanium dioxide acts as a whitener in your soap, although it will only work on light discolourations. It won’t magically turn your brown soap into the pure white! The good thing is that you only need a tiny amount to counter the discolouration, I use a maximum of half a teaspoon in one kilo of soap. Don’t use too much or you’ll end up with the unsightly glycerin rivers. Incidentally, titanium dioxide added to micas can make the colours pop, stand out more!

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Testing Fragrances Part 1

Why test fragrances? Fragrances can wreak all sorts of havoc in soap making due to the many different components that make up a fragrance. Fragrances can discolour soap, can raise the temperature during the saponification process, can increase acceleration and cause seizing, just to name a few possible problems. But don’t think essential oils are any different, these issues can also arise when using particular essential oils! Here, I’ll be discussing why and how these problems are caused and how to prevent them. And as an extra bonus, I’ll post the results of the Candlescience Skin-Safe Fragrances, available from Pure Nature, that I’ve tested in the past month, to help you choose the right fragrance for your next project.

The main problem for soap makers is discolouration in soaps. The discolouration is usually caused by the ingredient vanillin, which the primary component of the vanilla bean extract, the bit that gives vanilla its unique scent. Fragrances that contain vanillin will inevitably turn to brown. How much the discolouration and how quickly a soap will turn brown, depends largely on the percentage of vanillin a fragrance contains. Fragrances with a high percentage of vanillin, 10% or more, will turn to a dark brown, whereas those with only a small amount, less than 1%, will only discolour slightly and often only after some time has passed, which is why fragrance testing takes a while. You only know the full extent of the discolouration after a soap has been completely cured. Incidentally, discolouration also affects melt and pour soap bases and other skin care products. The reason for the discolouration, as it often is, is caused by the villain oxidation. Oxidation occurs when chemicals react with the natural oxygen present in the air. You could, of course, try and wrap your soaps airtight, but that would only work for a limited time and only with melt and pour soaps and lotions. Cold and hot process soaps need to cure, which can only happen if they’re unwrapped. And curing causes discolouration…. see the dilemma?

 

In the above two pictures, you can see vanillin at work. The picture on the left was taken after 1 day of curing, the picture on the right after 5 days. Discolouring will continue until the whole soap has become the same colour as the edge. Vanillin discolouration is a totally natural process, and you cannot prevent it from happening. But there are chemicals that can slow this process down. They don’t completely eliminate the discolouration, but can stabilise the fragrance and postpone the discolouration for several months. Now if you’re like me, I’d like my soap to keep looking like it did when I gift or sell it, and having it turn brown in someone’s pretty soap dish after half a year seems a bit misleading to me. Nevertheless, if you would like to explore this option, the product is called Vanilla Colour Stabiliser, and it works by counteracting the oxidation of the vanillin, but as I mentioned before it won’t last for ever. The longest I have seen it working was about half a year.

The much better solution is to work with the discolouration. If you know the fragrance will turn your soap in a shade of beige, caramel or brown, use this in your design. You can leave a small portion of your soap unfragranced, which keeps parts of your soap white. For example, adding a white swirl or white layer in your otherwise brown soap. A fragrance that only discolours slightly can be ‘coloured over’ with other colours, such as oranges and reds. However, remember that some colours don’t mix well with brown shades. Green, for example, mixed with brown will result in a rather unpleasant shade. And lastly don’t forget that often those fragrances that contain high percentages of vanillin, tend to be fragrances that we naturally associate with warm, brown colours anyway: creme brûlée, chocolate, and anything vanilla or custard-like.

Check out this cool Pumpkin Spice Soap, which uses the fragrance to enhance its design.

If you absolutely do not want your soap to discolour in any way, I suggest you choose a water white fragrance – fragrances that are clear in colour, contain no vanillin, and do not cause discolouration. More about this next week!