Why does the scent fade in my soap? How do I get essential oils to 'stick' in my soap?

These 2 questions crop up without fail pretty much every week in the soap making forums and for good reason. It is a problem.

If you know anything about me at all you will know that I only use essential oils in my soap making. I have nothing against artificial fragrances, it just was not the direction I wanted to take in my business which is all about keeping my soap as natural as possible and teaching others the same. I generally only use natural colourants, for the same reason.

That said, using essential oils in soap making is not the easy option. The high PH in soap can destroy some scents and scent can also to fade over time. There are ways and means of trying to get your scent to stick in your soap, but ultimately it is very much a case of trial and error and what works for you.

This is the one subject that arises time and time again amongst soap makers and is probably the biggest issue we face.

With that in mind, I have put everything I have learnt so far in this blog. It includes which essential oils last the longest in your handmade soap, the best ways to blend essential oils for soap making and hints on tips on how to get your scent to 'stick'

This is not the definitive 'right way', just 'my way' and what I have learnt in my soap making journey.

What is meant by 'notes' in essential oils?

In a nutshell, essential oils are split in to 3 'notes' top, middle and base. Some cross over 2 of those notes.

Top notes are lighter and tend to be those you smell first in a blend. Citrus scents are a good example of a top note, light and fresh. Top notes disappear quickly - this goes for scent in a perfume as well as in soap although there are exceptions such as peppermint.

Middle notes are a little heavier, they can be floral , woody, spicy or on occasions citrus. They tend to hang around a little longer than top notes. Lemongrass, geranium, lavender, rosemary are all examples of mid notes. 

Base notes are much heavier, tend to be woody or spicy but can include floral such as Ylang Ylang. These tend to be the longest lasting and can work very well in soap making especially when combined with some of the lighter notes.

How should I blend essential oils for soap making?

I have found that combinations of at least 3 essential oils generally tend to do better in soap than single fragrances. I have 2 blends that contain 5 essential oils and these are my longest lasting fragrances.

There is also the view that some scents can be used to anchor others. for eg if you want a lemon scent do not use just lemon, try lemongrass and may chang, both of which have a citrus scent but are much longer lasting as they are mid notes. Some such as peppermint are extremely strong and although a top note itself can overwhelm other scents very easily so go easy on that one.

Do consider using a range of notes in your blend, additionally do not hesitate to use 4 or 5 different essential oils, it can often make a huge difference to your overall scent.

Go easier on the base notes if you are using as part of a blend. Start with a simple combination 1 part top, 1 part middle, 1 part base as an example.

If using a mid and a base note then try a 50/50 mix.

It is perfectly ok to just use a mid or a base note on it's own but this won't work with a top note in my experience.

Unfortunately there is no cut and dried formula - every blend really does need to be calculated on it's own merits but all is not lost, there are plenty of suggestions for blends online - just make sure the % are safe (see below).

I love woody, musky scents such as Patchouli and find it pairs beautifully with other scents such as sweet orange and really helps the orange scent hang on in there. Ylang Ylang is one of those scents I cannot bear in the bottle but it is incredibly versatile and long lasting in soap, use it with grapefruit and geranium for a beautiful long lasting scent just go easy on the Ylang as it will over power.  2 parts grapefruit to 3 parts geranium and 1 part ylang ylang is a good start but you can tweak to suit your individual preferences..

Tea tree and eucalyptus do well, lavender is not my favourite scent but I love it in so many different soap combinations, it is long lasting, blends with numerous other oils and is cheap compared with many. Do not be put off by the association of it appearing old fashioned, if in doubt try a lavender/peppermint mix and see what you think.

Lemongrass, may chang and neroli are all good for a citrus blast, whilst I love grapefruit it is not good in soap, the scent is here today and gone tomorrow so you really need to pair it with something to anchor that scent right down, Ylang and geranium as above is good, or try Patchouli. I love it so much I refuse to give up on Grapefruit completely.

Rosemary is another all time favourite, it is incredibly versatile, has a distinctive scent, lasts well and is economical.

When deciding on your combinations you must bear in mind that firstly there are max permitted % allowed in soap (3% in the UK/EU as a guide) but also that different essential oils have different limits themselves. Some can only be used in very small amounts. Unfortunately this information is not readily available as it is also determined by combinations and total allergens in those combinations.

What can I use to anchor scent in my soap?

Anchoring your scent - the single biggest headache I can think of in soap making. There is a school of thought that mixing your essential oils with natural clays prior to adding to your soap mix gives it something to 'stick' to. Kaolin clay is a big favourite and this is something I feel I have had some success with in recent batches. I have also used my coloured clays, green clay or pink clay for example and I have come to the conclusion that they work equally as well. Mix your clay and essential oils together before you add to your soap batter and just let them sit for a few minutes.

Some soap makers like to soap at cooler temperatures and feel this is helpful. If you are making hot process soap then do not add your essential oils until after your soap is 'cooked' and even then make sure your soap batter is below 180

degrees fahrenheit to reduce evaporation before you add your scent.

Your choice of essential oils will have the single biggest impact on the final result.

Without a doubt however, the single element which will impact the most on your final scent and the longevity, is the essential oils you use. Try and go for those which are known to pull through the process, blend well with the others you have chosen, and if they smell strong and possibly even overpowering in the bottle there is a good chance they will do well in your soap. Experiment and have fun! There are no rules, sometimes the most unusual combinations work the best.

Need some help with blends?

Grab my 101 Essential Oil Blends That Last eBook for more information and some inspiring blends.