I get a lot of questions around the topic of how to dilute materials before use when making perfume and it came up again in the class I did last weekend so I thought I’d dedicate this weeks blog post to the topic.
Why Dilute Perfume Materials and Essential Oils?
1. Many materials are difficult to work with in their raw state
The materials we use in perfumery come in many forms and consistencies and many are difficult to work with in their neat state. Essential oils are mostly fairly mobile, easy to measure out and blend with each other. Absolutes and resins can be sticky, solid and almost impossible to measure accurately in small amounts. Diluting before blending makes things a whole lot easier.
2. Sometimes we want to use tiny amounts of something in a formula
When experimenting with a new formula and using expensive materials we do not want to make up a large batch just to add a tiny amount of a really strong material. Diluting enables trace amounts to be added and prevents wastage if the formula doesn’t go to plan.
3. Materials are often easier to smell in dilution
When we smell, we are smelling the air above the material as it evaporates (the headspace) not the material itself. When we dilute in alcohol it helps the material to evaporate and we get a fuller profile of the scent. Some materials are easier to smell in dilution than neat.
What To Dilute Perfume Materials In
Firstly I’ll start by saying that diluting in a carrier oil is fine for aromatherapy and massage but not really for perfumery unless you are just making an oil based fragrance. A carrier oil will not give you the full profile of the material for evaluation purposes as it doesn’t aid evaporation.
1. Perfumers Alcohol
If you are making an alcohol based perfume spray then it makes sense to dilute your materials also in perfumers alcohol. If you do this then you will not be able to add these dilutions to bases such as candles, creams, detergents or oils. Perfumers alcohol is also good for evaluating the odour profile of your materials when training your nose.
Di Propylene Glycol is a solvent commonly used in the fragrance industry to dilute otherwise insoluble materials – this is more commonly used than perfumers alcohol due to the fact you can use it in bases other than alcoholic fragrance. DPG is petrochemical derived and therefore not really suitable for natural perfumery.
3. Other perfumery Materials
Benzyl benzoate and Benzyl alcohol are sometimes used in fragrance compounds to aid the blending of hard to work with materials, again they are aromachemicals which restricts their use for the natural perfumer. If you are creating a fragrance blend with naturals and do not want to use any of the materials suggested above then you will need to compound your fragrance neat. It it best to start with the more robust materials that need to be heated and add the rest in order of volatility once you have removed from the heat.
How To Dilute Perfume Materials
1. Choose your %
I generally stick to 10% for most materials with the exception of things like Ethyl Vanillin, Calone, Violet Leaf etc where 1% is more than enough. Use your own judgement but the more you dilute the smaller amount of material you can add to your formula when you are making up in tiny quantities.
2. Always use a scale
I say this time and time again in my classes – do NOT use drops!
Always use a scale when diluting or blending as this is the only way you will get an accurate and repeatable formula. If you are doing this professionally you will want to invest in a proper lab balance but for beginners and hobbyists a jewellery scale (from ebay for less than £10) is a good start. Choose one that goes down to at least 0.01g and measure into either a washable glass beaker or directly into a dropper bottle. For 10g of material at 10% you will need 1g of the material and 9g of the diluant (alcohol or dpg). For 10g at 1% you will need 0.1g material and 9.9g of the diluant.
3. Heat thick materials gently
Some materials will not dilute easily unless you warm slightly to mobilise. I use a water bath (a beaker with hot water) and stand the bottle of material in until it liquefies. Sometimes you need a bit more heat and I have an electric leg wax melter for this purpose. With materials such as Tonka Absolute and mimosa absolute you will need to gently warm the absolute in a water bath, blend with alcohol and then return the beaker to the water bath whilst stirring to get the absolute and alcohol to blend. Do this very carefully and only for as long as it takes to blend to minimise evaporation.
When Not to Dilute Perfume Materials
1. When making up a batch in cream, detergent, candle, soap etc
If you are diluting in perfumers alcohol then you will not be able to add these materials to certain bases – keep the dilutions for experimentation, evaluation and making alcohol based fragrances only. For other bases either use dilutions in DPG or use neat.
2. Don’t dilute all your materials
Obviously you don’t want to dilute everything as you may need to keep some to use neat.