How to Dilute Perfume Materials

Ah, perfume making! It’s so romantic, so poetic…so FULL OF MATH.

Why dilute?
Perfumers often need to dilute their materials to 20%, 10%, or sometimes even 1% or .5% or more before adding them to a blend. This serves a number of purposes – from wasting less material while blending to making it easier to work with trace amounts of strong-smelling materials.

What material to use as a diluting agent?
Typically, you’ll want to dilute in perfumer’s alcohol. You should dilute in whatever medium you would be working in – so if you are making oil-based perfumes, dilute in oil. Some people prefer to dilute in Dipropylene Glycol (DPG), which is a common odorless solvent that is completely soluble in water, alcohol, and some oils – and it also is a humectant (attracts water) and has fixative properties. A strictly all-natural perfumer will not want to use DPG since it is a synthetic, but if you’re concerned about safety, don’t be. According to the Environmental Working Group, DPG is safe / very low risk.

Use Weight/Weight Dilutions
An important consideration is that when professionals are talking about dilutions in the perfume industry, they are talking about diluting by weight rather than by volume. So assume all dilutions on any materials you purchase or for any formulas are listed in weight/weight.

Creating a Dilution from Materials at 100% Concentration
Creating a dilution from 100% pure raw material is relatively straightforward.  In the chart below are the ratios in generic “parts” – this would work for drops, ml, grams, etc. as long as you keep the units of measure consistent – but as I mentioned, most professional perfumers work by weight (grams) – so let’s assume this is grams.

If you don’t want to do the math, here is a weight/weight dilution calculator.

You can also check out this nice tutorial on dilutions and blending from Chris of Pell Wall Perfumes. He gives a very thorough step-by-step approach.

Aroma Material Dilutant Total Parts Percent Dilution
1 1 2 50%
1 2 3 33%
1 3 4 25%
1 4 5 20%
1 9 10 10%
1 19 20 5%
1 99 100 1%
1 199 200 ½%

Creating a Dilution from Materials at Different Concentrations
What if you want to do something a little more complicated? For example, I have a bottle of Benzoin Absolute pre-diluted to 50%.  I have a perfume formula that calls for Benzoin at 20% dilution.  How do I dilute a 50% solution to 20%? (These are the questions that make former English majors clutch their heads in agony and wish they’d paid a little more attention in Chemistry lab.)

Well, it turns out there’s a relatively straightforward formula for this: C1V1=C2V2.  C=Concentration and V=Volume. Now, I don’t want to do this by volume – I want to do it by weight. If I wanted to be super accurate, I should probably take into account molecular weight. But since the amounts I’m dealing with are relatively low and I don’t need to be that insanely accurate, I’m not going to worry about molecular weight. (Also, if a chemistry person is reading this and wants to explain how to do this absolutely properly, I’m all ears! Please comment!)

Okay! So let’s figure this out. How do we dilute a 50% solution to a 20% solution? I’m about to do some math. If, like me, math makes your head hurt – you can skip the pain and go use this handy-dandy dilution calculator.

But hey, if you want to see how the math works, here goes. I already know my concentrations. All I have to decide is what final weight I’d like to end up with. For kicks, let’s decide on 5 grams final weight.  So!  Here’s how it would work out:

C1W1=C2W2

    • C1 = 50% = .5
    • W1 (the weight of the 50% solution to add) = unknown
    • C2 = 20% = .2
    • W2 = 5 grams

.5(W1)=.2*5g
.5(W1)=1g
W1=2g

So, okay – now I know that I need 2 grams of my starting 50% solution, and I want to end up with a final weight of 5 grams. So 5 grams – 2 grams = 3 grams. Which means I need to add 3 grams of my diluting agent (alcohol) to 2 grams of the 50% material to get 5 grams of 20% material. Or…

Starting % Ending % How many grams First solution? How many grams diluting agent to add? How many grams final solution?
50% 20% 2g 3g 5g

That’s it! Do you have a better method for calculating dilutions? If so, please comment! I’d love to hear from you.

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Supplies for Creating Perfume

Perfume Organ

Perfume Organ, Fragonard Perfume Museum, Paris by Nico Paix

Beginner’s Kits

Raw Materials – Naturals

  • Aftelier* – Quirky selection of unusual perfumers botanicals. Fast shipping. No minimum.
  • Aqua Oleum – Excellent UK source for essential oils from Julia Lawless.
  • Aromatics International – Expensive oils connected with the Aromahead Institute. Site has excellent information.
  • Eden Botanicals* – EOs, CO2s, Absolutes. Excellent quality, wide selection, no minimum purchase.
  • Enfleurage – Aromatics from the natural world. Specialize in Frankincense. Also offer hydrosols and more.
  • Liberty Natural Products* – Amazing selection. Includes isolates and more. $50 minimum.
  • Mountain Rose Herbs – Wide selection. Somewhat expensive shipping. (Mentioned more often by home aromatherapists than perfumers. Never tried.)
  • Nature’s Gift – Just tried them for the first time for more aromatherapy-type oils. Also have wide selection of hydrosols, carrier oils, waxes and butters. Well researched and reasonable prices.
  • White Lotus Aromatics* – Gorgeous, superior quality naturals personally sourced from around the world. $100 minimum.

*Companies with an astrix * are the ones I order from most frequently. Eden Botanicals is my “go to” supplier.
Also helpful: Providence Perfume offers a useful review of some of the best/worst essential oils she’s ever purchased.

Raw Materials – Synthetics

Beeswax

Carrier Oils
Carrier oils are for making oil-based perfumes, solid perfumes, or other body products. Do not add them to alcohol-based perfumes (they will separate and make a mess). Some carrier oils will go rancid fairly quickly. Fractionated coconut oil and Jojoba oil are two of the longest-lasting.

Alcohol
For alcohol-based perfume, use perfumer’s alcohol a.k.a specially denatured (SD) alcohol, which is 95% ethanol that has been denatured with an additive. The denaturing is done for regulatory reasons to prevent consumption. When purchasing perfumer’s alcohol in the United States, use 40b, which is denatured with t-butyl alcohol & Bitrex. Do not use 39c, because it contains diethyl phthalate (DEP), a.k.a. phthalates for which there are serious health concerns. For natural perfumers, there are also organic alcohols that have been denatured with natural materials. If you are not planning to sell your perfume, you can also use Everclear / Pure Grain Alcohol instead of Perfumer’s Alcohol. It should be 190 proof (95% alcohol) ethanol. In the USA, PGA is available for purchase in some states but not all. Some natural perfumers will also use Vodka for perfume, but it’s not as desirable as Everclear/PGA due to the lower alcohol content. For cleaning, you can use Isopropyl alcohol, Vodka, or PGA.

Dipropylene Glycol (DPG)
DPG is an odorless, colorless synthetic carrier oil that is perfect for diluting fragrances to 10% or 1% to be used for sniff tests / educating your nose. It is oil-based, but water and alcohol soluble.

Bottles and Packaging