I tend to repeat myself when I say that perfumery can be confusing, so please just humor me.  In part, I think it is my trying to let you know that if perfumery is at times confusing to you, you’re not alone.  Not by far!   

There are various reasons why perfumery can be confusing.  For one thing, when working with perfumery we’re also dealing with chemistry.  For some people, chemistry is something they flow to like fish to water.  For the rest of us, it is a borderline incomprehensible science. I am an artist by profession — and internal wiring.  Often, artists and sciences such as math, physics and chemistry, do not go well together (yeah, I know, music is mathematic and all that, but still).  This may explain why most of us professional artists also need managers, promoters and accountants!  When I approached perfumery, I did so from an artist’s perspective, not as a chemist.  Regardless, I could not ignore the fact that I was working with molecules.  Hate chemistry or not, one cannot avoid feeling like there is indeed something fascinating in all of this.  A chemical like Phenylethyl Alcohol smells faintly like roses because roses contain this chemical in their scent molecules.  Then, when you mix this chemical with another chemical, those molecules combine to change the characteristics of both chemicals and form a new one, and a different scent.  When you mix a bunch of scent molecules, you have a perfume base.  In Aromatherapy, this is called ‘synergy.’   When you mix that perfume base into perfumer’s alcohol, more molecular changes take place and your perfume matures to potentially become exquisite.

Here is an interesting chart of some molecules found in the scent of well-known flowers.

Image courtesy Compoundchem.com

The above molecular talk can be easily grasped by most, even if one is not a chemist.  I do not want to be one; it is not in my nature.   The good news is that, regardless of the opinion of some, one can still practice perfumery without having a degree in chemistry.  If you’re chemistry inclined, however, things are a little easier for you.  For the rest of us, it is just more work – but still much enjoyable.

What about dilution?  

You may be wondering at this point where I am going with all of this, and the answer is: Dilution.  Dilution has almost become controversy in non-professional perfumery forums.  And here is yet one more reason why perfumery can be confusing, especially when starting out. I admit, I almost fell for the dilution ideology myself, but I am too practical and early on I realized this was just not going to work for me.  

Is there a merit to diluting your aromatic ingredients? Yes. Do you have to? No.  And that is an emphatic ‘no.’ There is a catch, however, but I’ll get to that.

I could keep this short and just end the post here.  However, I would like to go on and explain some things regarding dilution, such as why some feel it is imperative, some do not, and where there is a middle-ground to be found.  

Something you no doubt have come across in on-line perfumery journals, or in one perfumery forum or another, is the ideology that learning has to be done by diluting all your materials to 50%, 10% or 1%.  I call it ‘ideology’ because for some of these people there is simply no other accepted way. Some push this idea fervently, as if you could not possibly practice perfumery successfully otherwise.  This is a practice somewhat perpetrated by perfumery houses who train their students using dilutions.  Don’t get me wrong, it works…but much easier if you are a multimillion-dollar perfumery house with a lot of material you can afford to waste. In a way, for these companies it is not waste, because there is a lot of money to be made in training their future perfumers.  As with most businesses, some waste is expected. And it can even be expensed!  Never mind that many of these materials are produced BY these same perfumery houses (i.e. Givaudan, Firmenich, IFF, Robertet, etc.).

Dilution = Money!

The scent of an aroma-chemical does indeed change upon dilution, which explains why this method can indeed work.  Also, because many aroma-chemicals are strong, dilution is kinder to your sense of smell and sinuses in general.  But when you have to be realistic, practical and weigh your pros and cons, dilution as a hobbyist or niche perfumer becomes difficult to justify.  Generally speaking, most people studying perfumery on their own are not a perfumery business. At least not at first. Some will eventually go in that direction (welcome to the regulation headache), most will not.  Therefore, most people do not have extensive amounts of money to waste on product. Let’s face it, perfumery is not cheap!  Diluting, then, becomes a prohibitive practice.  Dilution equals money. Not to mention it is not really necessary for the most part.  There is already waste when you have to create various iterations of a formula to reach your desired fragrance, discarding previous formulations.  So then, we opt for method B, which also works.  

Early on, when I came into perfumery after years of working with Aromatherapy, I read as much as I could and I would go into all the available forums and try and absorb it all.  I would get whatever books I could, and read more while doing much hands-on experience.   But initially, things were getting confusing because everyone had a different opinion on how to do things, and worse, one comes to find out that some people who claim to know a lot really have no clue and are learning just like the rest of us.  They really do not know more, but are able to come across like they’re experts, and because we’re new to this we’re likely to believe them and take these people at face value.  When it comes to perfumery practice, blind following might cost you dearly. Keep in mind the cost of the product you’re diluting, the dilution agent you’re using to dilute it in (i.e. DPG) and the container (glass jars). Multiply that for each and every single perfumery material you have and I don’t think I have to say much more.

Still, I love experimenting and so, early on, I followed this one hobbyist who kindly posted his formulas on-line.  He seemed to know what he was doing, so why not try what he offered?  This guy had people diluting oils and aroma-chemicals into percentages I had not seen anyone else using, which struck me as odd.  But, alas, I followed a few of his formulas. In the end, I was not impressed with the perfume results of his formulas and quickly moved on.  But now I was stuck with a few oils and aroma-chemicals diluted at percentages (like 35%) which made them useless for any other use. Thankfully, I had not wasted much material, but I realized something was not right for me.

Meanwhile, others claimed one had to dilute every single oil and aroma-chemical into 50%, 10% or 1% dilutions to learn how to work with them.  This seemed impractical.  It is amazing to me that I had such insight early on (call it intuition), which eventually saved me a lot of hassle, money and materials!  As I grew in the practice and learned to work with hundreds of materials, I stopped one day and said aloud to myself, “I am so glad that I never diluted this!”  The aroma-chemical in question was Phenylethyl Alcohol.   After all these years, I have yet to use it diluted.

Like Phenylethyl Alcohol (also known as Phenyl Ethyl Alcohol or simply PEA), there are many aroma-chemicals that do not need to be diluted to work with.  In a recent post of mine in which I wrote about working with solid aroma-chemicals, I mentioned that even most solids do not need to be diluted to add them to your formula, unless you expressly want to.  This is where chemistry comes to play.  Most solids will dissolve when mixed with other aroma-chemicals and essential oils. In fact, many materials you can purchase diluted are diluted using other materials like Benzyl Benzoate, a useful, slightly Balsamic aroma-chemical in its own right.


Materials which come as solids or crystalline powder were originally a head scratcher for me.  Some people would say, “Dilute your Veratraldehyde at 50%,” but then a formula asked for Veratraldehyde at 100%.  Uh…what?  If I was diluting everything and then needed something at 100%, how was that going to work?  If a formula did not expressly ask for an ingredient to be used at a specific dilution rate, it was to be used at 100%.  I decided there was something amiss going on and the whole dilution thing was not working for me.  Sure, I could double the amount I had at 50%, but I still felt like I should be using it at 100% when so stated.  But if I did not dissolve and dilute the solids, how could they work in a formula?  I solved this problem on my own, by experiencing working with real formulas.

In many of my other posts, especially in the pages on getting set up and creating, I mention a book by Louis Appell.  I recommend his book because it is a treasure trove of vintage formulas, which can be extremely useful for hands-on learning.  In following his formulas, I found that he would often ask for solid or crystalline materials like Vanillin or Coumarin used at 100%. So, I jumped in and followed along. Lo and behold the crystals and solids dissolved, often immediately, into the jar containing other oils and aroma-chemicals I was mixing.  This happened each and every time.  It never failed, no matter what solid I was working with.  

A chemist may stare at me and say, “Well, of course. It is simple chemistry!” and a professional perfumer may scoff and think, “Really, Sherlock?”  But when you are just getting started, all of this perfumery business is like learning a whole new language, and the most minute detail seems like a complex enormity. In figuring this out, I almost felt like I had conquered some kind of mountain and needed a flag to plant on it and commemorate the moment! And I wondered…why was no one mentioning this in the forums?!

Dilute…when you must.

By now I figure I have made my point as to why one does not need to dilute materials to use them or learn to work with them.  But here is the catch: this does not mean you will never need to dilute materials.  You will indeed need to dilute some of your materials, but you will do so for a whole different reason — their scent strength, ease of use and cost.

Let’s address using dilution for ease of use.  I will use Galaxolide as an example. Galaxolide, a Musk, is very viscous and difficult to pour at 100%. Forget using a pipette!  I have some diluted to 50% in alcohol, but also work with it at 100% for when I want/need to use it at full strength.  When at full strength, I use the hot water method to heat it up and make it flow easier. Some essential oils, especially absolutes, can be extremely viscous as well. Tobacco Absolute and Oakmoss, for example, need to be diluted to be workable. Some of these materials one dilutes at 10%, while others can also be diluted at 50%. Oakmoss, for example, can be used at 10%, 50% and 100%, depending on need. Some will become pourable when heated, some will not.

Now, let’s address using dilution to minimize scent strength.  Some aroma-chemicals, like Aldheydes*, are extremely strong in scent and need to be diluted before you use them, otherwise you can kiss your formula goodbye with a mere trace of an undiluted Aldehyde.  Granted, there are rare occasions where you would use an Aldehyde at full strength.  Some materials, however, you will never use 100%.  In the The Good Scents Company data website, these materials usually carry a ‘High’ label next to scent strength.  Some materials like Geosmin are so incredibly strong, that even at 1% dilution, and only in trace amounts, they can ruin your formula.  Some sellers will not even sell some of these materials at 100%.

*As an added statement, I want to mention the Aldehyde confusion. Aldehydes such as C-9, C-10, C-11 and C-12 are ‘real’ Aldehydes, while Aldehydes such as C-14 and C-18 are not, even though they are called as such. The so-called Aldehydes do not oxidize as the real ones do. This is definitely a subject for a larger post, but it required mentioning.

Like Aldehydes, I find some materials particularly in the GREEN and ANIMALIC families to generally need dilution. Certainly not all, but many do.  Cis-3-hexenol is a material in the GREEN family which is often used diluted, and having a 10% dilution ready is always a good idea.  Same goes for ANIMALIC materials like Civet, generally used at 10% and 50%.  Oakmoss is another material most often used in diluted form, as I previously mentioned. Keep in mind many strong materials are generally used to add interest, hints and shades to your perfume, not to make a big splash. In diluting these materials, it makes it much easier to add trace amounts of these to your formula.

If there are a some materials which you really feel like you need to learn more about to figure out how they smell, by all means you can dilute those to test them out. It is definitely not going to set you back financially, and you’re not really wasting much product.  Materials like Ionones, Hedione, Benzyl Salicylate, are difficult materials to assess.  Ionones in particular can cause olfactory fatigue faster than you can blink!  Diluting these and sampling them during a few days time can better help you ascertain how they smell and what they can contribute to a formula.  

But do keep in mind that, as with all aroma-chemicals, once these interact with other molecules in a formula, their scent will change, so even an individual dilution test will not necessarily give you all you need to know about a specific material.  Only experience will give you a better idea as to what these materials can really do in a formula. And even then, some still find Ionones and other aroma-chemicals like Hedione perplexing, even after working with them for years.

1+1 = Two Of One.

Something important to consider is that, when diluting your material, you’re adding another material to the mix.  I prefer to let a dilution sit for a few weeks before I use it, so it fully mixes together with the dilution base material, whether it be alcohol, DPG, Benzyl Benzoate, etc.  Also, you want to consider that when you dilute your material, you’re also adding the secondary material to your formula.  While these two materials become one, they double the space. You need to consider this for two reasons.  Weight and scent.

Let’s discuss the weight problem.  Using weight, let’s say you want to add 1.000 grams of Cinnamic Alcohol to your formula, and you happen to have it diluted (easier to use) at 50%.  That means that your 1.000 gr of the dilution will only contain 0.500 gr of Cinnamic Alcohol, and 0.500 of whatever your dilutant base is.  This then means that you will have to add 2.000 gr of the dilution to your formula to get the 100% amount of Cinnamic Alcohol you desire. But you’re also getting 1.000 of your dilutant.  See where I am going with this?  The solvent material takes a lot of space that can be used for other materials.  I then rather not waste the space if I have other materials that may need it. I then prefer to heat my Cinnamic Alcohol to liquify it and use it at 100%.  If your formula only has ten materials, it is not a big deal if you need a larger quantity of material and it is diluted at 50%. If, however, your formula has 35 materials, including bases, you’ll run out of space, wight-wise as your scent real estate has gotten tighter.

Now, let’s discuss the scent issue with dilution.  The problem here is that sometimes you may use another aroma-chemical, like Benzyl Benzoate, to dilute your material.  In this case, you’re adding your material AND Benzyl Benzoate to your mix. While extremely light in scent, Benzyl Benzoate does have its own scent and it may affect your formula.  This is why some prefer DPG, alcohol, IPM, etc. for dilutants, but not all materials will dilute in all of these.

Keeping the above in mind, this is why I avoid diluting my materials unless I really, REALLY, have to.  When I do, I take the dilutants into consideration and label them accordingly, so I know what the material is diluted in.  My label may read something like this: Cinnamic Alcohol 50% DPG. If you used a material in your formula diluted, you want to use it again at a later date for that same formula diluted in the same dilutant. If my Cinnamic Alcohol was diluted in DPG when I used it in the formula, when I recreate the formula the Cinnamic Alcohol I use has to be diluted in DPG again. Diluting it in something else will change scent and weight, which will modify my formula, something I do not want.

When you’re diluting a material due to its scent strength, weight/space in your formula is not as much a problem because even in diluted form, you’ll use very little of these materials.  Cis-3 Hexenol, for example, diluted at 10% may take only .100 or less in your 10.000 (10) gr. formula. A material like Isobutyl Quinoline, you’ll use a trace of it even at 0.01% dilution.  Not much space to really be concerned with.  Materials like Piperonal (Heliotropin) or Cinnamic Alcohol, however, you may use quite a larger amount in your formula, and if these are diluted, they can take up precious space.

Green Irish Tweed by Creed

Cost effective

One other reason to dilute your materials is to make them cost effective. This is something one mostly does with Essential Oils. Oils like Broom (genet) Absolute are very expensive. However, if you dilute a small amount to 10% in Perfumer’s Alcohol, you extend your oil quantity. Some oils, like Cascarilla, will add quite a presence in your formula (think of the perfume Green Irish Tweed, to which a trace of Cascarilla oil adds just a hint of lovely woodsy spiciness). Cascarilla can be expensive, but at 10% and used in traces, you can add dimension to your perfume. The same goes for Jasmine Absolute, Rose Absolute, Orange Blossom Absolute and other oils which can be costly, and yet at 10% can be added to your formula to add naturalness while being extended with aroma-chemicals…and without setting you back financially.

So, in the end…

To sum it all up, I never dilute any of my materials unless I need to for ease of use, scent strength or cost effectiveness.  This means I currently have diluted on my shelves (or refrigerator), about 10% of all my materials.

Always keep a good stock ready of the materials that you do choose to dilute.  They need to mature (blend well with the dilutant), and making the dilution five minutes before you put your formula together is not really a good idea.  Same goes, by the way, for perfume bases or accords.  They need time to mature before they can be used in a formula or final alcohol dilution (see my post on this).  Look through your shelves every so often to see what dilutions or accords you may be low on, and make more.  Or, when you are putting a formula together and notice that you are low on something in dilution, make a note to make more so you can have that prepared and matured by the time you need more. Never wait until the last moment; perfumery is not a by-the-seat-of-your-pants practice. One plans ahead. Always.

Think of it as a party you throw with 50 people attending, where not everyone knows each other.  You need time to let people arrive, meet and mingle before they get comfortable together. Some people will jump in right away, while others (us introverts) will need time to adjust and feel-out the room.  Only about an hour in will most people feel at ease.  Aroma-chemicals and essential oils are no different.

As with all things, one learns as one goes along.  The more familiar you are with perfumery materials, the more it will all become second nature to you as to which materials are strong and need dilution, and which ones are fine to use at 100%.  You will also learn their strength in a formula and will eventually know quite easily how much you need of what to create the effect you want.  Nothing is written in stone, however, and sometimes you may ‘overdose’ a material which otherwise you’d consider strong, to create a desired effect in a formula.

If you begin your learning by practicing on formulas like those found on the book by Louis Appell, there will come a point where you will have amassed quite a generous amount of materials, and will also have diluted what you need to and have it for future use.  You will also have created many perfume bases/accords to have handy.  I cannot stress enough how learning from his book and following his formulas can be of extreme help.  It may take you a couple of years to get through his formulas of perfumes and bases, but at the end you will look back with greater knowledge, more confidence and a healthy perfumer’s palette.  Because his formulas are vintage, after this period of learning you will want to start moving forward by learning to create modern perfumes, which use materials Appell did not, such as Hedione.  

Hopefully, this post will help straighten up the confusion and myth about dilution, and you can better see what works for you.

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