Updated: Apr 4, 2018
Same as the first part, if you are thinking about getting into perfumery and/or you are just starting out, probably these series of articles are for you. Whether as a hobby or with the goal of making it as a professional I will try to give you all those pieces of information that I didn’t get at the beginning and that I think would have saved me a lot of time, headaches, and money.
This is the second part of an article started here. We already covered the starting point, the materials that you will probably need, how to storage them and how to make dilutions. Let’s keep going.
The “parts” of a perfume:
“In the nineteenth century, a perfumer named Charles Piesse invented a fragrance classification system in which each fragrance was matched to a musical note, and a successful perfume was one in which the fragrances blended into a harmonious chord. Piesse’s system did not catch on, but another perfumer named William Poucher used it as a starting point to create a classification system that has been adopted for perfumers and aromatherapists. Poucher proposed that fragrances be classified in three categories: Top (or head), Middle (or heart) and Base”. 
Usually, this classification is represented by a triangle (or pyramid) divided into 3 parts as shown in the figure.
When it comes to creating a perfume, we now know that the perfume will be somehow “divided” in top, middle and base notes. Why this division and how do we know which products are top, which middle and which base? Well, here is where things start getting interesting. We will add a “layer” of analysis to this basic categorization. Like an onion. This new layer will take into account how long a note (odor, aroma or smell) lasts over time. So, soon we realize that the first impression, whatever we smell first, the smell that introduces us the perfume (aka. top notes), rapidly disappear to let other notes appear in their place. These new notes, the middle notes, are the main theme of the perfume, its core or main character. They last a little bit longer than the top but eventually they submit to the last set, the base notes, which love to linger for undefined periods of time in the background. Sometimes referred to as the “dry down” of the perfume.
Try to experiment yourself with different essential oils and/or aroma chemicals by timing them up to the point of “no more smell”. Be aware that the smell will last more or less depending on whether you apply the material on paper or on skin respectively. Write down your results and have fun. The more you get to know your materials and how they behave over time the more you will know and the easier will be when you start mixing for real.
Why some odors last more than others? The answer is simple: Evaporation.
This variable is directly proportional to the size of the molecules of the material. At a chemical level, the bigger the molecule of the product, the more it takes to evaporate.
All this confirms that a perfume has a dynamic flow and that its smell changes over time. In addition, due to the fact that every material has a different evaporation rate, the transition from top to middle and from middle to base is not a sudden or abrupt change but a slow and multifaceted transformation.
So, it is not only how different materials appear and disappear over the time line but also how they interact between them as they appear and disappear! Over time, each material combines with the others in a specific proportion, creating a unique scent that is exclusive of those materials in those proportions on that certain moment of time. If you could take pictures of the mix of smells in those moments you would see that all of them are different.
And what about the proportions? Which percentage of top, middle and base notes we want our perfume creation to have? Well, the bad news is that there’s no rule, just some random values as guidance that can be changed to absolutely any degree. The good news: you can do it however you want! It’s called creativity! Some people say 33% of each, others 20%-50%-30%...you will find as many “guides” as people writing them. There is no one truth about this. It is your creation, hence you will decide how much it will last each of its parts and how they will interact between each other.
But now I got greedy, and I want MORE (I knew this was going to happen!). Let’s add ANOTHER layer to the pyramid:
Over time, there have been hundreds of attempts to create a classifying system of odors. Every single one of them had something lacking (Rimmel’s, Crocker-Henderson, Bain’s, Jaubert’s, Tapiero’s & Dore’s and a LOT more). This is why, still today, there is not an “official” way to “name” odors. For example, our visual system has a scientific explanation of what we see and how we see it, basically using physics to explain how light affects matter. This way, even though it’s proven that colors do not exist per se, we have a universal understanding of what “black” is, or “red”, or “blue” (not its meaning, but what they “look like” in reality). Now can we say the same about odors? An “earthy” smell, is exactly what? A citrusy one? Even when we transfer words from the flavoring field, the categorization is not universal. How does something sweet smell? And what about something acrid? All of this is because there’s no classification system that has EVERYTHING a classification system needs in order to be useful and universal 
Have clear classes that single materials can easily fit.
Cover all combinations of smells, preferably for a wider range of smells than for just perfume or flavors.
Be the basis for describing any odor.
Recognize that an odorous substance, molecule or product may have more than one facet to its smell. E.g. the smell of chocolate is sweet, creamy AND balsamic.
Have some factor that incorporates the pungency or strength of an odor.
Have a time factor for how long the smell lasts.
Be easy to learn.
I told you I studied with PerfumersWorld's system and that they have something called the ABC of perfumery. What is this? Basically is a categorization system that has all the 7 points just mentioned. Yes, each letter, from A to Z represents a category or “type” of smell. Its name coincides with its letter as well: the C is for "Citrus", the N for Narcotics, the P for “Phenols", the R for “Rose” and so on. One letter for one type of smell. 26 types of smells total.
Well, let’s try then to superimpose this ABC to our pyramid, shall we?
After carefully analyzing the graphic maybe you can start understanding why I think this ABC system is GENIUS? Those letters (or type of smells) not only follow the rigorous order of the ABC but ALSO the evaporation rate, from super volatile up to the most long lasting smells we can use in perfumery. EXACTLY! I take my hat off to the mind that came up with that! And then you have combinations of letters, and ways to measure the strength of the smell, etc., etc. Well, if you want to learn more about their system contact them (and tell Stephen Maximo sent you –wink, wink– lol).
Before getting into actually making a perfume, let me add one last thing: materials also have a “function” in a perfume:
Main or Heart:When you smell a perfume, you can always put a finger in a particular smell: that’s the heart! The one that without it, the perfume would just not be. Usually, coincides with the Middle notes.
Modifiers: They literally modify the basic materials, giving them a chance to show a different aspect or facet by adding a “decorative touch”, a uniqueness. Use these sparingly. If you can actually smell the modifier in the mix, you’ve probably overdone it.
Blenders: Heart and Modifiers are sometimes REALLY different (think of oil and vinegar), Blenders are the ones in charge to make them get along fine. They smooth the differences out. They round up the composition.
Fixatives: Usually Base notes, they provide depth and substance. They can also slow down the evaporation rate of other materials. Some fixative essential oils to play with: Ambrette seed, Amyris, Angelica root, Peru Balsam, Labdanum, Clary Sage, Frankincense, Galbanum, Styrax, Myrrh, Oakmoss, Orris root, Patchouli, Sandalwood, Vanilla, Vetiver and Violet leaf.
OK, I think we are ready for our first mix:
Let’s roll up our sleeves!
There are several mixing theories to make a perfume. Some people say you should go by function: Heart first, then modify, then blend and finally fix. Other people say to start from the end: working the Base notes first, then the heart and then the top (supposedly this way you can smell the perfume backwards: you start working/smelling only the “dry down”, then you add the heart and then you add the top notes, so literally as soon as you are finished, you are smelling the opening of the perfume). Other people suggest to mix the different parts (top, middle, and base) separately and then work your way with proportions of these parts to obtain a final mix. As you can see there are a lot of ways and none of them are wrong neither right. There is actually only one correct way to mix a perfume: YOURS, the one you feel comfortable with. We are talking about a creative process if someone tells you “It HAS to be done this way” I would start walking the opposite way from that person. You do not need people like that in your life. A creative process should not be regulated. I can tell you what works for me but that should be the extent of it. It is NOT the TRUTH. It’s just my way.
I personally tend to use the first two ways I described, mostly the first one. But remember: try everything, maybe you can start by doing a mix of top and base and to that you start adding heart notes till you find an equilibrium in your composition. Who knows? I cannot stress this enough. There is NOT just one way of doing things (and remember these words for when I drop the bomb that I experiment in drops and not in grams…but don’t worry, that’s going to be another whole can of worms, eh... blog post).
So, for t