The Greatest Secrets in Perfumery
| "The perfumer sits at his desk formulating a perfume. He has a list of 70 aroma chemicals, essential oils and bases in the formulation before him. He reduces the Benzyl Acetate and increases the Hexyl Cinnamic Aldehyde, he moves down the page where he adds a little Ylang Ylang Oil Extra, no..., pauses, his nostrils flare ever so slightly, as if mentally sniffing, now he changes it to Ylang Ylang Oil No.2." |
What is happening here?
Is the perfumer really juggling all those 70 items in his head, well perhaps, but more likely what he is doing, sometimes without realizing, is juggling accords. If we look at a formula of 70 items then the calculations of smell and interactions becomes extremely complex. If we think of the perfume instead as blocks, blocks of jasmin, blocks of rose, blocks of citrus, blocks of fresh notes, blocks of bottom notes, etc. then we greatly simplify the process. Perhaps in our example our perfumer was mentally examining the jasmin accord within the fragrance, maybe deciding that the jasmin character was too chemical or fruity, for this reason reducing the Benzyl Acetate and increasing the softer Hexyl Cinnamic Aldehyde, then adding the Ylang Ylang to give a richer natural note but choosing, in the end, the No.2 Oil
, as the fresher top notes of the Extra Oil were unnecessary.
| Are you ready for the greatest secret of perfumery ? |
| Accord. An Accord is the perfumery equivalent of a Chord in music. A blend of 2 or more smells that produces a 3rd different and distinctive smell. An Accord may be a simple mixture as already suggested or may consist of many materials. It particularly applies to where each component material is in balance and harmony with each other material so that no one single component can be detected. An accord is usually a small part of a perfumes structure just as a Chord in music acts as a single note in a symphony. |
Yes, Accords are the greatest secrets of perfume - sometimes they form only 1 or 2% of a formulation, but if well done, transform a dull lifeless fragrance into a masterpiece!. Despite the fact that accords in most reference works only receive cursory explanations they are the cornerstones of perfumery. Modern analytical techniques can frequently identify over 95% of a perfume formulation in chemical terms. Despite the accuracy of the equipment, when the components are compounded there is often a lot lacking - this is frequently because the keystones of the fragrance lie in traces of components that form part of accords within a fragrance. Frequently labeled 'sub-compounds' this is not a fair description of a true accord and a sub-compound may itself actually contain an accord. It is very likely that the perfumer during his experience has noted that certain combinations have a synergy. That is that the sum effect of the components is more than simply adding the effect of each single component together. A reason why in many companies a perfumer is advised "to compound
" himself is that the very act of adding material by material often leads to surprise discoveries of new accords to try out.
So lets think about how does one go about making an accord.
- The traditional way to develop an accord is to select two materials then mix them 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1. One smells each sample and selects the one in which both materials are in equilibrium, neither dominates, modifying slightly if necessary. Then we add a third material to this selected mixture 1:9, 2:8 etc. This technique is useful but in practice becomes hard to balance as the 3rd material upsets the first 2 in the mixture. The combinations with just 3 becomes quite complex and rises exponentially from there as we add 4th and 5th.
- How do we know what materials are likely to make good accords? Clearly we may come across them by chance, we make a compound and note that it's odor, diffusiveness or lasting properties are better than we had anticipated. We can then work back through the formula, material by material and try the combinations we think are responsible. Using the quantities in the original formula.
- A more systematic way that identifies the essential components of an accord found this way is to reformulate, taking one material out at a time until the effect disappears the last material taken out is clearly part of the accord. We replace it in the formula and continue removing the remainder of the materials one by one until the effect disappears again. We have now identified material number 2, we replace this in the formulation and repeat until we have removed all the parts of the formula that are not part of the accord. The accord we are left with can be further refined by experimentally adjusting the proportions of each component of the accord until the optimum is found.
- You may or may not be familiar with the term odor threshold, that is the concentration at which a material is detectable by its odor. The odor threshold depends very largely on the medium in which it is tested. i.e. the odor threshold of a non-polar material in a watery medium (insoluble in water) will be much lower (i.e. stronger) than a polar (water soluble) material The soluble materials molecules do not release from the water so readily. The opposite effect is found in an oily medium. Now if we use an aroma raw material as the medium and add a second aroma raw material slowly until the point at which we can detect i.e. its threshold in material 1, interesting effects are likely to occur around the threshold level. Then as the level is increased beyond this then a second point will be reached where the two materials reach equilibrium, no one odor dominates. By then using the 2nd aroma raw material as the medium and adding the 1st material we can record a second set of data. Is the point of equilibrium the same ?
- Another way is to consider the relative impact of materials. If Linalool is allocated an arbitrary value of 100 then Aldehyde C11 Undecylenic a relative impact value of 750, 7.5 times as strong then the accord level is likely to be around 1 parts (100/100) of Linalool and 0.13 parts (100/750) of Aldehyde C11 Undecylenic. If the accord was with a lower impact material such as Hydroxycitronellal (Impact 25) then the accord levels are likely to be around Linalool 1 part (100/100) : Hydroxycitronellal 4 parts (100/25). So How about an accord between the three materials - Linalool 1 : Aldehyde C11 Undecylenic 0.13 : Hydroxycitronellal 4. Remember these are only guidelines and factors such as polarity and volatility come into play.
| When choosing a raw material as the medium, (the first material) for an accord it is best to choose the material with the longer blotter life. Why ? |