Maturation issue?

AdamE

Super Member
Jul 15, 2019
I primarily work with all of my materials at 10% in ethanol.

When working on a blend Ive noticed that I can compose something, set it aside for a day, and then come back to it and it smells pretty much the way its going to smell within that time frame.

I will sometimes like what I smell, and set about to make a concentrate from the formula, using materials at 100%. Typically, I will combine those materials at their proper weights, often scaled up for batching, and will immediately add the ethanol , swish it all around to get the concentrated materials to go into solution, and then leave it on the shelf. after 24-48 hours, I sniff the batched bottle and immediately freak out that I have ruined something, or miscalculated some material, or added way too much cinnamon (most recent formula) because it smells NOTHING like what it did at 10% in the initial sketch.

I suspect this is a maturation issue? I need to be leaving these mixes to sit for weeks, especially if they're heavy with resins and base materials, correct? Typical dilution for batches run 10-20%.

Should I be letting the concentrates sit by themselves for longer before adding the ethanol, or is it ok to just mix it and then let it do its thing for a while? And at what point should I be worried about having screwed up my calculations?

And why does the pre-diluted stuff take shape so quickly when mixed? None of my sketches seem to need more than 24ish hours to develop
 

mnitabach

Basenotes Dependent
Nov 13, 2020
I suspect that when you pre-dilute materials with ethanol, some molecules react with EtOH (such as aldehydes forming acetals) and/or H20 (present a lot in 95% EtOH or in gradually increasing traces over time in nominally 100% EtOH which is hugely hygroscopic). When you mix non-diluted materials into a concentrate & then dilute in EtOH, these reactions have only just started, while in the pre-diluted materials they have already had a huge amount of time to occur.
 

Citroasis

Super Member
Jul 24, 2021
Pretty much what he said above. The prediluted bottles you use have been sitting in those bottles (in ethanol) for weeks to months already, and the reactions to alcohol have already settled in. So using those for trial batches already will smell like a finished product that has sat for a while.

Making large batches with undiluted materials will need to sit a while in ethanol for the same effect.

Time is not fun sometimes....I always wish I can push the clock forward a few weeks because I'm impatient.
 

hemmett

Super Member
Nov 28, 2017
I primarily work with all of my materials at 10% in ethanol.

When working on a blend Ive noticed that I can compose something, set it aside for a day, and then come back to it and it smells pretty much the way its going to smell within that time frame.

I will sometimes like what I smell, and set about to make a concentrate from the formula, using materials at 100%. Typically, I will combine those materials at their proper weights, often scaled up for batching, and will immediately add the ethanol , swish it all around to get the concentrated materials to go into solution, and then leave it on the shelf. after 24-48 hours, I sniff the batched bottle and immediately freak out that I have ruined something, or miscalculated some material, or added way too much cinnamon (most recent formula) because it smells NOTHING like what it did at 10% in the initial sketch.

I suspect this is a maturation issue? I need to be leaving these mixes to sit for weeks, especially if they're heavy with resins and base materials, correct? Typical dilution for batches run 10-20%.

Should I be letting the concentrates sit by themselves for longer before adding the ethanol, or is it ok to just mix it and then let it do its thing for a while? And at what point should I be worried about having screwed up my calculations?

And why does the pre-diluted stuff take shape so quickly when mixed? None of my sketches seem to need more than 24ish hours to develop
As you know I work the same way as you do. I can relate to what mnitabach wrote (not that I knew about this from a scientific point; so thanks for that explanation).

Out of experience I have noticed that blends w 100% raw materials take way more time to settle, sometimes weeks, compared to pre-diluted materials. It makes it hard to evaluate them if you don’t have patience and easier to overdose materials when you think a material isn’t doing anything. Especially (!!) w more naturals, as they are more complex than synthetics. This is why I eventually decided to work 10% prediluted, to speed up the process in making sketches.
 

mnitabach

Basenotes Dependent
Nov 13, 2020
One easy experiment to reveal that such reactions occur is to make a 10% EtOH dilution of methyl diantilis in a clear bottle. When you first make it, it looks yellowish. Over days to weeks, the hue becomes more pink & less yellow. While I'm not a chemist & wouldn't speculate as to the chemical reaction(s), this color change indicates a change in the absorption spectrum of photons by the contents of the bottle, thus indicating occurrence of some chemical reaction(s). While I haven't noticed any obvious change in scent character corresponding to the color change, I haven't done any careful side-by-side olfactory testing of new & aged EtOH dilutions of methyl diantilis.

Another thing worth considering when thinking about working with pre-dilutions in EtOH is that the reactions that occur in such dilutions can affect what reactions can subsequently occur when they are mixed together in compositions. And obviously there is no maturation of the mixture in fragrance concentrate before diluting in EtOH. So it seems very likely that the ultimate chemical composition of a well-macerated EtOH-diluted fine fragrance will be different depending on whether it was assembled directly from EtOH dilutions of components vs assembled as a concentrate, allowed to mature, and then diluted in EtOH. And how long the concentrate is matured before diluting in EtOH should surely have an effect on the final product as well.
 

Casper_grassy

Basenotes Dependent
May 5, 2020
I agree with Mike.

I will say it kind of sucks that many of us try to purchase many things and increase our palette via (typically) 15-30ml bottles just trying to learn, then diluting them for use/ease of use and extending what you get out of them .

Ironically Ruskin just mentioned throwing away 100g trials of what was probably 90+% undiluted materials. Taking this into context without dilutions your 15ml bottle is empty after one 100g trial.

Throughout my experience I always suspected there wouldn’t be a difference between pre-diluted and undiulted, up until years ago that Paul said he used everything undiluted. At the time I wondered why, it seemed annoying more than anything until I tried two blends. I always use 20% dilutions for everything so I could skip doing needless calculations, and in my head having 20% dilutions was equivalent to having “finished product undiluted quantities”.

Anyways I remember vividly it was an 11 line rose accord. First and foremost as mentioned, the color was much nicer of the undiluted blend, it smelled different, not vastly different but obvious differences as in some components would stand out more than the pre-diluted blends. I waited 2 weeks before diluting the blend for comparison.

After initial dilution, they became more similar. So I thought it was a waste of time, but I waited another week. After that, those same components that stood out while undiluted began to stand out more then after another day or two, up until another week the odor didn’t change at all for undiluted version, but it was definitely smoother and smelled more harmonious. Could I have used some bias towards what I was smelling? Perhaps, but as far as i’m aware, it was subjectively better.

So were the differences astronomical? No, but they were different. I will now say that I don’t think there is anything wrong with using all diluted materials because I do for most my trials, however based upon my formula I calculate how much is required to use and I will dilute “a little heavy” of that amount so I won’t have material sitting in the bottle. Why? Because it’s obvious there is inevitable oxidation from things like galaxolide, hydroxycitronellal etc. and probably everything else. If a material is left to sit in ethanol for a long enough time period, it thickens up, appears lower in volume and usually the odor is somewhat different. What does this mean to us? The dilution at that point, is no longer the original dilution you made, therefore if you are using diluted materials in ethanol that have been sitting in a bottle it could not be exactly what you think it is. And concentration absolutely plays a role in the finished product. So if you decide to use pre-diluted materials try not to dilute what’s more than needed.
 

mnitabach

Basenotes Dependent
Nov 13, 2020
For the overwhelmingly vast majority of materials, EtOH evaporates faster & so even if you have a 💯% impervious bottle, every time you open & use, the material gets a little bit more concentrated. And if you have shitty caps or over/under tighten, it's even worse.
 

hemmett

Super Member
Nov 28, 2017
For the overwhelmingly vast majority of materials, EtOH evaporates faster & so even if you have a 💯% impervious bottle, every time you open & use, the material gets a little bit more concentrated. And if you have shitty caps or over/under tighten, it's even worse.
True. I have read on here some folks therefore dilute in DPG instead (where possible).
 

mnitabach

Basenotes Dependent
Nov 13, 2020
True. I have read on here some folks therefore dilute in DPG instead (where possible).
Diluting in high boiling point solvents is a very good idea extremely high impact materials that need to be added to the fragrance concentrate in extremely small amounts. However, it is not relevant to the situation being discussed here, which is the assembly & testing of formulas for EtOH-based fine fragrance using EtOH dilutions of all your materials instead of first assembling a concentrate, maturing it, then diluting in EtOH.
 

Bmaster

Super Member
Sep 24, 2021
For the overwhelmingly vast majority of materials, EtOH evaporates faster & so even if you have a 💯% impervious bottle, every time you open & use, the material gets a little bit more concentrated. And if you have shitty caps or over/under tighten, it's even worse.
This! I would not trust a dilution with EtOH in a dropper bottle after a month. I have learned to dilute very powerful materials with a less volatile diluent to reduce evaporation. A 1% dilution with EtOH will sustain significant volume changes as compared to a 1% dilution with IPM or DPG. What's shocking is how quickly the evaporation occurs, over a period of several months you may find materials to be completely evaporate if using EtOH. Of course my droppers are egregious, although I have yet to find any droppers that claim to be evaporation proof.

My experience with maceration is limited, but naturals and smaller amounts of powerful materials tend to diminish over periods of time. Those filler AC's don't tend to suffer as often.
 

pkiler

Basenotes Plus
Basenotes Plus
Dec 5, 2007
True. I have read on here some folks therefore dilute in DPG instead (where possible).
I've stopped using DPG for major dilutions, because of experiencing plain DPG going off, and smelling bad.
So, I pick something different for those rare times when I actually dilute something.
 

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