"Has my orris butter gone bad?" — the problem isn't the material, it's evaluating everything at 1%

Someone on r/DIYfragrance posted a photo with a very specific question:

"Is Orris Butter (10% in TEC) supposed to look like this? I ordered it last month. It's my first time ever seeing or smelling it."

"I am going through all my materials assessing how they smell at different time intervals, and while it is being listed as a base material I couldn't smell it anymore after 30 minutes."

"And I also already thought this was looking a little too thick for something already diluted at 10%? But don't own TEC or other materials diluted in TEC, so I thought maybe TEC is quite thick as well."

"If this has gone bad then it's the second time at this shop that I've gotten a material that has gone bad, so then I won't order at them anymore."

Three claims: too thick, can't smell it, possibly spoiled. All three are checkable, and none of them turns out to be about a spoiled material.

The short version

• "Orris butter is a solid at room temperature" is correct. The database's Iris pallida orris rhizome concrete butter record gives a melting point of 40–46 °C and an appearance of "pale yellow to yellow paste". Not flowing at room temperature is its normal state.
• The reason is in the composition. A 2018 GC-MS analysis of Ukrainian Iris pallida measured, in the rhizome oil: myristic acid 56%, lauric acid 15.42%, capric acid 14.50%. That is 86% fatty acids, and myristic acid alone melts around 50 °C.
• "TEC is quite thick as well" is not correct. TEC melts at −46 °C and its appearance is "colorless clear oily liquid". What is thick is the orris, not the solvent.
• The real problem is evaluation strength. They wrote that "1% is where I assess most of my materials". Of the 802 database records carrying a recommended evaluation strength, 527 (66%) say 10%, 204 (25%) say 1%, and 45 (5.6%) say 0.1%.
• Of the 120 most-used corpus materials, the database recommends 1% for only 6 of them, and 10% for 15.
• And the control they used against olfactory fatigue is weaker than it feels. A 2000 review notes that stimulating one nostril produces adaptation in both nostrils, and that the time course of adaptation and recovery depends on the concentration and the duration of exposure. Leaving the room helps; it is not a clean reset.

Thick: the database answers directly

The first reply was confident:

"Why you think it's gone bad? … This is completely normal. Orris butter is a solid at room temperature, even diluted in tec. Just keep it in your pocket and you'll see it turn liquid again. Orris butter doesn't 'go bad'. It actually ages very nicely over the years." (Junior_Ad4596)

The database agrees. Iris pallida orris rhizome concrete butter (CAS 8002-73-1, 40 suppliers):

Field	Value
Appearance	Pale yellow to yellow paste (est)
Melting point	40.00–46.00 °C
Odour	Woody, fatty, violet, fruity, sweet, floral, warm
Strength	Low

Forty to forty-six degrees. Far above guaiacol (28–32 °C) and diphenyl oxide (27 °C), both of which melt in summer. Orris butter is a paste at any room temperature a person can live in.

Mykhailenko's 2018 GC-MS analysis supplies the reason. Steam-distilling rhizomes and leaves of Ukrainian Iris pallida (yields 0.20% and 0.03%), the rhizome oil gave 18 identified components, dominated by:

Component	Content
Myristic acid (tetradecanoic)	56%
Lauric acid (dodecanoic)	15.42%
Capric acid	14.50%
α-irone	2.85%

The top three are all saturated fatty acids, 86% together. Myristic acid is a white solid wax and so is lauric acid. That is why "butter" is in the name: it is literally a block of fat, with the irones dissolved as a small part of it.

The paper also carries a line useful to a buyer: "α-irone and γ-irone contents are accepted as the most significant criteria of the commercial quality of Iris essential oil." What you pay for is those few per cent, not the 86%.

As for TEC:

Field	Value
Database category	Carrier solvents/diluents for flavors and/or fragrances
Appearance	Colorless clear oily liquid (est)
Melting point	−46.00 °C
Specific gravity	1.135–1.139 @ 25 °C
Odour strength	None

Minus forty-six. TEC is not thick. This round's material guide covers it.

Can't smell it: this answer isn't on the material's side

The poster added their notes, which are careful:

"0000: Soft, earthy, powdery and floral. Also has a note that reminds me of raw potato peel. 0005: Less earthy, just soft, powdery and floral. Potato peel has gone. 0015: Overall a lot more faint, similar scent profile. 0030: Can't smell it anymore."

"I came back after being away for an hour and still nothing."

"It's at 1%, and I've read that it's supposed to be pretty strong at 1% as well."

One reply said 30 minutes is about right for orris butter; another that it is often classified as a middle note rather than a base. But the most useful is this:

"1% is too low IMO. Most materials benefit from being evaluated at 10%, 1% for stronger ones and 0.1% for nuclear stuff." (quodo1)

"It does matter. Let's take your orris butter as an example: it contains 20% irones. By diluting the material at 1%, you end up having a 0.2% solution of irone (+ all the other stuff, some of which can be very faint), which is not really that much."

And the poster's reply is the line in this thread that most deserves an answer:

"Does it matter much? I figured it would be easier to smell all the nuances that you maybe miss on higher dilutions."

That question deserves a serious answer, because the instinct points the right way and has exactly one thing backwards.

What the database says

I pulled the strength field for all 42,225 records.

One limit first: only 802 (1.9%) carry a recommended evaluation strength in that field. For the vast majority, the database gives only medium/low/high, or nothing.

Among those 802:

Recommended evaluation strength	Records	Share
10.00%	527	65.7%
1.00%	204	25.4%
0.10%	45	5.6%
50.00%	12	1.5%
0.01%	9	1.1%
5.00%	4	0.5%
20.00%	1	0.1%

quodo1's rule of thumb — 10% for most, 1% for stronger ones, 0.1% for nuclear stuff — reproduces the database's distribution. 66%, 25%, 5.6%. That is not a feeling; it restates a three-tier scheme that actually exists.

Crossed against the 120 most-used corpus materials:

Database recommendation	Materials	Examples
10%	15	Coumarin, eugenol, vanillin, β-ionone, α-ionone, ethyl vanillin, phenyl acetaldehyde, raspberry ketone, benzaldehyde
1%	6	Indole, α-damascone, galbanum oil, ethyl butyrate, Ambroxan, β-damascone
Strength only, no recommendation	55	Linalool, benzyl acetate, phenethyl alcohol, citronellol, linalyl acetate, geraniol…
Nothing at all	44	The trade names

Six of 120 should be smelled at 1%.

The poster smells everything at 1%. For those six they are right; for the other fifteen they are ten times too dilute.

For the 55 with a strength but no recommendation, their doses in formulas make the point:

Material	Formulas	Median dose in formulas
Linalool	338	6.00%
Benzyl acetate	317	5.50%
Phenethyl alcohol	274	10.00%
Citronellol	220	6.00%
Hydroxycitronellal	161	8.50%
Benzyl salicylate	159	9.63%
α-hexyl cinnamaldehyde	157	9.71%

Phenethyl alcohol's median dose in formulas is 10%. Evaluating it at 1% means smelling it at a tenth of where it lives in real work. That is not seeing more detail; it is turning it down below hearing.

The poster's instinct — that a low dilution lets you hear the fine detail — does hold for some materials. High-strength materials do bury their own layers at high concentration, and that is exactly why indole and the damascones are recommended at 1% and guaiacol at 1% or less. But that reasoning runs in one direction only. Applied to a material whose strength field says low, it does not make it finer; it makes it absent.

And orris butter's strength field says low.

I cannot vouch for that 20%

quodo1's arithmetic deserves separate handling, because the arithmetic is right and the input is one I cannot verify.

He says orris butter contains 20% irones, so a 1% dilution gives a 0.2% irone solution. That multiplication is entirely correct, and it is precisely the dilution-of-a-dilution problem this series keeps running into.

But I could not confirm the 20%. The published figure I found is from the 2018 paper: α-irone at 2.85% in the steam-distilled rhizome oil of Ukrainian Iris pallida.

Those two numbers cannot be compared directly, and the reasons should be stated:

• The paper measured a steam-distilled essential oil, not the commercial product called orris butter or concrete.
• Commercial orris butter is sold graded by irone content; different concentrations exist on the market, and 20% may refer to a specific grade.
• Origin, species (pallida versus germanica) and years of rhizome ageing all change irone content — the paper itself says irone content is the commercial quality criterion.

So my position is: quodo1's method is correct, and the 20% is something to confirm with your supplier, not with me. If you bought a 10% irone grade, then diluted to 1%, what you have is 0.1% irone.

There is a nastier possibility too. The poster bought a product that is 10% in TEC, and then wrote "it's at 1%". That sentence has two readings:

1. They diluted the 10% product down to 1% orris butter — taking a tenth of a tenth
2. They treated the 10% product as the raw material and made a 1% evaluation dilution from it, in which case the actual orris butter is 0.1%

The thread does not resolve it and I cannot judge from outside. But the two readings differ tenfold, and this is the single easiest error to make with a pre-diluted product. If it is the second, the irone on their smelling strip may be a few hundred parts per million.

"I've left the room in between" — a weaker control than it feels

The poster carefully rules out one confounder:

"I doubt it's olfactory fatigue cause I've left the room inbetween smelling."

Two others point the same direction:

"Try diluting it further, could be overwhelming your nose receptors and causing immediate olfactory fatigue" (Mammoth-Trip-4522)

"Irones and ionones can blow out your nose quickly. Try diluting more." (Infernalpain92)

Dalton's 2000 review of olfactory adaptation in Chemical Senses makes this concrete.

Three points bear on the question.

1. Repeated or prolonged exposure to an odorant typically leads to stimulus-specific decreases in olfactory sensitivity to that odorant, and sensitivity recovers over time in the absence of further exposure. Psychophysical analysis shows adaptation both elevates thresholds and reduces responsiveness to suprathreshold stimulation.
2. The magnitude of the decrease and the time course of adaptation and recovery depend on the concentration of the odor and on the duration of exposure.
3. On mechanism: monorhinal stimulation results in adaptation in both the ipsilateral and contralateral nostril, though the ipsilateral is more profound and recovers more slowly. Other studies found relatively small decreases in peripheral response after repeated stimulation despite substantial reductions in perceived intensity.

The third point is the crux. Adaptation happens not only in the nose but at more central levels too. Leaving the room stops further exposure, which is the right move; it does not instantly erase a central-level adaptation, and how long recovery takes depends on the concentration and duration of what was smelled.

To be fair: the poster's approach is not wrong, and leaving is better than not leaving. It is just weaker than it feels. And if the actual cause is too low a concentration rather than fatigue, leaving the room any number of times will not change the outcome — they have not yet separated those two hypotheses.

Separating them is simple, and one reply already supplied the method: make a 10% and smell it beside the 1%. If the 10% is still there at 30 minutes, the problem is concentration. If both vanish, then fatigue or the material itself becomes the question.

The corpus does the same thing

One number, to show that working from dilutions is not a beginner's habit.

The 954 published formulas contain 17,481 material entries, and 2,179 of them (12.5%) carry a percentage in the name — the formula's author entered a dilution at some strength as a single line, as in "indole 10%" or "aldehyde c-12 10%".

One entry in eight is a dilution. Which is why "what strength is this bottle actually" goes wrong repeatedly in formulas: get one of the two dilution steps unrecorded and you are off by ten.

What I learned this round

I had planned to build the piece around why orris butter is a solid, because that question is the easiest to check and has the cleanest answer. Once checked, that section took three paragraphs, and it was not the answer the poster most needed. Their real trouble was not being able to smell it, which is what made them suspect a spoiled material.

And the answer to that sits inside a line they wrote in passing: "1% is where I assess most of my materials." They offered it as background, not as the problem. The only person in the thread who noticed that line was quodo1, and his reply is buried in the lower half.

That changes how I read threads: the sentence the asker considers unimportant is often where the answer is.

What you can actually do

• Use three evaluation tiers: 10% for most, 1% for strong ones, 0.1% for nuclear material. That matches the database's distribution (66% / 25% / 5.6%).
• Do not put everything at 1%. Of the 120 most-used corpus materials, only 6 belong there.
• Check the strength field first. Smelling a material rated low at 1% is close to not smelling it.
• When you buy a pre-diluted product, write both dilution steps on the label. "10% in TEC, further diluted to 1%" and "1% of the 10% product" differ by ten.
• When you suspect fatigue, make one ten times stronger and compare side by side. That separates "not enough material" from "tired nose" better than leaving the room.
• Paste does not mean spoiled. Something melting at 40–46 °C looks like that at room temperature. Pocket or warm water bath.

What this doesn't establish

• Only 1.9% of materials carry a recommended evaluation strength. The 66% / 25% / 5.6% split is the distribution within those 802 records, not across the database. For the remaining 41,423, no recommendation exists.
• The database does not document where the recommended strengths come from or how they were set. I cannot judge who decided them or on what basis.
• I did not verify the 20% irone figure. The 2018 paper measured a steam-distilled essential oil (α-irone 2.85%), a different product from commercial orris butter, so the two numbers do not refute each other.
• Mykhailenko 2018 measured Ukrainian Iris pallida — one origin, one species. The 86% fatty acid finding explains the direction of "why butter is solid" but cannot stand as a composition table for all orris butter.
• Dalton 2000 is a review. What I cite are the general principles it assembles, not the numbers of any single experiment. It also states explicitly that most psychophysical studies of adaptation have not differentiated the peripheral and central processes.
• I have not smelled this orris butter. This piece is database queries, papers and arithmetic, not a sensory report. Only the poster can confirm what their material is actually like.