Accord — A Single Olfactory Impression
An accord is a structure in which two or more raw materials combine to create a single olfactory impression. Think of it like several musical notes played simultaneously to produce one harmony. Rose smells like rose on its own; patchouli smells like patchouli. But when they meet in the right proportions, the result is something entirely new — no longer the sum of its parts.
An accord is the building block of a perfume. A well-crafted formula is not a random collection of raw materials — it is a structure of interlocking accords. The key word here is balance: how many grams of each material you add determines the destiny of the scent.
When defining an accord, we ask three questions: Which core raw materials carry the impression? Which bridge material links them together? And which material is dominant on stage, and which is supporting?
Raw Material Weight Balance: Strength ≠ Proportion
The most common mistake beginners make is mixing raw materials in equal quantities. Yet every raw material has a different odour strength. 1 gram of vanilla and 1 gram of aldehyde do not carry the same weight; the aldehyde will overpower the composition while the vanilla is barely perceptible.
This is where odour threshold comes in: the lowest concentration at which a material can be perceived. Materials with a low threshold take over the stage even in tiny amounts. That is why, when building an accord, you balance effective strength — not grams.
The practical solution: keep potent raw materials as diluted solutions. Preparing 1% or 10% dilutions prevents a single drop from upending the entire composition. This way you make fine adjustments not with less solvent, but with less material.
| Raw material type | Typical odour strength | Recommended working dilution | Role in the accord |
|---|---|---|---|
| Aldehydes, isobutyl quinoline | Very high | 1% or below | Modifier (adds colour/character) |
| Musk, ambroxide | High | 10% | Fixative (anchors the scent) |
| Rose, jasmine accord | Medium | 10–100% | Core theme |
| Citrus (bergamot, lemon) | Low–medium, volatile | 100% | Diffusive (top note) |
| Base woods (cedar, vetiver) | Medium | 10–50% | Structure / fixation |
Read the logic of this table alongside the Fixative–Diffusive–Modifier architecture: fixatives anchor the scent to the skin, diffusives carry it into the air, and modifiers add character and colour. A well-built accord should contain all three.
Step-by-Step: Building an Accord from Scratch
You build an accord through discipline, not chance. The sequence below starts with a simple three-part accord and builds up gradually. A classic example: an amber accord (vanilla + labdanum + woody).
- Choose your theme
Decide what the accord is meant to express: amber, fougère, a rose-patchouli axis? If you start with a vague goal, the result will be equally vague.
- Define the core
Start with 2–3 raw materials. More will only create confusion. Build the skeleton first; add ornamentation later.
- Start with equal strength, not equal weight
In your first trial, keep each ingredient at an equivalent perceived strength: try potent materials at 1% dilution, medium-strength ones at 10%. Work by gram on a precision scale rather than counting drops.
- Evaluate on a blotter
Smell the blend, but make your final judgement over time. When the top note fades, the base takes the stage; the accord's true character becomes clear after 30–60 minutes.
- Change one variable at a time
Adjust only one raw material's proportion per trial. If you change two things simultaneously, you will never know which one made the difference.
- Add a bridge material
If two ingredients don't bond well, introduce a bridge: materials such as linalool or dihydromyrcenol fill in the gaps.
- Rest and reassess
Leave the accord for a few days, then smell it again. During maceration (the process by which the scent settles through the interaction of alcohol and fragrance oil), the balance can shift.
Record-Keeping Discipline and Common Mistakes
Half of building an accord is chemistry; the other half is bookkeeping. A perfumer who keeps no records can never reproduce a beautiful scent. Number every trial, add the date, write down the proportions.
Log the following in your notebook: trial number, name of each raw material, dilution percentage, amount added in grams or percentage, date, and time-stamped scent notes (at 10 minutes, 1 hour, the following day). Evaporation kinetics and scent curves only become intelligible through these records.
| Common mistake | Consequence | Solution |
|---|---|---|
| Mixing in equal grams | The most potent material drowns everything out | Balance by strength; use diluted solutions |
| Starting with too many raw materials | A muddy, unreadable scent | Start with 3–5 ingredients, add gradually |
| Judging from a single evaluation | The top note misleads; the base disappoints | Evaluate repeatedly across multiple time points |
| Keeping no records | Success cannot be replicated | Keep a numbered, percentage-based, dated notebook |
| Leaving IFRA compliance until the end | The formula must be reworked at certification stage | Check raw material compliance from the outset |
A word of caution: IFRA limits are set not against the total fragrance oil proportion, but against individual materials, allergens, and product category (leave-on / rinse-off) within the fragrance oil. Before scaling up your accord, read the compliance declaration for every raw material you are using. Otherwise, a beautiful accord can become an unsellable product.
Taking an Accord into a Formula and Scaling It Up
Once you have a consistent accord in hand, the work has not ended — it has begun. Turning an accord into a full perfume means bringing it together with other accords to establish the final proportions.
When your concentrate is ready, you combine it with alcohol. Be patient here: adding too much water to high-strength ethanol disrupts solubility and causes cloudiness and phase separation. Keep the water content low — start with a small amount, test for clarity, and if needed use an appropriate perfumer's alcohol or co-solvent.
Apply maceration for maturation (at room temperature, ~15–20 °C, protected from light), then remove waxy compounds via cold filtration. This softens the harsh "alcohol strike" on opening and allows the accord's true balance to come to the fore.
One final point: longevity and sillage are not solely determined by the fragrance oil concentration. What matters is the volatility of the raw materials. A high-concentration accord heavy in citrus can fade quickly; a lower-concentration accord laden with amber, oud, and musk can linger for hours. Concentration alone does not determine performance — the structure of the formula and the volatility balance do. The rest is your signature.
How many raw materials should an accord contain?
Why should I use raw materials in diluted form?
Why do my proportions go wrong when I scale up an accord?
Related Articles
Evaporation Kinetics and Scent Curves
The evaporation curves of top, middle, and base notes over time; understanding why a fragrance opens the way it does.
Read →Fixative–Diffusive–Modifier Architecture
The three functional layers of a formula: the role and balance of fixative, diffusive, and modifier molecules.
Read →Odour Threshold and Dosage Optimisation
Why some molecules dominate at trace levels: the concept of perception threshold and the right dosage strategy.
Read →