Concentration: What It Is and What It Isn't
The EDP or EDT in a fragrance name refers to ratio, not quality — contrary to what is often assumed. That ratio is the percentage of fragrance oil (scent concentrate) dissolved in alcohol. When the top note fades, this layer takes centre stage — but the percentage alone does not determine its strength.
The most common mistake is the assumption: "If I raise the concentration, the fragrance will last longer." In reality, longevity is primarily determined by the volatility of the raw materials in the formula. A citrus-heavy extrait can fade quickly; a low-concentration composition built around amber and musk can last for hours. Concentration is a starting framework, not a performance guarantee.
Categories: EDC, EDT, EDP, Extrait
Four principal categories circulate within the industry. The boundaries between them are not fixed; they shift from one manufacturer to another. The table below is an approximate framework, not dogma. Test and refine with your own product.
| Category | Approximate Fragrance Oil Ratio | Typical Use | Character |
|---|---|---|---|
| Cologne (EDC) | 2–5% | Refreshing, frequent reapplication | Light, fleeting, citrus-focused |
| EDT (Eau de Toilette) | 5–12% | Daytime, warm climates | Bright opening, lively projection |
| EDP (Eau de Parfum) | 12–20% | Versatile, main product | Balanced, full-bodied, settled |
| Extrait (Extrait / Parfum) | 20–30% | Intensity with minimal application | Close-wearing, dense, base note-dominant |
Choosing the Right Concentration for Your Target Product
First ask what the product needs to do, then determine the ratio. A room spray, a skin fragrance, and a hair mist do not operate at the same percentage. Fragrance concentration ratios are a directional guide, not a fixed formula.
- Define the purpose
Are you after close-skin intimacy or a room-filling trail? For intimacy, lean towards extrait territory; for ambient effect, consider a well-structured EDP.
- Read the raw material structure
If the fragrance oil is citrus/volatile-heavy, raising the concentration alone won't solve longevity — reinforce the base notes. If it is amber/oud/musk-heavy, it may project strongly even at a lower ratio.
- Start low
Begin below your target concentration and observe how the scent develops. It is easy to go higher; it is difficult to pull back.
- Check solubility
As the concentration rises, so does the risk of cloudiness. Test clarity at every step.
- Verify IFRA compliance
Before finalising the ratio, read the fragrance oil's compliance statement. Limits apply per individual ingredient, not to the total concentration.
Simple Calculations and Example Ratios
The maths is straightforward: the percentage of fragrance oil in your total volume, with the remainder being alcohol (and a small amount of water if required). The table below offers a starting framework based on 100 ml. Don't treat these numbers as sacred — every formula finds its own balance.
| Target | Fragrance Oil (%) | Fragrance Oil in 100 ml | Alcohol + Small Amount of Water |
|---|---|---|---|
| EDT trial | 10% | 10 ml | ~90 ml |
| EDP trial | 15% | 15 ml | ~85 ml |
| EDP upper limit | 20% | 20 ml | ~80 ml |
| Extrait trial | 25% | 25 ml | ~75 ml |
Water is listed within "the remainder" because the amount required varies depending on whether the fragrance oil remains clear at a given ratio. Work with alcohol first, then add water drop by drop while monitoring clarity. If cloudiness appears at a certain point, pull back.
The work doesn't end once you've mixed everything. Maceration comes into play — and it is more than simply waiting. Through the interaction of alcohol and fragrance oil, along with mild esterification, the scent settles and the raw "alcohol bite" softens. Maceration (at room temperature, ~15–20 °C), protection from light, and finally cold filtration (to remove waxy materials) all refine the composition.
Common Mistakes and Frequently Asked Questions
Many people get the ratio right but lose their way in the details. Avoid these three traps: equating concentration with longevity, adding too much water, and skipping maceration. Everything else is your signature.
If you are new to this, build the fundamentals in order — choosing a concentration only makes sense alongside your choice of raw materials and note architecture. (See: beginner's guide to making fragrance from scratch and the top-middle-base note pyramid.)
Will raising the concentration automatically push me over the safety limit?
Why does cloudiness appear when I reach extrait-level concentrations?
Related Articles
Beginner's Guide to Making Fragrance from Scratch
A comprehensive cornerstone article covering materials, equipment, and first steps for anyone with no prior experience. All the es
Read →The Difference Between Fragrance Oil, Perfume Oil, and Essential Oil
Clarifies three frequently confused concepts, helping buyers choose the right product and reducing incorrect orders and returns.
Read →How to Build a Top-Middle-Base Note Pyramid
The logic behind the scent pyramid and how to design a balanced composition — an approachable introduction to formulation for aspiring makers.
Read →