6.4 Testing & Evaluating a Fragrance Formula
Creating a fragrance is an art, but testing and evaluating it is the key to ensuring its quality, balance, and longevity. A well-tested fragrance is more likely to be successful in perfumes, body sprays, candles, soaps, and other scented products.
This guide will cover:
✅ Why testing is important in fragrance development
✅ Key testing methods for evaluating performance
✅ How to analyze longevity, projection, and balance
✅ Practical example: Testing a citrus-floral fragrance
1️⃣ Why Testing & Evaluation Is Important
A fragrance may smell amazing when freshly blended, but how does it perform over time? Testing helps determine:
✔ Scent Evolution: How the top, middle, and base notes develop over hours.
✔ Longevity: How long the fragrance lasts on skin, paper, or fabric.
✔ Diffusion & Projection: How far the scent spreads.
✔ Stability: How well the fragrance holds up in different conditions.
✔ Balance: If one note is too strong or weak.
2️⃣ Key Testing Methods in Perfumery
🔹 1. Blotter Testing (Paper Strips)
Purpose: Quickly evaluate the structure and evolution of a fragrance.
Steps:
1️⃣ Dip a fragrance blotter (paper strip) into the scent (5-10% dilution in ethanol).
2️⃣ Let it dry for 15-30 seconds to allow alcohol to evaporate.
3️⃣ Smell it at different time intervals: immediately, after 15 minutes, 1 hour, 4 hours, etc.
4️⃣ Take notes on how the scent changes over time.
💡 Tip: If a fragrance disappears too quickly, it may need more fixatives like musks or resins.
🔹 2. Skin Testing (Wear Test)
Purpose: See how the fragrance interacts with body heat and skin chemistry.
Steps:
1️⃣ Apply one drop or spray on your wrist or forearm.
2️⃣ Avoid rubbing—it can alter the natural evaporation process.
3️⃣ Smell and take notes at different intervals (10 min, 1 hour, 4 hours, 8 hours, etc.).
4️⃣ Observe how the scent develops and how long it lasts.
💡 Tip: Ask multiple people to test it, as skin chemistry varies from person to person.
🔹 3. Fabric & Clothing Test
Purpose: Evaluate how well a fragrance sticks to clothes.
Steps:
1️⃣ Spray the fragrance on a cotton fabric or a t-shirt.
2️⃣ Smell the fabric at different times (immediately, after 2 hours, next day).
3️⃣ Compare how well it lasts compared to the skin test.
💡 Tip: If the fragrance disappears too quickly on fabric, adding fixatives like benzoin, ambroxan, or Galaxolide may help.
🔹 4. Diffusion & Projection Test
Purpose: Check how far the scent travels and how strong it is in a room.
Steps:
1️⃣ Spray the fragrance in a small room (like a bathroom).
2️⃣ Step out and return after 5 minutes to check how strong it is.
3️⃣ Have someone stand 3-6 feet away and check if they can smell it.
4️⃣ Observe how long the scent lingers in the air.
💡 Tip: Citrus and floral notes diffuse quickly, while woody and musky notes last longer.
🔹 5. Heat & Stability Testing
Purpose: Ensure the fragrance remains stable over time and under different conditions.
Steps:
1️⃣ Store the fragrance in different environments:
- Room temperature (20°C/68°F)
- Refrigerator (5°C/41°F) for 24 hours
- Heat test (40°C/104°F) for 24 hours
2️⃣ Check for changes in color, separation, or scent.
💡 Tip: If the fragrance darkens or smells off, some ingredients may be unstable and need reformulation.
3️⃣ Practical Example: Testing a Citrus-Floral Fragrance
🎯 Goal: Test a new citrus-floral fragrance for balance, longevity, and projection.
Fragrance Formula:
✔ Top Notes: Lemon (25%), Bergamot (20%), Orange (15%)
✔ Middle Notes: Jasmine (15%), Rose (10%)
✔ Base Notes: Musk (10%), Sandalwood (5%)
Step 1: Blotter Test
🔹 Lemon & bergamot smell fresh at first.
🔹 After 15 minutes, jasmine and rose start appearing.
🔹 After 4 hours, only musk and sandalwood remain.
✅ Result: Citrus notes disappear quickly → Needs fixatives.
Step 2: Skin Test
🔹 Applied on wrist → Smelled fresh in the first 30 minutes.
🔹 After 2 hours, the floral notes became dominant.
🔹 After 6 hours, only a faint musky scent remained.
✅ Result: Longevity is moderate (6 hours) → Could be improved with longer-lasting base notes.
Step 3: Fabric Test
🔹 Sprayed on a cotton cloth.
🔹 Still detectable after 8 hours.
✅ Result: Performs better on fabric than skin.
Step 4: Diffusion Test
🔹 Sprayed in a small room.
🔹 Could smell it from 3 feet away.
🔹 After 30 minutes, the scent faded significantly.
✅ Result: Needs more projection power → Add Iso E Super or Hedione.
Step 5: Stability Test
🔹 Stored in a warm (40°C) environment for 24 hours.
🔹 No color change, but citrus notes weakened.
✅ Result: Might need an antioxidant (BHT) to protect citrus oils.
4️⃣ How to Improve the Formula Based on Testing
🔸 Problem: Citrus fades too fast.
✅ Solution: Add a fixative like Ambroxan or Benzoin.
🔸 Problem: Projection is weak.
✅ Solution: Add Iso E Super or Hedione for better diffusion.
🔸 Problem: Heat affects citrus notes.
✅ Solution: Use BHT (Butylated Hydroxytoluene) as an antioxidant.
Final Thoughts & Next Steps
✔ Testing is critical to refining a fragrance formula.
✔ Use multiple methods (blotter, skin, fabric, projection, stability).
✔ Keep detailed notes on how a fragrance evolves over time.
✔ Adjust the formula based on test results before finalizing production.
🚀 Next Challenge: Try testing a woody or spicy fragrance and see how it performs compared to citrus-floral blends!