Perfume making experiments often are made with small quantities of fragrance oils. For example, we might need to add 0.3 drops of Patchouli to a mix. It may seem that adding 3 drops of a 10% dilution of Patchouli will do the job. Not so fast!
In the following experiment I filled small vials with the same quantity of different full strength oils as well as 50% diluted oils using pipettes. Check out the results:
1. Alcohol (44 drops)
2. Jojoba Oil (31 drops)
3. Patchouli (31 drops)
4. Bergamot (37 drops)
5. Bergamot 50% (45 drops)
6. Patchouli 50% (44 drops)
7. Labdanum 50% (46 drops)
8. Tagettes 50% (45 drops)
9. Black Pepper (38 drops)
10. Marigold (35 drops)
Once an oil been diluted in alcohol its viscosity (even for resinoids like Labdanum and Tagettes) becomes very much similar to viscosity of perfume alcohol itself.
As a rule of thumb when adding diluted oils to the formula the number of drops should be increased by adding extra 1/3 to the count.
In case of Patchouli we should actually add 4 drops of 10% dilution instead of 3 drops in order to match the required 0.3 drops of undiluted Patchouli (3+3/3=4).
Also if you are using the tip of the vial cap to dispense diluted oils like it is shown in the picture:
it is necessary to double the number of drops.
Example, if you need to add 0.3 drops of Patchouli and you are dispensing a 10% dilution of Patchouli from a vial using its cap instead of a pipette, you should actually add 6 drops!
Have fun counting!