How to dilute perfume materials by mass

The two numbers you need

To prepare a stock by mass, choose the target total mass and the target strength. For a 10 g stock at 10%, the undiluted material mass is 10 × 0.10 = 1 g. Solvent makes up the remaining 9 g. The material is one tenth of the complete mixture, not one tenth of the solvent alone.

A common mistake is adding 1 g material to 10 g solvent and calling the result 10%. The final mass is 11 g, so the material concentration is 1 ÷ 11 × 100, approximately 9.09%. The error is small enough to look plausible and large enough to matter when repeated throughout a formula.

Choose the solvent from the material’s needs

A working dilution needs a solvent in which the material dissolves at the intended strength and conditions. Ethanol, dipropylene glycol and other perfumery solvents are not interchangeable simply because each can be called a diluent. Consult the supplier’s information for the actual material and consider the carrier of the eventual study.

A clear solution today does not prove that a stronger solution, a colder room or a different final blend will behave the same way. Crystals, layers or persistent cloudiness are observations to investigate, not a signal to add a random household ingredient. A bought stock with a documented solvent can be a practical starting point.

Make a stock from an existing stock

The same arithmetic works with a pre-diluted input. To make 20 g at 1% from a 10% stock, you need 0.2 g neat material in total. Each gram of the existing stock contributes 0.1 g material, so weigh 2 g of stock and add 18 g compatible solvent. The final 20 g contains 0.2 g material.

The general formula is input stock mass = target total mass × target strength ÷ input strength, with both strengths expressed on the same basis. Added solvent is target total mass minus input stock mass. This calculation assumes you are diluting the same material and that the added solvent contains none of it.

Use a weighing sequence you can audit

Calculate the target masses before opening bottles. Place the labelled container on the scale and record additions in a way that lets you reconstruct the actual mass of each input. Taring between additions is convenient; keeping cumulative target and actual readings is another approach. Pick one method and use it consistently.

If you overshoot a material, do not silently write the planned number. You may be able to recalculate the whole dilution around the actual addition. For instance, 1.04 g material requires a 10.40 g final mass for a 10% stock, so the solvent addition becomes 9.36 g. Only do this when the container and batch plan allow it.

1. Confirm the material, stock strength, solvent and target mass.
2. Prepare the label and calculate both additions.
3. Weigh and record the actual input mass.
4. Add the calculated compatible solvent and close the container.
5. Mix as appropriate, inspect the result and record any undissolved material.

Label for the person you will be next month

Write the material name, supplier grade, strength with “w/w” or “by mass,” solvent, preparation date and batch reference. “Vanillin 10% w/w in ethanol” carries much more useful information than “vanilla.” Include the supplier lot when available so that the stock connects to its source bottle.

A prepared dilution is an inventory item. Record how much you made and preserve the recipe. This lets you calculate both the aromatic contribution and the cost when you later use two grams of that stock. If a label becomes unreadable, do not reconstruct the identity from smell alone.

Know when dilution cannot solve the problem

Adding solvent can only reduce concentration. You cannot make a 20% stock from a 10% stock by adding more solvent; the calculator should reject that request. Evaporating solvent is not the inverse of this simple weighing method because composition and losses would need separate control.

Working strength is also not a declaration of skin suitability. These calculations answer how much to weigh. Handling requirements and suitability for a finished application come from the material documentation and an assessment of the full product.