How to Change a Material's Dilution in a Perfume Formula

Why the choice matters

A diluted row has two parts: the material and the solvent carrying it. "Ambroxide 10% in DPG, 5.00 g" is 0.50 g of ambroxide and 4.50 g of DPG. Change the dilution to 5% and something must give — the 5.00 g, the 0.50 g, or another row. The reasons you might change a dilution point to different answers:

• You have run out of the 10% stock and only have a 5% solution — you want the same formula, so the pure material must stay the same.
• The material was too loud — you want less of it, and weighing the same amount of a weaker solution is a quick way to halve it.
• You want finer control over a tiny amount — the material should stay the same, but the total of a production formula must not move.

The three percentages that describe a row — formula %, absolute % and relative % — react differently to each method. They are defined in formula %, absolute % and relative %; the tables below show them moving.

The starting formula

An illustrative 100 g concentrate. DPG on its own line is a solvent row: it adds weight but no fragrance.

Ambroxide's relative % — its share of the pure fragrance material — is 0.50 ÷ 75.50 = 0.6623%. That is the figure that describes how much of the scent it is. Now switch it from 10% to 5%, three ways.

Method 1: keep the row's weight

Weigh 5.00 g of the 5% solution instead of 5.00 g of the 10% one.

• Pure ambroxide falls to 0.25 g; the row carries 4.75 g of DPG instead of 4.50 g.
• The formula still totals 100.00 g, and no other row changes weight.
• Total pure material falls to 75.25 g. Ambroxide's relative % halves, to 0.25 ÷ 75.25 = 0.3322%. Every other material's relative % rises very slightly — Iso E Super from 39.735% to 39.867%.

Use it when you mean to reduce the material. It is a clean, visible way to halve a row. Avoid it when you only ran out of a stock solution: the formula you weigh is no longer the formula you approved.

Method 2: keep the pure material

Weigh twice as much of the weaker solution: 10.00 g of the 5% solution carries the same 0.50 g of ambroxide.

• The row grows by 5.00 g, all of it DPG. The formula now totals 105.00 g.
• Total pure material is unchanged at 75.50 g, so every relative % is unchanged — the scent's composition is the same.
• Every formula % changes: Iso E Super is now 30 ÷ 105 = 28.571% of the weight instead of 30%. Ambroxide's absolute % falls from 0.50% to 0.4762%, because the same material sits in more total weight.

Use it when you want the same fragrance and do not mind the concentrate carrying a little more solvent. Watch the knock-on effect: if the concentrate is later diluted in alcohol by weight, the extra DPG counts as concentrate, so the finished perfume is very slightly weaker in fragrance material than before.

Method 3: keep the pure material and the total

Weigh 10.00 g of the 5% solution, and take the extra 5.00 g out of the DPG row, which falls from 20.00 g to 15.00 g.

• The formula still totals 100.00 g and still contains 75.50 g of pure material.
• Every relative % and every absolute % is unchanged; only the ambroxide and DPG rows' weights move.

Use it when the formula is approved or in production and must not change in any measurable way. It needs a solvent row large enough to give up the difference, and the same solvent on both sides — swapping DPG for alcohol changes the product.

When the solvent row is too small

Switch the same material from 10% to 1% instead and Method 3 would need the row to grow from 5.00 g to 50.00 g — 45.00 g more — while the DPG row holds only 20.00 g. Taking all 20.00 g still leaves 25.00 g unaccounted for, so the total rises to 125.00 g. At that point the honest description is Method 2 with a partial offset; record it as such.

The three methods side by side

Recording the change

Whichever method you use, the row should show the new strength next to the weight ("Ambroxide 5% in DPG — 10.00 g"), and the change log should say which method and why. A dilution switched with Method 1 is a formulation decision and deserves a new version; one switched with Method 3 is a practical substitution and, by most labs' rules, does not. The version rules are in perfume formula version control, and the general arithmetic of dilutions in a formula is in the perfume dilution and calculations guide.

RUŌOD Lab offers the three methods by name when you change a row's dilution — Preserve Weight, Preserve Percentage (which keeps the pure material) and Exchange Solvent — and recalculates every percentage afterwards. Exchange-solvent draws the difference from rows you have marked as solvent, and the total moves if there is not enough solvent to draw from, exactly as in the example above.

Frequently asked questions

Which method should I use by default?

For a formula you are still developing, keep the pure material (Method 2) unless you deliberately want less of the material. For an approved formula, keep both the pure material and the total (Method 3), so nothing anyone measures changes.

Does changing a dilution change the IFRA position?

Only if the amount of pure material changes. Methods 2 and 3 leave every material's share of the fragrance the same; Method 1 reduces one. Restrictions are always checked on the pure material, as explained in how to calculate IFRA compliance.

Can I switch to a different solvent at the same time?

You can, but treat it as two changes. A different solvent behaves differently in the finished product; see the solvent table in how to dilute aroma chemicals.