Solvents & Diluents in Perfumery: Perfumer's Alcohol, DPG, TEC & DEP

One of the first practical questions every beginner asks is the classic perfumers alcohol vs DPG debate: which carrier should I dilute my materials in, and why bother diluting at all? Understanding solvents and diluents is genuinely the difference between hobbyists who struggle and perfumers who get consistent, professional results. This guide walks through the why and the how, then breaks down the four diluents you will use most.

Why Perfumers Dilute Everything

A finished perfume is mostly solvent. A typical eau de parfum might be only 15-25% fragrance concentrate dissolved in alcohol; the rest is the carrier. But dilution happens long before the final bottle. Perfumers dilute their individual raw materials too, usually to 10% (and sometimes 1% for ultra-powerful aroma chemicals). There are four big reasons:

• Accuracy: many aroma chemicals are so strong that a single drop neat would overwhelm a formula. A 10% dilution lets you dose by the drop with real control.
• Safety: diluting reduces the risk of skin contact with concentrated materials and makes handling far safer.
• Smelling: a material's true character only appears at usable strength. Diluted strips give an honest picture of how it will behave in a blend.
• Handling solids and viscous liquids: crystalline or thick materials become pourable, measurable liquids once dissolved.

Perfumer's Alcohol

Perfumer's alcohol is high-purity ethanol, usually denatured and often blended with a small amount of a fixative or moisturiser. It is the standard carrier for the finished spray fragrance.

• Pros: evaporates cleanly leaving the fragrance on the skin; gives that crisp "spritz" and lift; odourless when good quality; ideal for eau de parfum and eau de toilette.
• Cons: volatile and flammable; in India it can be expensive and subject to excise rules; evaporates so fast it is poor for making stable stock dilutions of materials you want to keep for months.

DPG (Dipropylene Glycol)

DPG is the workhorse diluent of the industry — a nearly odourless, low-volatility glycol used to dilute aroma chemicals into stable stock solutions.

• Pros: very low odour; cheap; does not evaporate, so your 10% dilutions stay stable for a long time; mild and skin-friendly; excellent general-purpose carrier.
• Cons: mildly slows down the throw of a finished perfume because it is not volatile; not suitable as the main carrier for a true alcohol spray.

TEC (Triethyl Citrate)

TEC is a citrate ester diluent prized for being effectively odourless and gentle. It doubles as a mild fixative.

• Pros: extremely low odour; food-contact safe grades exist; acts as a light fixative, slightly extending longevity; excellent for oil-based perfumes, solid perfumes and roll-ons.
• Cons: more expensive than DPG; slightly more viscous. Explore food-grade TEC (triethyl citrate) when you want a clean, skin-pleasant carrier.

DEP (Diethyl Phthalate)

DEP was for decades the default diluent and fixative in commercial perfumery, valued for being cheap and odourless.

• Pros: very low odour; inexpensive; good fixative properties; long shelf life.
• Cons: as a phthalate it has attracted consumer and regulatory scrutiny; many modern indie perfumers prefer DPG or TEC for a cleaner-label product, especially for skin application.

How to Dose and Dilute Aroma Chemicals

A simple, reliable workflow:

• Make stock dilutions: dissolve most materials at 10% in DPG or TEC by weight (1 g material + 9 g diluent). Use 1% for the most powerful chemicals.
• Work by weight: a digital scale accurate to 0.01 g beats counting drops for repeatable formulas.
• Choose the carrier for the job: DPG or TEC for stock dilutions and oil perfumes; perfumer's alcohol for the final spray.
• Protect your work: citrus and many fresh materials oxidise over time. A pinch of antioxidant such as BHT at around 0.1% helps keep dilutions and finished perfumes from going off.
• Label everything: note the material, percentage, diluent and date. Future-you will be grateful.

A quick way to decide between the four: if you are bottling a spray perfume, the bulk carrier is perfumer's alcohol. If you are building stock dilutions of raw materials to keep on your bench, reach for DPG as the cheap default or TEC when you want a slightly skin-friendlier, lightly fixative carrier. For oil-based and roll-on perfumes that sit directly on skin, TEC is hard to beat. DEP still works and remains inexpensive, but many indie makers now skip it for cleaner-label reasons. There is no single "best" diluent — only the right one for the format you are making.

Safety: always patch test finished blends on the inner forearm for 24 hours, keep alcohol away from flame, and respect IFRA limits for the individual fragrance materials regardless of which solvent you dilute them in. The solvent does not change a restricted material's safe usage level.

Master your diluents and everything else in perfumery becomes easier, more accurate and more repeatable. Stock up on quality solvents, fixatives and aroma chemicals across our full range in all products at Unravel Perfumery.

Shop the materials in this article

• Tri Ethyl Citrate (TEC) Indian Make
• Butyl Hydroxy Toluene (BHT) Russian Make

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