Coumarin is a naturally occurring aromatic compound with a warm, sweet, vanilla-and-new-mown-hay scent. It comes as a white crystalline powder (chemical formula C9H6O2, CAS 91-64-5) and is used mainly as a fragrance ingredient and fixative in perfumery, candles, soaps and other scented products. Azlok stocks food-grade quality coumarin in packs from 50 grams up to 25 kilograms for hobbyists and small manufacturers alike.
What is coumarin?
Coumarin occurs in several plants, most famously tonka beans, but also cassia cinnamon, sweet clover and woodruff. That characteristic hay-like sweetness you notice in freshly cut grass on a warm day is largely thanks to coumarin. In the fragrance trade it is prized because it smells rich and comforting while also helping to round off and hold a blend together.
Chemically it is a benzopyrone. In its pure form it appears as fine white crystals or powder that dissolve readily in alcohol and oils but poorly in water.
Common uses of coumarin
- Perfumery: A classic building block of the "fougère" family, coumarin adds a soft, tobacco-and-vanilla warmth that pairs beautifully with lavender, oakmoss and bergamot.
- Fixative: Because it is relatively low in volatility, coumarin helps anchor lighter top notes so a fragrance lasts longer.
- Candle making: Added to candle blends, it lends a cosy, sweet-hay background that suits gourmand and amber-type scents.
- Soap and cosmetics: Used at small percentages in cold-process soap, lotions and other personal-care formulations for a comforting aroma.
- Aromatherapy blends and diffuser oils: Contributes a mellow, sweet base note.
How to use coumarin
Coumarin is potent, so a little goes a long way. Because it is a solid, most makers dissolve it before use.
- Make a working solution: Dissolve the crystals in perfumer's alcohol or a suitable carrier at a known concentration (for example, 10%) so you can measure it accurately by drops or weight.
- Blend in small amounts: Start with a fraction of a percent of your total fragrance formula and adjust. Overdosing makes a blend heavy and cloying.
- Let it mature: After blending a perfume, allow it to rest for a few days to a couple of weeks so the notes marry.
- For candles and soap: Follow your usual fragrance-load guidelines and factor coumarin in as part of the overall scent, not on top of it.
Safety notes
Treat coumarin as a concentrated raw material, not a finished product.
- Do not ingest. Although coumarin occurs in foods, isolated coumarin is not intended for direct consumption and can be harmful in quantity.
- Patch-test and dilute. It can be a skin sensitiser for some people. Observe recognised usage limits (such as IFRA guidance) when making skin products, and always keep it well diluted.
- Handle the powder carefully. Work in a ventilated space, avoid breathing in the dust, and wear gloves when weighing.
- Keep away from children and pets, and store separately from food.
- Consult the COA and MSDS for the specific batch you buy before formulating.
Buying and storage tips
Choose a pack size that matches how often you make things. For occasional DIY, the 50 GM or 100 Gm packs are sensible; small businesses may prefer the 500 GM to 25 KG options. Coumarin from Azlok has a stated shelf life of about 12 months when stored well.
- Keep it in a tightly closed container, away from heat, moisture and direct sunlight.
- Store in a cool, dark cupboard; the crystals can clump if exposed to humidity.
- Label the container clearly with the name and date opened.
- Use clean, dry spoons to avoid introducing moisture.
FAQ
What does coumarin smell like?
It has a sweet, warm aroma reminiscent of vanilla, freshly cut hay and tonka bean, with a slightly powdery, tobacco-like edge.
Is coumarin natural or synthetic?
Coumarin occurs naturally in plants like tonka beans, cinnamon and sweet clover, but the material sold for fragrance use is usually produced synthetically to a consistent purity.
Can I use coumarin in soap and candles?
Yes. It is widely used in both, added as part of the fragrance blend at small percentages. Follow standard fragrance-load and safety guidelines for your product type.
Is coumarin safe to eat?
No. Isolated coumarin is meant for fragrance and industrial use, not for direct consumption. Do not add it to food.
How should I store coumarin to keep it fresh?
Keep it in an airtight container in a cool, dark, dry place away from sunlight and moisture, and use it within its 12-month shelf life for best results.