Odor can be characterised using a list of standard descriptors which can vary between countries. When a panel of assessors are exposed to an odor, they are asked to describe it in terms of a given list of adjectives, and assign it an intensity on a predetermined scale. Often a 0 (faint) to 5 (strong) scale is used.
Eight odor descriptor macro-categories are usually adopted, each of them has specific descriptors, as illustrated a following figure. Odor descriptors and their intensity can be represented in a odor descriptor-rose. In analogy with the wind-rose, which represents the wind intensity in each direction, the odor descriptor rose represents the odor intensity for each macro-category. An example of such rose, produced with the WindRose PRO software, is represented in a following figure.
The macro-categories and their specific descriptors are:
- Flora: Almond, Cinnamon, Coconut, Eucalyptus, Fragrant, Herbal, Lavender, Liquirice, Marigolds, Perfumy, Roses, Spicy, Vanilla
- Fruity: Apple, Cherry, Citrus, Cloves, Grapes, Lemon, Maple, Melon, Minty, Orange, Strawberry, Sweet
- Vegetable: Celery, Corn, Cucumber, Dill, Garlic, Green pepper, Nutty, Potato, Tomato, Onion
- Earthy: Ashes, Burnt wood, Chalk, Coffee, Grain silage, Grassy, Mould, Mouse-like, Mushroom, Musky, Musty, Peat, Pine, Smoky, Stale, Swampy, Woody, Yeast
- Offensive: Blood, Burnt, Burnt rubber, Decay, Faecal, Refuse, Landfill leachate, Manure, Mercaptan, Putrid, Rancid, Raw meat, Rotten eggs, Septic, Sewer, Sour, Spoiled milk, Urine, Vomit
- Fishy: Amine, Dead fish, Perming solution
- Chemical: Burnt plastic, Car exhaust, Cleaning fluid, Coal, Creosote, Diesel, Petrol, Grease, Foundry, Kerosene, Molasses, Mothballs, Oil, Paint, Petroleum, Plastic, Resins, Rubber, Solvent, Styrene, Sulphur, Tar/Asphalt, Turps, Varnish, Vinyl
- Medicinal: Alcohol, Ammonia, Anaesthetic, Camphor, Chlorine, Disinfectant, Menthol, Soap, Vinegar
Odor is also characterised by means of taste and sensation.