The Notes
Hay
Hay in perfume smells of a meadow cut in June and dried in the sun: sweet, warm and herbal, with a hint of tobacco.
Hay in perfume smells of a meadow cut in June and left to dry in the sun: sweet, warm and a little herbal, with hints of tobacco and honey. Much of that sweetness is one molecule, coumarin, and perfumers capture it either as hay absolute, extracted from dried grasses, or as coumarin itself.
Why drying grass smells sweet
Fresh grass smells green and sappy rather than sweet. In many meadow plants, coumarin is held in the living leaf bound to a sugar, in a form that does not evaporate. When the stems are cut and begin to wilt, an enzyme strips away the sugar and free coumarin is released into the air. Sweet vernal grass, Anthoxanthum odoratum, a native of British meadows and the first grass to flower in spring, is one of the plants that does this, and smells strongly of new-mown hay when crushed or dried. Sweet clover and woodruff work the same trick.
Hay absolute
Hay absolute is made by solvent extraction of cut, dried grasses, mostly in France. The species vary from producer to producer and may include sweet vernal grass or sweetgrass (Hierochloe). The solvent first yields a waxy concrete, which is purified with alcohol to give the absolute, a thick liquid somewhere between dark green and brown. Grasse produces one under its own geographical indication.
What it smells like
Hay absolute is sweet and diffusive, coumarin at its centre but rounder than coumarin alone, with herbal and faintly jammy, dried-fig undertones and a soft edge of tobacco and moss. It is the smell of a barn loft in August, with the bales still warm.
How perfumers use it
Hay sits in the heart and base. It belongs naturally in fougères, the fern family built on lavender, moss and coumarin, and in tobacco and leather accords, and it blends with tonka bean, lavender, vetiver and oakmoss. The link to tobacco is close: cured tobacco leaf carries a hay-like sweetness of its own. Because coumarin is restricted under IFRA standards, hay absolute is dosed with care.
In our fragrances
Saddle Room has hay absolute in its heart, with supple suede and the faintest smoke of birch tar; tonka bean, sandalwood and a leather accord follow in the base. It is there because a tack room before the meet smells as much of hay as of saddles. There is more in Notes from the Tack Room.