The Scottish Highlands in winter are a wild and elemental place. Snow gleams white atop blue-black mountains; curves of glassy water rush over rocky beds; juniper bushes grow low, bent by the wind and birch trees stand tall, silhouetted against the tawny greens of tumbling hills. The air, pure and clear, is crisp and bitterly cold.

For Winter 21, it is the unique quality of this highland air which we have sought to capture; lacking in moisture it hangs like silk, allowing each note to sing with a sharper clarity.

To begin, we set about building a cool, fresh palette. For this we turned to lemon, eucalyptus, peppermint and lavender. Though removed from the Scottish landscape, all bring with them an innate cooling effect. Onto this backdrop we layered the scent of juniper - herbaceous and spicy, like crushed black pepper - and the woody, resinous notes of fir balsam and cedar, with their distinctive evergreen edge.

Threading through this land are sky-blue streams. Composed from falling rain, and filtered by rock, they run seawards with gathering strength. As they go, they offer up the smell of wet pebbles, tangled mosses and dense, damp earth. To emulate this, we married oakmoss with tarragon and seaweed. This accord created an earthy, succulent and faintly herbal aroma.

Painting this highland scene was an enjoyable task. Yet the more we explored it, the more there seemed an absence. Both the scene and scent were lacking. Perhaps, to counter the cold mineral air, we needed some warmth, some comfort amidst the hostile terrain. And so we began to imagine a cabin in the distance, a rising plume of smoke.

We experimented with birch tar - full bodied and peaty, like an old whisky - and combined it with the spicy notes of cardamom, clove buds and a hint of patchouli. Together, they would suggest the familiar warmth of a cabin interior. The result was just as we had hoped, balancing the notes of the fragrance and giving it new depth and character.