Every few months I take out a box of essential oils and carefully lay them out on my kitchen table, organising them in order from sweet-smelling to musty. On the left will be scents like juniper berry, lime, frankincense and bergamot; in the middle, woodish fragrances such as sandalwood and cedarwood; on the right, the darker stuff of patchouli and pine needle – and occasionally, when I’m feeling brave in my endeavour to make the perfect beard oil, lavender.