What is the scent of our past?

Before the city wakes they are already at work, in kitchens cool from the night, the white skirts and headwraps laid out and waiting for the day. Wide enamel bowls hold aromatic herbs that have been macerated and steeped by Baiana women, in this season, in this combination, for two centuries and counting. Outside, a fanfare for Lavagem do Bonfim, one of Brazil’s largest popular celebrations, is starting in the streets of Salvador, a city in Bahia in the northeastern part of the country. The women crush the leaves with their hands to liberate the smell of resin, mint, something holy. Água de cheiro: the water of smells.

On this day, thousands will walk to the Bonfim church in a visual tide of white clothes. Catholic mass and Afro-Brazilian ritual meet on the same hill, where both an image of Christ, brought from Portugal in 1745, and the Oxalá deity of the African spiritual tradition are honoured. Baianas – descendants of enslaved women who acquired their freedom by vending food and herbs – will pour the scented water over the steps and the heads of pilgrims at the top of the hill, chanting: Do colo da Mãe aos braços do Pai – from the Mother’s lap to the Father’s arms.

But the women fear their rituals will find no echo in the younger generations. Even the landscape has changed; the herbs in their mixture come from an Atlantic Forest fragment that was twice the size when they were young. To prevent this heritage from disappearing forever, researchers of the SCENTinel project have since 2024 documented the scents of crushed herbs and incense before sampling the volatile compounds they release. This pan-European initiative pairs chemistry with practitioners’ own descriptions to construct an archive of what the Lavagem smells like today, against which future change can be measured.

The urgency for such initiatives is real: smell heritage is among the easiest to lose. It does not appear in photographs. It evaporates between two generations. Climate and socioeconomic changes are altering the world’s smellscapes faster than they can be documented, while practitioners around the world often face challenges with intergenerational transmission.

Museums and conservation practice today give priority to the eye. Monuments are looked at, artefacts displayed in glass cases. Intangible heritage is documented through what can be filmed or recorded. Smell is rarely acknowledged, and almost never safeguarded. This reflects a sensory ordering that accompanied modernity: from the 18th century onwards, sight increasingly became associated with reason and knowledge, while smell was pushed toward the body, the domestic, the fleeting and the irrational. In Smell and the Past, the historian William Tullett calls this an ocularcentric account of history, one that still shapes museums, archives and cultural policy today. “When it comes to smell,” he notes, “we often do not know what we have until it disappears, or at least until it alters.”

Yet many forms of heritage are inseparable from smell. Some are objects designed to perfume the body or the air: incense, pomanders, scented gloves, medicinal herbs bundled into ritual waters. Others depend on trained olfactory knowledge: the nose of a perfumer balancing resins and flowers, or a miller judging flour. 

Smell also clings to materials and places themselves. The leathery, smoky, vanilla-like air of a historic library, the dusty notes of a metro station, the damp stone of a church after rain all contribute to what makes a place recognizable and memorable. Yet these sensory dimensions often remain peripheral because they are difficult to classify, collect or archive.

The late 1980s and 1990s saw a “sensory turn” in the humanities and social sciences. Smell, long ranked at the bottom of the Western sensory hierarchy, came under serious cultural and historical study. Heritage science joined in the 2010s, with the publication of a framework to identify and preserve smells with cultural significance. The concept of olfactory heritage emerged. Smelling, in this view, is a way of knowing the world. It is also one of the body’s deepest ways of remembering it.

The scent of a food can summon a whole history; for diasporic communities, familiar smells sustain connections to places left behind. Anosmia during COVID-19 showed how disorienting losing smell can be. At the same time, pollution, industrialization and climate change are altering the smells of regions and seasons: forests shrink, some plant scents disappear. Australian environmental philosopher Glenn Albrecht has described the distress caused by such changes close to home as solastalgia: a form of homesickness without leaving. A river, forest or city may still look familiar while no longer smelling as it once did.

New methods are emerging for documenting and safeguarding smell. For smells that still exist, air samples can be collected from objects, buildings, landscapes, or practices and analyzed using specific techniques to identify the volatile compounds responsible for odour. This is often combined with sensory evaluation in which trained participants describe the smell’s qualities. Together, these methods help create a detailed archive and recreate aspects of the original olfactory experience.

For smells that no longer exist, researchers combine archival sources and historical recipes to recreate them. Such recreations provide a scientifically grounded way to reintroduce lost or endangered sensory dimensions of heritage to contemporary audiences. The European research project Odeuropa exemplifies this through its recovery of the 16th-century pomander – a fragrant metal sphere worn as jewellery and carried as medicine. During the plague, smelling a pomander was believed to offer protection: rosemary, clove, and civet pressed to the nose against the street’s feared odour of sickness and stagnant air. Today, most pomanders survive in museum cases as scentless objects. Odeuropa has rebuilt their fragrance from period recipes. 

Sometimes, the past surprises us. When researchers of the Odotheka project (University of Ljubljana in Slovenia) undertook the first systematic olfactory analysis of Egyptian mummified bodies with the Egyptian Museum in Cairo, they expected the stale odour of enclosed remains. Instead, they encountered something closer to a temple interior: woody resins, incense and sweet balsamic notes surviving across millennia.

The practitioners’ experience is central to Sensing the Intangible, a project at University College London’s Institute for Sustainable Heritage. The initiative has developed a toolkit allowing practitioners to describe the sensory and embodied cues in their own words. Its first case study is English bellringing, sustained by some 30,000 ringers across 7,000 towers. It gathered experiences from the metallic smell of heated bronze and soot to the resonance of sound, rarely captured in formal inventories.

Not every smell should be preserved. The aim is to acknowledge smell’s place in living traditions, places and collections before another practitioner can no longer teach what they know.

Come next January, the Bayana women will pour the água de cheiro over the steps of Bonfim once more, and the scent of basil, myrrh, and incense will rise into the Bahian heat. Yet if the forest herbs disappear, if younger generations no longer learn the ritual, or if sensory knowledge continues to be overlooked, part of the heritage of Bonfim will vanish with them.

The same is true of countless culturally significant smells. Many remain undocumented despite carrying memory, identity and environmental knowledge. As these smellscapes fade, communities lose part of their connection to place. Some forms of heritage survive in stone or paper. Others survive only in the atmosphere, and in people’s memories. Both deserve a record before the air changes – unless we take the trouble to resurrect them.