Headspace: An Interview with Roman Kaiser

1.

Roman Kaiser on the skimmer above the rainforest of French Guiana. Photograph by Kent Lombard.

“Headspace” is a chemist’s and perfumer’s expression. It refers to the volume that an olfactory object, be it a flower or trash, occupies with its diffusing scent. It is, therefore, a spatial term, albeit a space that changes size and shape depending on heat, humidity, and the direction of the breeze. “Headspace” also refers to a cluster of technologies—namely a mixture of adsorption techniques, capillary gas chromatography, and mass spectrometry—that allow the sampling and identification of olfactants. The techniques of headspace were pioneered in the 1970s by scientists working in the flavors and fragrances industry. By the 1990s, the technology was ubiquitous in industry, and thereafter appeared in the practice of artists.

Roman Kaiser was a major figure in the development of headspace techniques, refining the technology in a decades-long study of the fragrances produced by rare plants as orchids studied in situ in rainforest canopies—species that he reached on occasion via a net suspended from an airship. The study of a single flower would typically yield two hundred micrograms of aroma, and so Kaiser might come back from such an expedition with a total of 5 milligrams of material to show for the effort, enough to keep him busy in the lab for six to nine months. Kaiser was also a prolific consultant in perfume design, and his influence is still to be detected, in some form or another, in a not-insignificant proportion of commercial scents on the market today.

FUTURE ANTERIOR:

On the prehistory, and the history, of the headspace method . . .

ROMAN KAISER:

In the beginning, so to speak, there was Nymphaea caerulea, the so-called blue lotus of Egypt, as well as henna and other attractively scented plants. The blue lotus in particular was the holiest flower in ancient Egypt, and its scent was highly desirable. Fragrances had a major role in ancient Egyptian culture. In the pyramids they found documentation of perfume recipes. In order to extract its aroma, it was laid in the fat of cattle. When the fat was saturated, one removed the remains of the plants, and the fat became hard again. One worked the aromatic fat into conical shapes and placed it upon the head. The triangles that you see on the heads of figures in Pharaonic paintings were perfume dispensers. In the eighteenth and nineteenth century these ancient techniques were revisited for highly valued scents such as those of tuberose, narcissus, and jasmine, in particular in the French city of Grasse. One laid the flowers in frameworks charged with purified bovine fat. The fat adsorbs the smell, just as when you leave uncovered butter in the fridge and it adsorbs aromas. This extracting technique is not used any more, it’s simply too onerous.

The headspace technique is, in principle, quite similar, only not destructive. Fat adsorption still requires plucking the flowers. But headspace was from the beginning intended to be essentially a nondestructive process. Historically speaking, classical analytical methods tend to be destructive, but it’s a feature of contemporary techniques is that we can conduct nondestructive analysis. This is for a very good reason, in this case, for one then has access to the rarest of plants.

Instead of bovine fat, one places a highly adsorbent carrier material in this small glass tube that collects traces of olfactants. With headspace, one has to customize the method to the plant. One has to pay close attention that the plant does not suffer, as it might then produce metabolites associated with stress. Normally, in analysis, one tries to completely standardize the methodology, but that is not entirely possible here. For instance, one has to consider at what time of day the flower gives off its scent. Some flowers are only fragrant in the morning, others at midday, others overnight.

There are flowers that are described by botanists as “un-scented” because they have studied them at the wrong time of day. I have discovered about eight...