Flavor Stories: Dr. Roman Kaiser on Saffron's Affinity for Mullet and Shellfish

Shellfish and saffron have a natural affinity for each other. For some, the experience of savoring the flavor of a delicious paella is proof enough. Still, the desire to know why and certain flavors work so well together is enough to keep a curious cook up all night, or in some cases, inspire in a 2438 page corpus on molecular gastronomy.

Dr. Roman Kaiser is a renowned flavor and fragrance chemist who has dedicated his life to analyzing scents emitted by plants in their natural setting. Respectful of plant life and the environment he is known for utilizing dirigibles to conduct fragrance studies in locations including: Lower Amazonia, Papua New Guinea, India, and rainforest biotopes.

These days Dr. Kaiser can be found with both feet on the ground. He retired from Givaudan in 2011 and lectures at European universities. He spends more time doing things that he loves including foraging, canning and cooking; something he did in his youth as he spent a good part of that time in the hills and forests of Switzerland.

It isn't difficult to imagine a curious flavor story Kaiser shares from his childhood. As a young boy he added a few petals of Rosa centifolia from his father's nursery to a batch of homemade raspberry marmalade. The result was a memorable flavor pairing that inspired his pursuit of sensory science as an adult.

Last month I shared a recipe for parsley pesto with Dr. Kaiser via email and confessed that its success was the result of two unplanned events; accidentally buying parsley for a cilantro-based sofrito recipe and deciding to build a dairy-free pesto using the parsley as a flavor base.

I discovered that lemon zest and ground sumac temper garlic and parsley's assertiveness, creating multiple flavor complements. What I knew in the creation process as "instinct" is something I can now share as experience as there are clear reasons why this flavor experiment worked.

Lemon rind is not juicy, but if you add an umami enhancer like ground sumac berry you receive an added benefit; malic acid. Malic acid gives fruit a pleasant tart quality. In adding ground sumac berries to lemon zest one returns a sensory quality to lemon that is associated with a part of fruit that isn't present in the recipe; the juice-filled pulp. The effect is, in essence, a reconstitution of lemon's juicy character without the addition of water. The water forms in the mouth from the savory umami effect.

After sharing the recipe for parsley pesto with Dr. Kaiser he responded with a flavor story of his own. The event took place while he was dining at a restaurant on the Ligurian coast with colleagues (a story he relates on page 150 of his book Meaningful Scents from Around the World). If you're a home cook with a penchant for seafood and saffron you'll appreciate what Dr. Kaiser has to say about science and the role of a cook's instinct in the kitchen:

"...I would also like to describe a culinary insight. I was always wondering how the idea developed to add saffron to shrimps, prawns and red mullet. During a project at the Ligurian coast we once had lunch in a very simple but culinary-wise, wonderful restaurant where we could even see how the dishes were prepared. We had red mullet (rouget, Mullus barbatus) very delicately enhanced in its flavor with saffron, and I suddenly understood why they did this. 

The fresh red mullet itself already has a very faint saffron smell due to minute amounts of safranal and related compounds formed by degradation of carotenoids which gives the typical color to this and some other marine species, including shrimps. In fact, this faint saffron note is also perceivable in fresh shrimps and prawns, in which I have been able to demonstrate the presence of safranal by headspace trapping. 

Another fascinating example illustrating of how people are often able to do the right thing intuitively, in this case to support a very faintly present, but desirable olfactory note with a suitable spice.  

Dr. Kaiser's capacity for discovery defines him as a person and a scientist. These qualities make it a pleasure and privilege to know him. When I returned to read the passage about saffron and shellfish in his book, I found a note from Kate Greene, Vice President of Marketing at Givaudan. The note, written on July 1, 2008, was situated on page 152; one page ahead of the one Dr. Kaiser cited in his email to me. I must have used the note as a bookmark when I was writing about geosmin, a molecule that smells of freshly turned earth. Kate's note read, "On behalf of Roman, please enjoy his amazing book- it has given all of us much inspiration."

Meaningful Scents from Around the World has the approachable tone of an observational diary with a provocative scholarly flavor. It continues to attract readers because the human element in Dr. Kaiser's work, which is as much about curiosity as it is about science, is timeless. September 16th marks the eighth year since the book was published. Meaningful Scents from Around the World continues to inspire me. I have a feeling it always will...

Notes:
Details regarding Dr. Roman Kaiser's childhood discovery of rose-raspberry flavor pairing can be found in an interview conducted by Dyptique.

Dr. Roman Kaiser pioneered an aroma capturing technique in the 70's referred to as "headspace" trapping. This technique allows scent samples to be collected in the field without harming the plant.

Image of a dirigible from a ScentTrek® in Madagascar's Masaola Peninsula via Givaudan.

Image of a pint of red raspberries by Dan Klimke via Creative Commons.

Image of saffron threads by David Hawkins-Weeks via Creative Commons.

A big thanks to my husband, A.J. Kydd, who encouraged me to invent something new when I bought the wrong herb at the grocery store. It's nice to be reminded that mistakes and inconveniences are often opportunities in disguise.

"Inside the Olfactory Mind of Dr. Roman Kaiser" continues to be the most popular post on Glass Petal Smoke to date. It is part of a series of interviews regarding the sense of smell and memory.

Inside the Olfactory Mind of Dr. Roman Kaiser

Roman Kaiser is a native of Switzerland. He is a chemist, naturalist and perfumer. Dr. Kaiser has spent a good part of his professional life analyzing plants and their scents. In his new book, Scent of the Vanishing Flora, he shares details on 267 endangered flowers that are disappearing due to habitat loss. He has graciously agreed to take the Glass Petal Smoke "Sensory Questionnaire" and share his flavor and fragrance memories. 

 1.  What does your sense of smell mean to you?

The sense of smell adds a dimension of perception to my life which is, in its intensity, equal to the sense of vision and hearing. Although I always had a high affinity to this perception it developed immensely during my forty years of studying natural scents at Givaudan. During this time I evaluated around 9000 scented plant species from which I had the opportunity to study an additional 2700 plants on the same scientific level. This broad olfactory experience with scents helps me to understand many things I encounter in this world, which also brings me also closer to people around me. Not less important is the fact that the sense of smell enormously enhances my acoustic and visual perception and, to a certain degree, vice versa. Thus, if I hear Vivaldi’s “The Four Seasons” the corresponding typical scents, as you would experience them in my home country of Switzerland, become active in my olfactory mind.

 2.  What are some of your strongest scent memories?

At the age of 12 I had to spend a rather long time in a hospital. One of the nurses always smelled of a famous fougère soap which is still available today. She was always kind to me and in this situation I associated the scent with all of the things that make life worth living.

Earlier, when I was a small boy, I discovered a place in a nearby forest with huge amounts of wild strawberries, a secret place which I never failed to visit. This is certainly the reason why I understand the strawberry’s olfactory concept very well.

Another discovery I made around this time was in a sun-flooded pine forest in the foothills of our region. There was a group of plants with flower stems rising to a height of 30 centimeters, each with as many as 15 to 20 dark purple-red flowers which had a wonderful vanilla-like and aromatic spicy fragrance. This fragrance helped to imprint the plant’s visual appearance so that 25 years later, when I started to study orchids in more detail, it came back to my mind and I could identify it before seeing it again as Epipactis atrorubens. I went back to this habitat and was happy to find this population still existing and see that it was, indeed, Epipactis atrorubens, the so-called Dark Red Helleborine.

 3.  What are some of your favorite smells (things in nature, cooking and/or your environment)?

Fully ripe lemon fruits which one may find along the Amalfi coast in Italy. I was so attracted to this scent that I studied it in more detail in the mid 1980’s. As a result I discovered that methyl epi-jasmonate is strongly accumulated on the peel surface and gives this unique far-reaching hesperidic floral note.

It is no wonder that I also feel drawn to the scent of the To-yo-ran Orchid Cymbidium goeringii. This flower scent is also very rich in methyl epi-jasmonate and related jasminoid compounds.

Another of my favorite scents is the olfactory ambiance along a Mediterranean pine forest during a sunny afternoon. As I finally discovered the characteristic part of this scent, a wonderful musky-woody note was arising, not from the needles, the cones or the wood, but from the sunshine-exposed resin. Under such conditions long chain hydroxy acids present in the resin may internally cyclize to macrocyclic lactones* that are responsible for this olfactory delight.

My third favorite smell is one that rises from burning agarwood; the wood of the gods. Many years ago I spent an evening in New York as a guest in a house where high quality agarwood had been transformed into this heavenly incense smoke. It is beyond a simply pleasant smell – it invades your lungs, your entire body and mind, taking total possession of you. You smell it for days, sometimes wondering what it might be and where it might be coming from, then it comes back to your mind as a constant reminder.

 4.  Do you have any favorite smells that are considered strange?

 
No, not really, but people around me sometimes have the idea that I possess a special love for strange scents. For example, they may see me sniffing at wet rocks or snow in the mountains, but there is a good reason for this; on wet rocks you may find certain algae species emitting interesting scents. One species is even capable of degrading carotenoids to beta-ionone and related compounds. Finding a violet-type scent in algae species is quite an experience. At such high altitudes there are also scent producing algae which may be found on snow or ice. Such is the case of Chlamydomonas nivalis, which emits the scent of watermelon.

 5.  Describe one or more of your favorite cooking smells.

The smell developing if you briefly roast cut aubergine in a good olive oil is a real olfactory revelation; it is the aroma that tells you how to use this delicacy in gourmet recipes. An equally fascinating yet quite different smell develops if you briefly roast scallops in high quality olive oil.

 6.  What smells do you most dislike?

Carrion, skunk in action and rotting aubergine.

 
 7.  What smell did you first dislike, but learned to love?

It took me a rather long time to learn how to appreciate the highly characteristic scent of white truffle. One of the reasons might have been my exposure to many olive oils that are over-flavored with white truffle essence. I often had the feeling that they were too strongly fortified with the impact chemical of white truffle, 2,4-dithiapentane, which is, however, a great product at the right dosage.

 8.  What mundane smells inspire you?

Freshly brewed coffee, freshly baked bread, rain after a hot day, and the smell of people as they pass who are wearing a good fragrance.
 

 9.  What scent never fails to take you back in time and why? 

Lime Tree blossom** and frankincense are two characteristic scents of my youth which work exactly in this way. The tender and romantic scent of lime tree blossom is emblematic in Middle Europe for feeling at home and no one has better expressed this than Franz Schubert with the famous song “Am Brunnen vor dem Tore.” This is how I experienced this magnificent tree and its flower scent in my home village near Mount Säntis in eastern Switzerland, magical to all those living around it. It is also admired in cities. What would Zürich’s famous “Bahnhofstrasse” be without the lime tree! Everybody experiencing it during its flowering in June is enthusiastic about it. The most impressive feature of my rather small home village is a baroque church dominating everything. If I recognize frankincense in a fragrance I have to think immediately of these Sunday services I always attended as a boy. I re-experience the sacred music, the glamorous liturgy and this unique scent pervading everything.

 10.  What scents do you associate with memories of loved ones?

 The classic Eau De Cologne 4711 as my mother used it.

 11.  What fragrance(s) remind you of growing up? 

There’s the two I previously mentioned; lime tree blossom and frankincense. Other fragrances that strongly remind me of growing up are also closely connected to my home village which is surrounded by hills and forests. The scents of flowering meadows as well as those of the hay produced from them are imprinted in my olfactory memory. In the forests I could never resist sniffing the pine and fir resin and I even know how they taste. This is because as a boy I read a book which said that the Indians of North America would chew, instead of chewing gum, such tree resins. I was also exposed to beautiful flower scents at a very young age because my father had a nursery and cultivated, among others, roses, sweet peas and all types of spring flowers for the flower trade.

 12. What fragrance(s) remind you of the places you visited on vacation?

The scent of sun exposed pine resin, which I previously described, reminds me of my visits to the Ligurian coast and the Côte d’Azur. But much earlier I became preconditioned to the unique, baroque, aromatic-floral, vanilla and cocoa-related scent of the Black Vanilla Orchid, a rare and precious jewel of our mountain meadows. This fragrance type carries me immediately to the Swiss mountains where we spend some of our vacation days every summer. In a similar way the scent of carnation (type Dianthus caryophyllus) carries me to the very small island of Hoëdic, situated in the Atlantic around 30 kilometers south of Quiberon in France. If you visit this island at the end of June or beginning of July you can already smell the very spicy-floral scent of carnation 300 meters before arriving at the harbor. Exploring this tiny island you will find the source of this unique environmental scent in a countless number of flowering Dianthus gallicus which for me, places Hoëdic among the 100 unforgettable olfactory sceneries of this world.

13.  Describe a piece of sensory literature that is very magical for you.

There are many books in this domain worth reading, but to start I would suggest Jitterbug Perfume by Tom Robbins. But do not believe too much in the flower and pollen scent of red beets; they are not as magical as described.

Notes:

*Macrocyclic lactones in plants are usually responsible for their musk aromas.

**Lime Tree is the European reference to the Linden Tree. They are one and the same.

Photograph of dark red helliborine taken by DJS Photography. Many beautiful prints are available for purchase on the website.

Photograph of agarwood (also known as aloeswood and oud) is from Shoyeido, a fine purveyor of agarwood chips for incense burning.

Photograph of Chlamydomonas nivalis growing on an Austrian mountain taken by Petr Jan Juračka.

Photograph of Black Vanilla Orchid from Plas y Brenin. 

Photograph of the alpine strawberry taken by Terry Ferdinand of the BBC.

Photograph of skunk in the act of spraying from PBS.org.

Photograph of frankincense burning on charcoal by Michelle Krell Kydd.  

Photograph of Dr. Roman Kaiser has been provided by Givaudan.

Royal Paulownia: The Perfume of Spring Along the Hudson

When May roses begin to perfume the air violet blooms burst forth on Royal Paulownias that grow along the edge of the Hudson River. There is no time to mourn fading purple lilacs when the trumpet-like clusters of Paulownia tomentosa release their fragrance. Their scent reveals a riverside terroir that smells ozonic, vanillic, powdery and almond-like. The fragrance is most prominent when dusk arrives. That is also the time when people who never look up at the towering trees recognize the source of their olfactive pleasure. Few people, however, know the folklore behind these trees and how they became naturalized in the United States.

Paulownia tomentosa is also known as the Empress or Princess Tree. The genus Paulownia is named in honor of Anna Pavlovna (Paulowna by Dutch transliteration), the daughter of Czar Paul I. In China it is customary to plant an Empress Tree when a baby girl is born. The maturity of the tree and the girl coincide. When she is eligible for marriage the tree is cut down to make a wedding chest. The presence of an Empress Tree near a home is considered good luck as it is said to be favored by the mythical Phoenix who is drawn to its branches. In Japan, if a Paulownia drops its leaves early in the season, it is considered bad luck. During World War II the United States dropped paper Paulownia (Kiri) leaves on Japan that included ominous propaganda meant to play on the "bad luck" folklore attached to the leaves of the tree.











In the mid 1800s Chinese porcelain was transported by train in the United States. The materials used to pack these delicate objects were Paulownia seed pods. Each pod contains up to 2000 small-winged seeds and resembles a giant pistachio nut. Some seeds escaped during transit while others were released at their destination and carried by the wind. It is likely that Chinese porcelain making its way down the New York Central Railroad is responsible for the Paulownia trees along the Metro North Hudson Line.

Though Paulownia tomentosa is considered an invasive species that escaped cultivation it possesses a delicate nature and is particularly sensitive to weed killers and pesticides. It can also tolerate high salinity and drought. This makes portions of the Hudson River shoreline ideal for a tree that can reach up to 15 feet in one season and 30 feet in three years. When Paulownias are in bloom their scent is carried by the wind along the Hudson River, perfuming the shoreline and mesmerizing anyone fortunate enough to participate in a landscape that includes them.

Givaudan's Roman Kaiser analyzed the scent of Paulownia tomentosa flowers in 1995. When Glass Petal Smoke asked him if there was a little heliotropin in the mix Kaiser responded with scientific precision, “This heliotropin related note is mainly generated by the interaction of the main constituent hydroquinone dimethyl ether with beta-ionone including derivatives and methyl cinnamate. Methyl benzoate, methyl salicylate and methyl 2-methoxybenzoate round this accord off.” Heliotropin is a molecule found in vanilla and smells floral, vanillic, and slightly almond-like (there is a lot of heliotropin in Tahitian vanilla beans). Kaiser’s complete analysis of Paulownia tomentosa is as follows:

Methyl 2-Methybutyrate 0.10
Methyl Caproate 0.10
(E)-Ocimene 0.60
6-Methyl-5-Hepten-2-One 0.30
Nonanal 0.05
Benzaldehyde 0.05
Linalool 0.05
Cyclic-Beta-Ionone 0.10
Methyl Benzoate 5.50
(E)-Beta-Farnesene 0.20
Hydroquinone Dimethyl Ether 79.00
Methyl Salicylate 1.90
Dihyro-Beta-Ionone 1.20
Benzyl Alcohol 0.80
Beta-Ionone 6.00
Methyl- (E)-Cinnamate 0.90
Methyl2-Methoxybenzoate 2.70
Benzyl Benzoate 0.10

Total: 99.65

Notes:

Hudson River painting of Royal Paulownia by Jamie Williams Grossman. All rights revert back to the artist.

Photos of Paulownia seed pods from the Oregon State Department of Horticulture .

Some of the fragrance ingredients in Roman Kaiser's analysis of Paulownia tomentosa can be found on Givaudan's website by clicking here. You can cut and paste the name of the molecule to research it. The Good Scents Company has an extensive database of raw materials. Perhaps we will see this kind of organoleptic information democratized in Wolfram/Alpha as the new search engine develops its très cool chemistry section.

Analysis of fragrance molecules is conducted by gas chromatography-mass spectrometry (also known as "GC mass spec" in the fragrance business). The machine analyzes scent, but requires the technical and olfactive skills of a trained professional for optimal results.