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A sample to practise on

An analysis built for you to try reading while working through Part Two. Not a product; no lot corresponds to it.

• Reading an analysis Volatility band, component table, and six harvests side by side

Part One — Learning to smell

You leave this part with three smell reference points you can check for yourself in your own kitchen tonight. No equipment, nothing much to buy.

1. You don’t lack a sense of smell — you lack words An ordinary person can tell thousands of smells apart but name only a few dozen. The gap is not in the nose.
2. Smell reference points already in your kitchen You don’t need to buy anything to start. Most of this dictionary is in your kitchen cupboard and at the market down the street.
3. How to smell something three times in three minutes One long sniff tells you less than three short ones. The reason lies in how olfactory receptors work.
4. Lime peel and lime leaf are not one smell One tree, two parts, two different leading molecules. This is the first lesson, and it applies to everything that follows.
5. Sticky rice and pandan: two species, one molecule Two unrelated organisms give the same smell. That tells you a smell does not belong to a plant species.
6. A smell is a process, not a state A pan of sugar shows you the whole life of a smell in thirty seconds.
7. Concentration decides the nature of a smell, not just its strength The same molecule can be white flowers at one dose and faeces at another. This is the most counter-intuitive fact in all of smell.
8. Why you can’t smell your own home Your nose is hiding most of what it picks up, and it has good reason to.
9. First rain is the smell of bacteria Rain has no smell. What you smell was already lying in the soil, waiting to be thrown up into the air.

Part Two — Learning to resolve

Look at a table of GC/MS results and know which lines matter. This is where most people stop.

1. A smell is not one thing — it is a list The hardest shift in the whole course: stop treating a smell as a block and start treating it as a sum with terms.
2. Boiling point decides the order in which you smell things Why a number measured in a laboratory says something about your experience on a smelling strip.
3. Read a chromatogram like a fragrance’s notes The horizontal axis of a GC/MS analysis is the time axis of your smelling experience. This lesson shows why, and the four places where the match no longer holds.
4. Area percentage is not mass percentage The numbers on an analysis are not the mass shares most people take them to be.
5. Why the components never add up to exactly one hundred An analysis that adds up to 90 per cent is normal. One that adds up to 99.8 is worth questioning — except for a few oils that are simple by nature.
6. Odour threshold: why one part in ten thousand can drown out forty per cent This is the most counter-intuitive thing about reading an analysis, and the place where most people draw the wrong conclusion.
7. Trace components decide character, main components decide type The two largest components tell you what kind of essential oil this is. The thirty smallest tell you which bottle it is.
8. Isomers: same formula, different smell Two compounds with the same number of atoms of the same elements can still smell completely different. Position matters as much as composition.
9. Retention time means something only if you know the column The minutes on an analysis are meaningless without one line of information that many analyses leave out.
10. Ten components you will meet in almost every report Learn these ten compounds well and you can read most essential-oil analyses without looking anything up.

Part Three — Learning origins

Understand why two bottles with the same name are not the same thing. Land, altitude, season, plant part, extraction method.

1. Nine ways to get smell out of a plant Each method takes a different part of the plant and leaves another part behind. No method takes everything.
2. Why jasmine cannot be distilled Heat destroys exactly the molecules that make jasmine. What you get is not the smell of the flower but its corpse.
3. Chemotype: one species, two natures Two plants with the same scientific name, grown in two regions, can give two essential oils that cannot stand in for each other.
4. Region, altitude, season — three things that change an analysis The same variety, the same extraction method, and the analyses still differ. This is why.
5. What the plant part decides The peel, leaves, flowers, roots and seeds of one plant can give five essential oils with nothing to do with each other.
6. How many kilos of flowers for a kilo of essential oil Extraction yield explains almost all the price differences in the trade, and it also explains why fakes exist.
7. Why essential oils have a shelf life Not because of bacteria. Because of oxygen, and each essential oil spoils at its own pace.
8. Hydrosol: what remains after distillation A still produces two products. The second was poured away for centuries before anyone realised what it was.
9. Grasse: how a tanning town became the capital of perfume The modern perfume industry was born from a problem of bad smells, not from an aesthetic aspiration.
10. The road of attar: how distillation travelled from Persia to Europe Arab and Persian alchemists perfected the still, and it reached Europe much later than people assume.
11. A species name does not guarantee a smell Four ways in which a correct name can still mislead you about what is in the bottle.

Part Four — Learning to doubt

Know which questions to ask a seller, including us. This part works against the people who wrote it, and that is why it has to exist.

1. One hundred per cent pure is a claim, not a certificate No authority issues anything called a purity certificate. The phrase on the label is worth exactly the reputation of whoever printed it.
2. Real or fake essential oil: four ways of diluting, and the traces they leave Telling real essential oil from fake starts with the simplest layer of fraud — dilution — which is also the easiest to detect, if you know where to look.
3. Filling with a cheaper oil from the same group The second layer is subtler: instead of diluting with oil, the blender adds another essential oil with a similar smell that costs many times less.
4. When an essential oil is filled with its own component The third layer: adding a pure compound to make the analysis look better than reality. This is where GC/MS usually starts to fail.
5. Chiral chromatography: same structure, different origin Many molecules come in two mirror-image forms. Plants make them in one ratio, factories in another — and that gap is what allows detection.
6. Carbon isotope ratio: the final evidence Plants and petroleum hold carbon in two different isotope ratios. It is a trace that cannot be erased, and it lies beyond the reach of any blending.
7. Checking essential oils with GC/MS: how to read the report a seller gives you A seller hands you a GC/MS analysis — how to read it to know what it proves, what it does not, and where it is most often faked.
8. Six things sellers often say that you should question Not because they are lying. Because those phrases sound like information but carry none.
9. The limits of every essential-oil test — GC/MS included The four layers of fraud in the essential-oil trade, and which one an ordinary GC/MS analysis cannot detect.